TY - JOUR
AB - Production of hydrogen at large scale requires development of non-noble, inexpensive, and high-performing catalysts for constructing water-splitting devices. Herein, we report the synthesis of Zn-doped NiO heterostructure (ZnNiO) catalysts at room temperature via a coprecipitation method followed by drying (at 80 °C, 6 h) and calcination at an elevated temperature of 400 °C for 5 h under three distinct conditions, namely, air, N2, and vacuum. The vacuum-synthesized catalyst demonstrates a low overpotential of 88 mV at −10 mA cm–2 and a small Tafel slope of 73 mV dec–1 suggesting relatively higher charge transfer kinetics for hydrogen evolution reactions (HER) compared with the specimens synthesized under N2 or O2 atmosphere. It also demonstrates an oxygen evolution (OER) overpotential of 260 mV at 10 mA cm–2 with a low Tafel slope of 63 mV dec–1. In a full-cell water-splitting device, the vacuum-synthesized ZnNiO heterostructure demonstrates a cell voltage of 1.94 V at 50 mA cm–2 and shows remarkable stability over 24 h at a high current density of 100 mA cm–2. It is also demonstrated in this study that Zn-doping, surface, and interface engineering in transition-metal oxides play a crucial role in efficient electrocatalytic water splitting. Also, the results obtained from density functional theory (DFT + U = 0–8 eV), where U is the on-site Coulomb repulsion parameter also known as Hubbard U, based electronic structure calculations confirm that Zn doping constructively modifies the electronic structure, in both the valence band and the conduction band, and found to be suitable in tailoring the carrier’s effective masses of electrons and holes. The decrease in electron’s effective masses together with large differences between the effective masses of electrons and holes is noticed, which is found to be mainly responsible for achieving the best water-splitting performance from a 9% Zn-doped NiO sample prepared under vacuum.
AU - Kiran, Gundegowda Kalligowdanadoddi
AU - Singh, Saurabh
AU - Mahato, Neelima
AU - Sreekanth, Thupakula Venkata Madhukar
AU - Dillip, Gowra Raghupathy
AU - Yoo, Kisoo
AU - Kim, Jonghoon
ID - 14828
IS - 1
JF - ACS Applied Energy Materials
KW - Electrical and Electronic Engineering
KW - Materials Chemistry
KW - Electrochemistry
KW - Energy Engineering and Power Technology
KW - Chemical Engineering (miscellaneous)
SN - 2574-0962
TI - Interface engineering modulation combined with electronic structure modification of Zn-doped NiO heterostructure for efficient water-splitting activity
VL - 7
ER -
TY - JOUR
AB - As a key liquid organic hydrogen carrier, investigating the decomposition of formic acid (HCOOH) on the Pd (1 1 1) transition metal surface is imperative for harnessing hydrogen energy. Despite a multitude of studies, the major mechanisms and key intermediates involved in the dehydrogenation process of formic acid remain a great topic of debate due to ambiguous adsorbate interactions. In this research, we develop an advanced microkinetic model based on first-principles calculations, accounting for adsorbate–adsorbate interactions. Our study unveils a comprehensive mechanism for the Pd (1 1 1) surface, highlighting the significance of coverage effects in formic acid dehydrogenation. Our findings unequivocally demonstrate that H coverage on the Pd (1 1 1) surface renders formic acid more susceptible to decompose into H2 and CO2 through COOH intermediates. Consistent with experimental results, the selectivity of H2 in the decomposition of formic acid on the Pd (1 1 1) surface approaches 100 %. Considering the influence of H coverage, our kinetic analysis aligns perfectly with experimental values at a temperature of 373 K.
AU - Yao, Zihao
AU - Liu, Xu
AU - Bunting, Rhys
AU - Wang, Jianguo
ID - 15114
JF - Chemical Engineering Science
SN - 0009-2509
TI - Unravelling the reaction mechanism for H2 production via formic acid decomposition over Pd: Coverage-dependent microkinetic modeling
VL - 291
ER -
TY - JOUR
AB - Thermoelectric materials convert heat into electricity, with a broad range of applications near room temperature (RT). However, the library of RT high-performance materials is limited. Traditional high-temperature synthetic methods constrain the range of materials achievable, hindering the ability to surpass crystal structure limitations and engineer defects. Here, a solution-based synthetic approach is introduced, enabling RT synthesis of powders and exploration of densification at lower temperatures to influence the material's microstructure. The approach is exemplified by Ag2Se, an n-type alternative to bismuth telluride. It is demonstrated that the concentration of Ag interstitials, grain boundaries, and dislocations are directly correlated to the sintering temperature, and achieve a figure of merit of 1.1 from RT to 100 °C after optimization. Moreover, insights into and resolve Ag2Se's challenges are provided, including stoichiometry issues leading to irreproducible performances. This work highlights the potential of RT solution synthesis in expanding the repertoire of high-performance thermoelectric materials for practical applications.
AU - Kleinhanns, Tobias
AU - Milillo, Francesco
AU - Calcabrini, Mariano
AU - Fiedler, Christine
AU - Horta, Sharona
AU - Balazs, Daniel
AU - Strumolo, Marissa J.
AU - Hasler, Roger
AU - Llorca, Jordi
AU - Tkadletz, Michael
AU - Brutchey, Richard L.
AU - Ibáñez, Maria
ID - 15182
JF - Advanced Energy Materials
SN - 1614-6832
TI - A route to high thermoelectric performance: Solution‐based control of microstructure and composition in Ag2Se
ER -
TY - JOUR
AB - Reducing defects boosts room-temperature performance of a thermoelectric device
AU - Navita, Navita
AU - Ibáñez, Maria
ID - 15166
IS - 6688
JF - Science
SN - 0036-8075
TI - Electron highways are cooler
VL - 383
ER -
TY - JOUR
AB - The development of cost-effective, high-activity and stable bifunctional catalysts for the oxygen reduction and evolution reactions (ORR/OER) is essential for zinc–air batteries (ZABs) to reach the market. Such catalysts must contain multiple adsorption/reaction sites to cope with the high demands of reversible oxygen electrodes. Herein, we propose a high entropy alloy (HEA) based on relatively abundant elements as a bifunctional ORR/OER catalyst. More specifically, we detail the synthesis of a CrMnFeCoNi HEA through a low-temperature solution-based approach. Such HEA displays superior OER performance with an overpotential of 265 mV at a current density of 10 mA/cm2, and a 37.9 mV/dec Tafel slope, well above the properties of a standard commercial catalyst based on RuO2. This high performance is partially explained by the presence of twinned defects, the incidence of large lattice distortions, and the electronic synergy between the different components, being Cr key to decreasing the energy barrier of the OER rate-determining step. CrMnFeCoNi also displays superior ORR performance with a half-potential of 0.78 V and an onset potential of 0.88 V, comparable with commercial Pt/C. The potential gap (Egap) between the OER overpotential and the ORR half-potential of CrMnFeCoNi is just 0.734 V. Taking advantage of these outstanding properties, ZABs are assembled using the CrMnFeCoNi HEA as air cathode and a zinc foil as the anode. The assembled cells provide an open-circuit voltage of 1.489 V, i.e. 90% of its theoretical limit (1.66 V), a peak power density of 116.5 mW/cm2, and a specific capacity of 836 mAh/g that stays stable for more than 10 days of continuous cycling, i.e. 720 cycles @ 8 mA/cm2 and 16.6 days of continuous cycling, i.e. 1200 cycles @ 5 mA/cm2.
AU - He, Ren
AU - Yang, Linlin
AU - Zhang, Yu
AU - Wang, Xiang
AU - Lee, Seungho
AU - Zhang, Ting
AU - Li, Lingxiao
AU - Liang, Zhifu
AU - Chen, Jingwei
AU - Li, Junshan
AU - Ostovari Moghaddam, Ahmad
AU - Llorca, Jordi
AU - Ibáñez, Maria
AU - Arbiol, Jordi
AU - Xu, Ying
AU - Cabot, Andreu
ID - 12832
IS - 4
JF - Energy Storage Materials
TI - A CrMnFeCoNi high entropy alloy boosting oxygen evolution/reduction reactions and zinc-air battery performance
VL - 58
ER -
TY - JOUR
AB - There is a need for the development of lead-free thermoelectric materials for medium-/high-temperature applications. Here, we report a thiol-free tin telluride (SnTe) precursor that can be thermally decomposed to produce SnTe crystals with sizes ranging from tens to several hundreds of nanometers. We further engineer SnTe–Cu2SnTe3 nanocomposites with a homogeneous phase distribution by decomposing the liquid SnTe precursor containing a dispersion of Cu1.5Te colloidal nanoparticles. The presence of Cu within the SnTe and the segregated semimetallic Cu2SnTe3 phase effectively improves the electrical conductivity of SnTe while simultaneously reducing the lattice thermal conductivity without compromising the Seebeck coefficient. Overall, power factors up to 3.63 mW m–1 K–2 and thermoelectric figures of merit up to 1.04 are obtained at 823 K, which represent a 167% enhancement compared with pristine SnTe.
AU - Nan, Bingfei
AU - Song, Xuan
AU - Chang, Cheng
AU - Xiao, Ke
AU - Zhang, Yu
AU - Yang, Linlin
AU - Horta, Sharona
AU - Li, Junshan
AU - Lim, Khak Ho
AU - Ibáñez, Maria
AU - Cabot, Andreu
ID - 13092
IS - 19
JF - ACS Applied Materials and Interfaces
SN - 1944-8244
TI - Bottom-up synthesis of SnTe-based thermoelectric composites
VL - 15
ER -
TY - JOUR
AB - The direct, solid state, and reversible conversion between heat and electricity using thermoelectric devices finds numerous potential uses, especially around room temperature. However, the relatively high material processing cost limits their real applications. Silver selenide (Ag2Se) is one of the very few n-type thermoelectric (TE) materials for room-temperature applications. Herein, we report a room temperature, fast, and aqueous-phase synthesis approach to produce Ag2Se, which can be extended to other metal chalcogenides. These materials reach TE figures of merit (zT) of up to 0.76 at 380 K. To improve these values, bismuth sulfide (Bi2S3) particles also prepared in an aqueous solution are incorporated into the Ag2Se matrix. In this way, a series of Ag2Se/Bi2S3 composites with Bi2S3 wt % of 0.5, 1.0, and 1.5 are prepared by solution blending and hot-press sintering. The presence of Bi2S3 significantly improves the Seebeck coefficient and power factor while at the same time decreasing the thermal conductivity with no apparent drop in electrical conductivity. Thus, a maximum zT value of 0.96 is achieved in the composites with 1.0 wt % Bi2S3 at 370 K. Furthermore, a high average zT value (zTave) of 0.93 in the 300–390 K range is demonstrated.
AU - Nan, Bingfei
AU - Li, Mengyao
AU - Zhang, Yu
AU - Xiao, Ke
AU - Lim, Khak Ho
AU - Chang, Cheng
AU - Han, Xu
AU - Zuo, Yong
AU - Li, Junshan
AU - Arbiol, Jordi
AU - Llorca, Jordi
AU - Ibáñez, Maria
AU - Cabot, Andreu
ID - 13093
JF - ACS Applied Electronic Materials
TI - Engineering of thermoelectric composites based on silver selenide in aqueous solution and ambient temperature
ER -
TY - JOUR
AB - AgSbSe2 is a promising thermoelectric (TE) p-type material for applications in the middle-temperature range. AgSbSe2 is characterized by relatively low thermal conductivities and high Seebeck coefficients, but its main limitation is moderate electrical conductivity. Herein, we detail an efficient and scalable hot-injection synthesis route to produce AgSbSe2 nanocrystals (NCs). To increase the carrier concentration and improve the electrical conductivity, these NCs are doped with Sn2+ on Sb3+ sites. Upon processing, the Sn2+ chemical state is conserved using a reducing NaBH4 solution to displace the organic ligand and anneal the material under a forming gas flow. The TE properties of the dense materials obtained from the consolidation of the NCs using a hot pressing are then characterized. The presence of Sn2+ ions replacing Sb3+ significantly increases the charge carrier concentration and, consequently, the electrical conductivity. Opportunely, the measured Seebeck coefficient varied within a small range upon Sn doping. The excellent performance obtained when Sn2+ ions are prevented from oxidation is rationalized by modeling the system. Calculated band structures disclosed that Sn doping induces convergence of the AgSbSe2 valence bands, accounting for an enhanced electronic effective mass. The dramatically enhanced carrier transport leads to a maximized power factor for AgSb0.98Sn0.02Se2 of 0.63 mW m–1 K–2 at 640 K. Thermally, phonon scattering is significantly enhanced in the NC-based materials, yielding an ultralow thermal conductivity of 0.3 W mK–1 at 666 K. Overall, a record-high figure of merit (zT) is obtained at 666 K for AgSb0.98Sn0.02Se2 at zT = 1.37, well above the values obtained for undoped AgSbSe2, at zT = 0.58 and state-of-art Pb- and Te-free materials, which makes AgSb0.98Sn0.02Se2 an excellent p-type candidate for medium-temperature TE applications.
AU - Liu, Yu
AU - Li, Mingquan
AU - Wan, Shanhong
AU - Lim, Khak Ho
AU - Zhang, Yu
AU - Li, Mengyao
AU - Li, Junshan
AU - Ibáñez, Maria
AU - Hong, Min
AU - Cabot, Andreu
ID - 13235
IS - 12
JF - ACS Nano
SN - 1936-0851
TI - Surface chemistry and band engineering in AgSbSe₂: Toward high thermoelectric performance
VL - 17
ER -
TY - THES
AB - High-performance semiconductors rely upon precise control of heat and charge transport. This can be achieved by precisely engineering defects in polycrystalline solids. There are multiple approaches to preparing such polycrystalline semiconductors, and the transformation of solution-processed colloidal nanoparticles is appealing because colloidal nanoparticles combine low cost with structural and compositional tunability along with rich surface chemistry. However, the multiple processes from nanoparticle synthesis to the final bulk nanocomposites are very complex. They involve nanoparticle purification, post-synthetic modifications, and finally consolidation (thermal treatments and densification). All these properties dictate the final material’s composition and microstructure, ultimately affecting its functional properties. This thesis explores the synthesis, surface chemistry and consolidation of colloidal semiconductor nanoparticles into dense solids. In particular, the transformations that take place during these processes, and their effect on the material’s transport properties are evaluated.
AU - Calcabrini, Mariano
ID - 12885
SN - 2663-337X
TI - Nanoparticle-based semiconductor solids: From synthesis to consolidation
ER -
TY - JOUR
AB - The power factor of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) film can be significantly improved by optimizing the oxidation level of the film in oxidation and reduction processes. However, precise control over the oxidation and reduction effects in PEDOT:PSS remains a challenge, which greatly sacrifices both S and σ. Here, we propose a two-step post-treatment using a mixture of ethylene glycol (EG) and Arginine (Arg) and sulfuric acid (H2SO4) in sequence to engineer high-performance PEDOT:PSS thermoelectric films. The high-polarity EG dopant removes the excess non-ionized PSS and induces benzenoid-to-quinoid conformational change in the PEDOT:PSS films. In particular, basic amino acid Arg tunes the oxidation level of PEDOT:PSS and prevents the films from over-oxidation during H2SO4 post-treatment, leading to increased S. The following H2SO4 post-treatment further induces highly orientated lamellar stacking microstructures to increase σ, yielding a maximum power factor of 170.6 μW m−1 K−2 at 460 K. Moreover, a novel trigonal-shape thermoelectric device is designed and assembled by the as-prepared PEDOT:PSS films in order to harvest heat via a vertical temperature gradient. An output power density of 33 μW cm−2 is generated at a temperature difference of 40 K, showing the potential application for low-grade wearable electronic devices.
AU - Zhang, Li
AU - Liu, Xingyu
AU - Wu, Ting
AU - Xu, Shengduo
AU - Suo, Guoquan
AU - Ye, Xiaohui
AU - Hou, Xiaojiang
AU - Yang, Yanling
AU - Liu, Qingfeng
AU - Wang, Hongqiang
ID - 12113
JF - Applied Surface Science
KW - Surfaces
KW - Coatings and Films
KW - Condensed Matter Physics
KW - Surfaces and Interfaces
KW - General Physics and Astronomy
KW - General Chemistry
SN - 0169-4332
TI - Two-step post-treatment to deliver high performance thermoelectric device with vertical temperature gradient
VL - 613
ER -
TY - JOUR
AB - High carrier mobility is critical to improving thermoelectric performance over a broad temperature range. However, traditional doping inevitably deteriorates carrier mobility. Herein, we develop a strategy for fine tuning of defects to improve carrier mobility. To begin, n-type PbTe is created by compensating for the intrinsic Pb vacancy in bare PbTe. Excess Pb2+ reduces vacancy scattering, resulting in a high carrier mobility of ∼3400 cm2 V–1 s–1. Then, excess Ag is introduced to compensate for the remaining intrinsic Pb vacancies. We find that excess Ag exhibits a dynamic doping process with increasing temperatures, increasing both the carrier concentration and carrier mobility throughout a wide temperature range; specifically, an ultrahigh carrier mobility ∼7300 cm2 V–1 s–1 is obtained for Pb1.01Te + 0.002Ag at 300 K. Moreover, the dynamic doping-induced high carrier concentration suppresses the bipolar thermal conductivity at high temperatures. The final step is using iodine to optimize the carrier concentration to ∼1019 cm–3. Ultimately, a maximum ZT value of ∼1.5 and a large average ZTave value of ∼1.0 at 300–773 K are obtained for Pb1.01Te0.998I0.002 + 0.002Ag. These findings demonstrate that fine tuning of defects with <0.5% impurities can remarkably enhance carrier mobility and improve thermoelectric performance.
AU - Wang, Siqi
AU - Chang, Cheng
AU - Bai, Shulin
AU - Qin, Bingchao
AU - Zhu, Yingcai
AU - Zhan, Shaoping
AU - Zheng, Junqing
AU - Tang, Shuwei
AU - Zhao, Li Dong
ID - 12331
IS - 2
JF - Chemistry of Materials
SN - 0897-4756
TI - Fine tuning of defects enables high carrier mobility and enhanced thermoelectric performance of n-type PbTe
VL - 35
ER -
TY - JOUR
AB - Cu2–xS and Cu2–xSe have recently been reported as promising thermoelectric (TE) materials for medium-temperature applications. In contrast, Cu2–xTe, another member of the copper chalcogenide family, typically exhibits low Seebeck coefficients that limit its potential to achieve a superior thermoelectric figure of merit, zT, particularly in the low-temperature range where this material could be effective. To address this, we investigated the TE performance of Cu1.5–xTe–Cu2Se nanocomposites by consolidating surface-engineered Cu1.5Te nanocrystals. This surface engineering strategy allows for precise adjustment of Cu/Te ratios and results in a reversible phase transition at around 600 K in Cu1.5–xTe–Cu2Se nanocomposites, as systematically confirmed by in situ high-temperature X-ray diffraction combined with differential scanning calorimetry analysis. The phase transition leads to a conversion from metallic-like to semiconducting-like TE properties. Additionally, a layer of Cu2Se generated around Cu1.5–xTe nanoparticles effectively inhibits Cu1.5–xTe grain growth, minimizing thermal conductivity and decreasing hole concentration. These properties indicate that copper telluride based compounds have a promising thermoelectric potential, translated into a high dimensionless zT of 1.3 at 560 K.
AU - Xing, Congcong
AU - Zhang, Yu
AU - Xiao, Ke
AU - Han, Xu
AU - Liu, Yu
AU - Nan, Bingfei
AU - Ramon, Maria Garcia
AU - Lim, Khak Ho
AU - Li, Junshan
AU - Arbiol, Jordi
AU - Poudel, Bed
AU - Nozariasbmarz, Amin
AU - Li, Wenjie
AU - Ibáñez, Maria
AU - Cabot, Andreu
ID - 12915
IS - 9
JF - ACS Nano
SN - 1936-0851
TI - Thermoelectric performance of surface-engineered Cu1.5–xTe–Cu2Se nanocomposites
VL - 17
ER -
TY - JOUR
AB - The deployment of direct formate fuel cells (DFFCs) relies on the development of active and stable catalysts for the formate oxidation reaction (FOR). Palladium, providing effective full oxidation of formate to CO2, has been widely used as FOR catalyst, but it suffers from low stability, moderate activity, and high cost. Herein, we detail a colloidal synthesis route for the incorporation of P on Pd2Sn nanoparticles. These nanoparticles are dispersed on carbon black and the obtained composite is used as electrocatalytic material for the FOR. The Pd2Sn0.8P-based electrodes present outstanding catalytic activities with record mass current densities up to 10.0 A mgPd-1, well above those of Pd1.6Sn/C reference electrode. These high current densities are further enhanced by increasing the temperature from 25 °C to 40 °C. The Pd2Sn0.8P electrode also allows for slowing down the rapid current decay that generally happens during operation and can be rapidly re-activated through potential cycling. The excellent catalytic performance obtained is rationalized using density functional theory (DFT) calculations.
AU - Montaña-Mora, Guillem
AU - Qi, Xueqiang
AU - Wang, Xiang
AU - Chacón-Borrero, Jesus
AU - Martinez-Alanis, Paulina R.
AU - Yu, Xiaoting
AU - Li, Junshan
AU - Xue, Qian
AU - Arbiol, Jordi
AU - Ibáñez, Maria
AU - Cabot, Andreu
ID - 12829
JF - Journal of Electroanalytical Chemistry
SN - 1572-6657
TI - Phosphorous incorporation into palladium tin nanoparticles for the electrocatalytic formate oxidation reaction
VL - 936
ER -
TY - JOUR
AB - A light-triggered fabrication method extends the functionality of printable nanomaterials
AU - Balazs, Daniel
AU - Ibáñez, Maria
ID - 14404
IS - 6665
JF - Science
TI - Widening the use of 3D printing
VL - 381
ER -
TY - JOUR
AB - Physical catalysts often have multiple sites where reactions can take place. One prominent example is single-atom alloys, where the reactive dopant atoms can preferentially locate in the bulk or at different sites on the surface of the nanoparticle. However, ab initio modeling of catalysts usually only considers one site of the catalyst, neglecting the effects of multiple sites. Here, nanoparticles of copper doped with single-atom rhodium or palladium are modeled for the dehydrogenation of propane. Single-atom alloy nanoparticles are simulated at 400–600 K, using machine learning potentials trained on density functional theory calculations, and then the occupation of different single-atom active sites is identified using a similarity kernel. Further, the turnover frequency for all possible sites is calculated for propane dehydrogenation to propene through microkinetic modeling using density functional theory calculations. The total turnover frequencies of the whole nanoparticle are then described from both the population and the individual turnover frequency of each site. Under operating conditions, rhodium as a dopant is found to almost exclusively occupy (111) surface sites while palladium as a dopant occupies a greater variety of facets. Undercoordinated dopant surface sites are found to tend to be more reactive for propane dehydrogenation compared to the (111) surface. It is found that considering the dynamics of the single-atom alloy nanoparticle has a profound effect on the calculated catalytic activity of single-atom alloys by several orders of magnitude.
AU - Bunting, Rhys
AU - Wodaczek, Felix
AU - Torabi, Tina
AU - Cheng, Bingqing
ID - 13216
IS - 27
JF - Journal of the American Chemical Society
KW - Colloid and Surface Chemistry
KW - Biochemistry
KW - General Chemistry
KW - Catalysis
SN - 0002-7863
TI - Reactivity of single-atom alloy nanoparticles: Modeling the dehydrogenation of propane
VL - 145
ER -
TY - JOUR
AB - As a bottleneck in the direct synthesis of hydrogen peroxide, the development of an efficient palladium-based catalyst has garnered great attention. However, elusive active centers and reaction mechanism issues inhibit further optimization of its performance. In this work, advanced microkinetic modeling with the adsorbate–adsorbate interaction and nanoparticle size effect based on first-principles calculations is developed. A full mechanism uncovering the significance of adsorbate–adsorbate interaction is determined on Pd nanoparticles. We demonstrate unambiguously that Pd(100) with main coverage species of O2 and H is beneficial to H2O2 production, being consistent with experimental operando observation, while H2O forms on Pd(111) covered by O species and Pd(211) covered by O and OH species. Kinetic analyses further enable quantitative estimation of the influence of temperature, pressure, and particle size. Large-size Pd nanoparticles are found to achieve a high H2O2 reaction rate when the operating conditions are moderate temperature and higher oxygen partial pressure. We reveal that specific facets of the Pd nanoparticles are crucial factors for their selectivity and activity. Consistent with the experiment, the production of H2O2 is discovered to be more favorable on Pd nanoparticles containing Pd(100) facets. The ratio of H2/O2 induces substantial variations in the coverage of intermediates of O2 and H on Pd(100), resulting in a change in product selectivity.
AU - Zhao, Jinyan
AU - Yao, Zihao
AU - Bunting, Rhys
AU - Hu, P.
AU - Wang, Jianguo
ID - 14663
IS - 22
JF - ACS Catalysis
TI - Microkinetic modeling with size-dependent and adsorbate-adsorbate interactions for the direct synthesis of H₂O₂ over Pd nanoparticles
VL - 13
ER -
TY - JOUR
AB - In order to demonstrate the stability of newly proposed iridium-based Ir2Cr(In,Sn) and IrRhCr(In,Sn) heusler alloys, we present ab-initio analysis of these alloys by examining various properties to prove their stability. The stability of these alloys can be inferred from different cohesive and formation energies as well as positive phonon frequencies. Their electronic structure results indicate that they are semi-metals in nature. The magnetic moments are computed using the Slater-Pauling formula and exhibit a high value, with the Cr atom contributing the most in all alloys. Mulliken’s charge analysis results show that our alloys contain a range of linkages, mainly ionic and covalent ones. The ductility and mechanical stability of these alloys are confirmed by elastic constants viz. Poisson’s ratio, Pugh’s ratio, and many different types of elastic moduli.
AU - Gupta, Shyam Lal
AU - Singh, Saurabh
AU - Kumar, Sumit
AU - Anupam, Unknown
AU - Thakur, Samjeet Singh
AU - Kumar, Ashish
AU - Panwar, Sanjay
AU - Diwaker, D.
ID - 14652
JF - Physica B: Condensed Matter
SN - 0921-4526
TI - Ab-initio stability of Iridium based newly proposed full and quaternary heusler alloys
VL - 674
ER -
TY - JOUR
AB - The use of multimodal readout mechanisms next to label-free real-time monitoring of biomolecular interactions can provide valuable insight into surface-based reaction mechanisms. To this end, the combination of an electrolyte-gated field-effect transistor (EG-FET) with a fiber optic-coupled surface plasmon resonance (FO-SPR) probe serving as gate electrode has been investigated to deconvolute surface mass and charge density variations associated to surface reactions. However, applying an electrochemical potential on such gold-coated FO-SPR gate electrodes can induce gradual morphological changes of the thin gold film, leading to an irreversible blue-shift of the SPR wavelength and a substantial signal drift. We show that mild annealing leads to optical and electronic signal stabilization (20-fold lower signal drift than as-sputtered fiber optic gates) and improved overall analytical performance characteristics. The thermal treatment prevents morphological changes of the thin gold-film occurring during operation, hence providing reliable and stable data immediately upon gate voltage application. Thus, the readout output of both transducing principles, the optical FO-SPR and electronic EG-FET, stays constant throughout the whole sensing time-window and the long-term effect of thermal treatment is also improved, providing stable signals even after 1 year of storage. Annealing should therefore be considered a necessary modification for applying fiber optic gate electrodes in real-time multimodal investigations of surface reactions at the solid-liquid interface.
AU - Hasler, Roger
AU - Steger-Polt, Marie Helene
AU - Reiner-Rozman, Ciril
AU - Fossati, Stefan
AU - Lee, Seungho
AU - Aspermair, Patrik
AU - Kleber, Christoph
AU - Ibáñez, Maria
AU - Dostalek, Jakub
AU - Knoll, Wolfgang
ID - 13968
JF - Frontiers in Physics
TI - Optical and electronic signal stabilization of plasmonic fiber optic gate electrodes: Towards improved real-time dual-mode biosensing
VL - 11
ER -
TY - JOUR
AB - High entropy alloys (HEAs) are highly suitable candidate catalysts for oxygen evolution and reduction reactions (OER/ORR) as they offer numerous parameters for optimizing the electronic structure and catalytic sites. Herein, FeCoNiMoW HEA nanoparticles are synthesized using a solution‐based low‐temperature approach. Such FeCoNiMoW nanoparticles show high entropy properties, subtle lattice distortions, and modulated electronic structure, leading to superior OER performance with an overpotential of 233 mV at 10 mA cm−2 and 276 mV at 100 mA cm−2. Density functional theory calculations reveal the electronic structures of the FeCoNiMoW active sites with an optimized d‐band center position that enables suitable adsorption of OOH* intermediates and reduces the Gibbs free energy barrier in the OER process. Aqueous zinc–air batteries (ZABs) based on this HEA demonstrate a high open circuit potential of 1.59 V, a peak power density of 116.9 mW cm−2, a specific capacity of 857 mAh gZn−1, and excellent stability for over 660 h of continuous charge–discharge cycles. Flexible and solid ZABs are also assembled and tested, displaying excellent charge–discharge performance at different bending angles. This work shows the significance of 4d/5d metal‐modulated electronic structure and optimized adsorption ability to improve the performance of OER/ORR, ZABs, and beyond.
AU - He, Ren
AU - Yang, Linlin
AU - Zhang, Yu
AU - Jiang, Daochuan
AU - Lee, Seungho
AU - Horta, Sharona
AU - Liang, Zhifu
AU - Lu, Xuan
AU - Ostovari Moghaddam, Ahmad
AU - Li, Junshan
AU - Ibáñez, Maria
AU - Xu, Ying
AU - Zhou, Yingtang
AU - Cabot, Andreu
ID - 14434
JF - Advanced Materials
KW - Mechanical Engineering
KW - Mechanics of Materials
KW - General Materials Science
SN - 0935-9648
TI - A 3d‐4d‐5d high entropy alloy as a bifunctional oxygen catalyst for robust aqueous zinc–air batteries
ER -
TY - JOUR
AB - Low‐cost, safe, and environmental‐friendly rechargeable aqueous zinc‐ion batteries (ZIBs) are promising as next‐generation energy storage devices for wearable electronics among other applications. However, sluggish ionic transport kinetics and the unstable electrode structure during ionic insertion/extraction hampers their deployment. Herein, we propose a new cathode material based on a layered metal chalcogenide (LMC), bismuth telluride (Bi2Te3), coated with polypyrrole (PPy). Taking advantage of the PPy coating, the Bi2Te3@PPy composite presents strong ionic absorption affinity, high oxidation resistance, and high structural stability. The ZIBs based on Bi2Te3@PPy cathodes exhibit high capacities and ultra‐long lifespans of over 5000 cycles. They also present outstanding stability even under bending. In addition, we analyze here the reaction mechanism using in situ X‐ray diffraction, X‐ray photoelectron spectroscopy, and computational tools and demonstrate that, in the aqueous system, Zn2+ is not inserted into the cathode as previously assumed. In contrast, proton charge storage dominates the process. Overall, this work not only shows the great potential of LMCs as ZIBs cathode materials and the advantages of PPy coating, but also clarifies the charge/discharge mechanism in rechargeable ZIBs based on LMCs.
AU - Zeng, Guifang
AU - Sun, Qing
AU - Horta, Sharona
AU - Wang, Shang
AU - Lu, Xuan
AU - Zhang, Chaoyue
AU - Li, Jing
AU - Li, Junshan
AU - Ci, Lijie
AU - Tian, Yanhong
AU - Ibáñez, Maria
AU - Cabot, Andreu
ID - 14435
JF - Advanced Materials
KW - Mechanical Engineering
KW - Mechanics of Materials
KW - General Materials Science
SN - 0935-9648
TI - A layered Bi2Te3@PPy cathode for aqueous zinc ion batteries: Mechanism and application in printed flexible batteries
ER -
TY - JOUR
AB - Lithium–sulfur batteries are regarded as an advantageous option for meeting the growing demand for high-energy-density storage, but their commercialization relies on solving the current limitations of both sulfur cathodes and lithium metal anodes. In this scenario, the implementation of lithium sulfide (Li2S) cathodes compatible with alternative anode materials such as silicon has the potential to alleviate the safety concerns associated with lithium metal. In this direction, here, we report a sulfur cathode based on Li2S nanocrystals grown on a catalytic host consisting of CoFeP nanoparticles supported on tubular carbon nitride. Nanosized Li2S is incorporated into the host by a scalable liquid infiltration–evaporation method. Theoretical calculations and experimental results demonstrate that the CoFeP–CN composite can boost the polysulfide adsorption/conversion reaction kinetics and strongly reduce the initial overpotential activation barrier by stretching the Li–S bonds of Li2S. Besides, the ultrasmall size of the Li2S particles in the Li2S–CoFeP–CN composite cathode facilitates the initial activation. Overall, the Li2S–CoFeP–CN electrodes exhibit a low activation barrier of 2.56 V, a high initial capacity of 991 mA h gLi2S–1, and outstanding cyclability with a small fading rate of 0.029% per cycle over 800 cycles. Moreover, Si/Li2S full cells are assembled using the nanostructured Li2S–CoFeP–CN cathode and a prelithiated anode based on graphite-supported silicon nanowires. These Si/Li2S cells demonstrate high initial discharge capacities above 900 mA h gLi2S–1 and good cyclability with a capacity fading rate of 0.28% per cycle over 150 cycles.
AU - Mollania, Hamid
AU - Zhang, Chaoqi
AU - Du, Ruifeng
AU - Qi, Xueqiang
AU - Li, Junshan
AU - Horta, Sharona
AU - Ibáñez, Maria
AU - Keller, Caroline
AU - Chenevier, Pascale
AU - Oloomi-Buygi, Majid
AU - Cabot, Andreu
ID - 14719
IS - 50
JF - ACS Applied Materials and Interfaces
SN - 1944-8244
TI - Nanostructured Li₂S cathodes for silicon-sulfur batteries
VL - 15
ER -
TY - JOUR
AB - Developing cost-effective and high-performance thermoelectric (TE) materials to assemble efficient TE devices presents a multitude of challenges and opportunities. Cu3SbSe4 is a promising p-type TE material based on relatively earth abundant elements. However, the challenge lies in its poor electrical conductivity. Herein, an efficient and scalable solution-based approach is developed to synthesize high-quality Cu3SbSe4 nanocrystals doped with Pb at the Sb site. After ligand displacement and annealing treatments, the dried powders are consolidated into dense pellets, and their TE properties are investigated. Pb doping effectively increases the charge carrier concentration, resulting in a significant increase in electrical conductivity, while the Seebeck coefficients remain consistently high. The calculated band structure shows that Pb doping induces band convergence, thereby increasing the effective mass. Furthermore, the large ionic radius of Pb2+ results in the generation of additional point and plane defects and interphases, dramatically enhancing phonon scattering, which significantly decreases the lattice thermal conductivity at high temperatures. Overall, a maximum figure of merit (zTmax) ≈ 0.85 at 653 K is obtained in Cu3Sb0.97Pb0.03Se4. This represents a 1.6-fold increase compared to the undoped sample and exceeds most doped Cu3SbSe4-based materials produced by solid-state, demonstrating advantages of versatility and cost-effectiveness using a solution-based technology.
AU - Wan, Shanhong
AU - Xiao, Shanshan
AU - Li, Mingquan
AU - Wang, Xin
AU - Lim, Khak Ho
AU - Hong, Min
AU - Ibáñez, Maria
AU - Cabot, Andreu
AU - Liu, Yu
ID - 14734
JF - Small Methods
TI - Band engineering through Pb-doping of nanocrystal building blocks to enhance thermoelectric performance in Cu3SbSe4
ER -
TY - JOUR
AB - The effects of the partial V-substitution for Ag on the thermoelectric (TE) properties are investigated for a flexible semiconducting compound Ag2S0.55Se0.45. Density functional theory calculations predict that such a partial V-substitution constructively modifies the electronic structure near the bottom of the conduction band to improve the TE performance. The synthesized Ag1.97V0.03S0.55Se0.45 is found to possess a TE dimensionless figure-of-merit (ZT) of 0.71 at 350 K with maintaining its flexible nature. This ZT value is relatively high in comparison with those reported for flexible TE materials below 360 K. The increase in the ZT value is caused by the enhanced absolute value of the Seebeck coefficient with less significant variation in electrical resistivity. The high ZT value with the flexible nature naturally allows us to employ the Ag1.97V0.03S0.55Se0.45 as a component of flexible TE generators.
AU - Sato, Kosuke
AU - Singh, Saurabh
AU - Yamazaki, Itsuki
AU - Hirata, Keisuke
AU - Ang, Artoni Kevin R.
AU - Matsunami, Masaharu
AU - Takeuchi, Tsunehiro
ID - 14777
IS - 12
JF - AIP Advances
KW - General Physics and Astronomy
TI - Improvement of thermoelectric performance of flexible compound Ag2S0.55Se0.45 by means of partial V-substitution for Ag
VL - 13
ER -
TY - JOUR
AB - We report on a simple surfactant/template free chemical route for the synthesis of semi-polycrystalline polyaniline-graphite (SPani-graphite) composite and its application as an electroactive material in electrochemical charge storage. The synthesized material exhibits well-defined poly-crystallographic lattices in high resolution transmission electron micrographs and sharp peaks in x-ray diffraction spectra suggesting crystalline nature of the material. The specific capacitance computed from the galvanostatic charge-discharge (GCD) data obtained from 3-electrode cell configuration using 1 M aq. Na2SO4 as an electrolyte was 111.4 F g−1 at a current density of 0.1 A g−1 which rises to 269 F g−1 at an elevated current density of 1.0 A g−1. A similar pattern of increase in the specific capacitance values with an increase in the current density was observed in the results obtained from 2-electrode symmetric device configuration using polymer gel electrolyte (xanthan gum in 1 M aq. Na2SO4). The specific capacitance computed from the GCD data obtained from the device configuration was 20 F g−1 at the current density of 1.0 A g−1. The device delivers an energy density of 1.7 Wh kg−1 and a power density of 2.48 kWh kg−1 at an applied current density of 0.5 A g−1 suggesting an excellent rate capability and power management. In addition, the device exhibits ⁓92 % specific capacitance retention up to 8000 continuous GCD cycles and ⁓80 % coulombic efficiency up to 10,000 continuous GCD cycles indicating excellent cycling stability. The unique feature of increasing specific capacitance with respect to applied current density is attributed to the presence of semi-polycrystalline phases in the SPani-graphite matrix. The material behaves as a surface redox supercapacitor and its unique mechanism of charge storage is discussed in detail in the article.
AU - Mahato, Neelima
AU - Singh, Saurabh
AU - Faisal, Mohammad
AU - Sreekanth, T. V.M.
AU - Majumder, Sutripto
AU - Yoo, Kisoo
AU - Kim, Jonghoon
ID - 14379
JF - Synthetic Metals
SN - 0379-6779
TI - Polycrystalline phases grown in-situ engendering unique mechanism of charge storage in polyaniline-graphite composite
VL - 299
ER -
TY - JOUR
AB - Lead sulfide (PbS) presents large potential in thermoelectric application due to its earth-abundant S element. However, its inferior average ZT (ZTave) value makes PbS less competitive with its analogs PbTe and PbSe. To promote its thermoelectric performance, this study implements strategies of continuous Se alloying and Cu interstitial doping to synergistically tune thermal and electrical transport properties in n-type PbS. First, the lattice parameter of 5.93 Å in PbS is linearly expanded to 6.03 Å in PbS0.5Se0.5 with increasing Se alloying content. This expanded lattice in Se-alloyed PbS not only intensifies phonon scattering but also facilitates the formation of Cu interstitials. Based on the PbS0.6Se0.4 content with the minimal lattice thermal conductivity, Cu interstitials are introduced to improve the electron density, thus boosting the peak power factor, from 3.88 μW cm−1 K−2 in PbS0.6Se0.4 to 20.58 μW cm−1 K−2 in PbS0.6Se0.4−1%Cu. Meanwhile, the lattice thermal conductivity in PbS0.6Se0.4−x%Cu (x = 0–2) is further suppressed due to the strong strain field caused by Cu interstitials. Finally, with the lowered thermal conductivity and high electrical transport properties, a peak ZT ~1.1 and ZTave ~0.82 can be achieved in PbS0.6Se0.4 − 1%Cu at 300–773K, which outperforms previously reported n-type PbS.
AU - Liu, Zhengtao
AU - Hong, Tao
AU - Xu, Liqing
AU - Wang, Sining
AU - Gao, Xiang
AU - Chang, Cheng
AU - Ding, Xiangdong
AU - Xiao, Yu
AU - Zhao, Li‐Dong
ID - 14985
IS - 1
JF - Interdisciplinary Materials
TI - Lattice expansion enables interstitial doping to achieve a high average ZT in n‐type PbS
VL - 2
ER -
TY - JOUR
AB - Access to a blossoming library of colloidal nanomaterials provides building blocks for complex assembled materials. The journey to bring these prospects to fruition stands to benefit from the application of advanced processing methods. Epitaxially connected nanocrystal (or quantum dot) superlattices present a captivating model system for mesocrystals with intriguing emergent properties. The conventional processing approach to creating these materials involves assembling and attaching the constituent nanocrystals at the interface between two immiscible fluids. Processing small liquid volumes of the colloidal nanocrystal solution involves several complexities arising from the concurrent spreading, evaporation, assembly, and attachment. The ability of inkjet printers to deliver small (typically picoliter) liquid volumes with precise positioning is attractive to advance fundamental insights into the processing science, and thereby potentially enable new routes to incorporate the epitaxially connected superlattices into technology platforms. In this study, we identified the processing window of opportunity, including nanocrystal ink formulation and printing approach to enable delivery of colloidal nanocrystals from an inkjet nozzle onto the surface of a sessile droplet of the immiscible subphase. We demonstrate how inkjet printing can be scaled-down to enable the fabrication of epitaxially connected superlattices on patterned sub-millimeter droplets. We anticipate that insights from this work will spur on future advances to enable more mechanistic insights into the assembly processes and new avenues to create high-fidelity superlattices.
AU - Balazs, Daniel
AU - Erkan, N. Deniz
AU - Quien, Michelle
AU - Hanrath, Tobias
ID - 10587
IS - 5
JF - Nano Research
KW - interfacial assembly
KW - colloidal nanocrystal
KW - superlattice
KW - inkjet printing
SN - 1998-0124
TI - Inkjet printing of epitaxially connected nanocrystal superlattices
VL - 15
ER -
TY - JOUR
AB - SnSe has emerged as one of the most promising materials for thermoelectric energy conversion due to its extraordinary performance in its single-crystal form and its low-cost constituent elements. However, to achieve an economic impact, the polycrystalline counterpart needs to replicate the performance of the single crystal. Herein, we optimize the thermoelectric performance of polycrystalline SnSe produced by consolidating solution-processed and surface-engineered SnSe particles. In particular, the SnSe particles are coated with CdSe molecular complexes that crystallize during the sintering process, forming CdSe nanoparticles. The presence of CdSe nanoparticles inhibits SnSe grain growth during the consolidation step due to Zener pinning, yielding a material with a high density of grain boundaries. Moreover, the resulting SnSe–CdSe nanocomposites present a large number of defects at different length scales, which significantly reduce the thermal conductivity. The produced SnSe–CdSe nanocomposites exhibit thermoelectric figures of merit up to 2.2 at 786 K, which is among the highest reported for solution-processed SnSe.
AU - Liu, Yu
AU - Calcabrini, Mariano
AU - Yu, Yuan
AU - Lee, Seungho
AU - Chang, Cheng
AU - David, Jérémy
AU - Ghosh, Tanmoy
AU - Spadaro, Maria Chiara
AU - Xie, Chenyang
AU - Cojocaru-Mirédin, Oana
AU - Arbiol, Jordi
AU - Ibáñez, Maria
ID - 10042
IS - 1
JF - ACS Nano
KW - tin selenide
KW - nanocomposite
KW - grain growth
KW - Zener pinning
KW - thermoelectricity
KW - annealing
KW - solution processing
SN - 1936-0851
TI - Defect engineering in solution-processed polycrystalline SnSe leads to high thermoelectric performance
VL - 16
ER -
TY - JOUR
AB - A novel multivariable system, combining a transistor with fiber optic-based surface plasmon resonance spectroscopy with the gate electrode simultaneously acting as the fiber optic sensor surface, is reported. The dual-mode sensor allows for discrimination of mass and charge contributions for binding assays on the same sensor surface. Furthermore, we optimize the sensor geometry by investigating the influence of the fiber area to transistor channel area ratio and distance. We show that larger fiber optic tip diameters are favorable for electronic and optical signals and demonstrate the reversibility of plasmon resonance wavelength shifts after electric field application. As a proof of principle, a layer-by-layer assembly of polyelectrolytes is performed to benchmark the system against multivariable sensing platforms with planar surface plasmon resonance configurations. Furthermore, the biosensing performance is assessed using a thrombin binding assay with surface-immobilized aptamers as receptors, allowing for the detection of medically relevant thrombin concentrations.
AU - Hasler, Roger
AU - Reiner-Rozman, Ciril
AU - Fossati, Stefan
AU - Aspermair, Patrik
AU - Dostalek, Jakub
AU - Lee, Seungho
AU - Ibáñez, Maria
AU - Bintinger, Johannes
AU - Knoll, Wolfgang
ID - 10829
IS - 2
JF - ACS Sensors
TI - Field-effect transistor with a plasmonic fiber optic gate electrode as a multivariable biosensor device
VL - 7
ER -
TY - GEN
AB - Detailed information about the data set see "dataset description.txt" file.
AU - Hasler, Roger
AU - Reiner-Rozman, Ciril
AU - Fossati, Stefan
AU - Aspermair, Patrik
AU - Dostalek, Jakub
AU - Lee, Seungho
AU - Ibáñez, Maria
AU - Bintinger, Johannes
AU - Knoll, Wolfgang
ID - 10833
TI - Field-effect transistor with a plasmonic fiber optic gate electrode as a multivariable biosensor device
ER -
TY - JOUR
AB - SnTe is a promising Pb-free thermoelectric (TE) material with high electrical conductivity. We discovered the synergistic effect of Bi2O3 on enhancing the average power factor (PF) and overall ZT value of the SnTe-based thermoelectric material. The introduction of Bi2O3 forms plenty of SnO2, Bi2O3, and Bi-rich nanoprecipitates. These interfaces between the SnTe matrix and the nanoprecipitates can enhance the average PF through the energy filtering effect. On the other hand, abundant and diverse nanoprecipitates can significantly diminish the lattice thermal conductivity (κlat) through enhanced phonon scattering. The synergistic effect of Bi2O3 resulted in a maximum ZT (ZTmax) value of 0.9 at SnTe-2% Bi2O3 and an average ZT (ZTave) value of 0.4 for SnTe-4% Bi2O3 from 300 K to 823 K. The work provides an excellent reference to develop non-toxic high-performance TE materials.
AU - Hong, Tao
AU - Guo, Changrong
AU - Wang, Dongyang
AU - Qin, Bingchao
AU - Chang, Cheng
AU - Gao, Xiang
AU - Zhao, Li Dong
ID - 11142
JF - Materials Today Energy
TI - Enhanced thermoelectric performance in SnTe due to the energy filtering effect introduced by Bi2O3
VL - 25
ER -
TY - JOUR
AU - Chang, Cheng
AU - Qin, Bingchao
AU - Su, Lizhong
AU - Zhao, Li Dong
ID - 11356
IS - 11
JF - Science Bulletin
SN - 2095-9273
TI - Distinct electron and hole transports in SnSe crystals
VL - 67
ER -
TY - JOUR
AB - Tin selenide (SnSe) is considered a robust candidate for thermoelectric applications due to its very high thermoelectric figure of merit, ZT, with values of 2.6 in p-type and 2.8 in n-type single crystals. Sn has been replaced with various lower group dopants to achieve successful p-type doping in SnSe with high ZT values. A known, facile, and powerful alternative way to introduce a hole carrier is to use a natural single Sn vacancy, VSn. Through transport and scanning tunneling microscopy studies, we discovered that VSn are dominant in high-quality (slow cooling rate) SnSe single crystals, while multiple vacancies, Vmulti, are dominant in low-quality (high cooling rate) single crystals. Surprisingly, both VSn and Vmulti help to increase the power factors of SnSe, whereas samples with dominant VSn have superior thermoelectric properties in SnSe single crystals. Additionally, the observation that Vmulti are good p-type sources observed in relatively low-quality single crystals is useful in thermoelectric applications because polycrystalline SnSe can be used due to its mechanical strength; this substance is usually fabricated at very high cooling speeds.
AU - Nguyen, Van Quang
AU - Trinh, Thi Ly
AU - Chang, Cheng
AU - Zhao, Li Dong
AU - Nguyen, Thi Huong
AU - Duong, Van Thiet
AU - Duong, Anh Tuan
AU - Park, Jong Ho
AU - Park, Sudong
AU - Kim, Jungdae
AU - Cho, Sunglae
ID - 11401
JF - NPG Asia Materials
SN - 1884-4049
TI - Unidentified major p-type source in SnSe: Multivacancies
VL - 14
ER -
TY - JOUR
AB - The precursor conversion chemistry and surface chemistry of Cu3N and Cu3PdN nanocrystals are unknown or contested. Here, we first obtain phase-pure, colloidally stable nanocubes. Second, we elucidate the pathway by which copper(II) nitrate and oleylamine form Cu3N. We find that oleylamine is both a reductant and a nitrogen source. Oleylamine is oxidized by nitrate to a primary aldimine, which reacts further with excess oleylamine to a secondary aldimine, eliminating ammonia. Ammonia reacts with CuI to form Cu3N. Third, we investigated the surface chemistry and find a mixed ligand shell of aliphatic amines and carboxylates (formed in situ). While the carboxylates appear tightly bound, the amines are easily desorbed from the surface. Finally, we show that doping with palladium decreases the band gap and the material becomes semi-metallic. These results bring insight into the chemistry of metal nitrides and might help the development of other metal nitride nanocrystals.
AU - Parvizian, Mahsa
AU - Duràn Balsa, Alejandra
AU - Pokratath, Rohan
AU - Kalha, Curran
AU - Lee, Seungho
AU - Van Den Eynden, Dietger
AU - Ibáñez, Maria
AU - Regoutz, Anna
AU - De Roo, Jonathan
ID - 11451
IS - 31
JF - Angewandte Chemie - International Edition
SN - 1433-7851
TI - The chemistry of Cu₃N and Cu₃PdN nanocrystals
VL - 61
ER -
TY - GEN
AB - Data underlying the figures in the publication "The chemistry of Cu3N and Cu3PdN nanocrystals"
AU - Parvizian, Mahsa
AU - Duran Balsa, Alejandra
AU - Pokratath, Rohan
AU - Kalha, Curran
AU - Lee, Seungho
AU - Van den Eynden, Dietger
AU - Ibáñez, Maria
AU - Regoutz, Anna
AU - De Roo, Jonathan
ID - 11695
TI - Data for "The chemistry of Cu3N and Cu3PdN nanocrystals"
ER -
TY - JOUR
AB - The broad implementation of thermoelectricity requires high-performance and low-cost materials. One possibility is employing surfactant-free solution synthesis to produce nanopowders. We propose the strategy of functionalizing “naked” particles’ surface by inorganic molecules to control the nanostructure and, consequently, thermoelectric performance. In particular, we use bismuth thiolates to functionalize surfactant-free SnTe particles’ surfaces. Upon thermal processing, bismuth thiolates decomposition renders SnTe-Bi2S3 nanocomposites with synergistic functions: 1) carrier concentration optimization by Bi doping; 2) Seebeck coefficient enhancement and bipolar effect suppression by energy filtering; and 3) lattice thermal conductivity reduction by small grain domains, grain boundaries and nanostructuration. Overall, the SnTe-Bi2S3 nanocomposites exhibit peak z T up to 1.3 at 873 K and an average z T of ≈0.6 at 300–873 K, which is among the highest reported for solution-processed SnTe.
AU - Chang, Cheng
AU - Liu, Yu
AU - Lee, Seungho
AU - Spadaro, Maria
AU - Koskela, Kristopher M.
AU - Kleinhanns, Tobias
AU - Costanzo, Tommaso
AU - Arbiol, Jordi
AU - Brutchey, Richard L.
AU - Ibáñez, Maria
ID - 11705
IS - 35
JF - Angewandte Chemie - International Edition
SN - 1433-7851
TI - Surface functionalization of surfactant-free particles: A strategy to tailor the properties of nanocomposites for enhanced thermoelectric performance
VL - 61
ER -
TY - JOUR
AB - Thermoelectric technology requires synthesizing complex materials where not only the crystal structure but also other structural features such as defects, grain size and orientation, and interfaces must be controlled. To date, conventional solid-state techniques are unable to provide this level of control. Herein, we present a synthetic approach in which dense inorganic thermoelectric materials are produced by the consolidation of well-defined nanoparticle powders. The idea is that controlling the characteristics of the powder allows the chemical transformations that take place during consolidation to be guided, ultimately yielding inorganic solids with targeted features. Different from conventional methods, syntheses in solution can produce particles with unprecedented control over their size, shape, crystal structure, composition, and surface chemistry. However, to date, most works have focused only on the low-cost benefits of this strategy. In this perspective, we first cover the opportunities that solution processing of the powder offers, emphasizing the potential structural features that can be controlled by precisely engineering the inorganic core of the particle, the surface, and the organization of the particles before consolidation. We then discuss the challenges of this synthetic approach and more practical matters related to solution processing. Finally, we suggest some good practices for adequate knowledge transfer and improving reproducibility among different laboratories.
AU - Fiedler, Christine
AU - Kleinhanns, Tobias
AU - Garcia, Maria
AU - Lee, Seungho
AU - Calcabrini, Mariano
AU - Ibáñez, Maria
ID - 12237
IS - 19
JF - Chemistry of Materials
KW - Materials Chemistry
KW - General Chemical Engineering
KW - General Chemistry
SN - 0897-4756
TI - Solution-processed inorganic thermoelectric materials: Opportunities and challenges
VL - 34
ER -
TY - JOUR
AB - A versatile, scalable, room temperature and surfactant-free route for the synthesis of metal chalcogenide nanoparticles in aqueous solution is detailed here for the production of PbS and Cu-doped PbS nanoparticles. Subsequently, nanoparticles are annealed in a reducing atmosphere to remove surface oxide, and consolidated into dense polycrystalline materials by means of spark plasma sintering. By characterizing the transport properties of the sintered material, we observe the annealing step and the incorporation of Cu to play a key role in promoting the thermoelectric performance of PbS. The presence of Cu allows improving the electrical conductivity by increasing the charge carrier concentration and simultaneously maintaining a large charge carrier mobility, which overall translates into record power factors at ambient temperature, 2.3 mWm-1K−2. Simultaneously, the lattice thermal conductivity decreases with the introduction of Cu, leading to a record high ZT = 0.37 at room temperature and ZT = 1.22 at 773 K. Besides, a record average ZTave = 0.76 is demonstrated in the temperature range 320–773 K for n-type Pb0.955Cu0.045S.
AU - Li, Mengyao
AU - Liu, Yu
AU - Zhang, Yu
AU - Chang, Cheng
AU - Zhang, Ting
AU - Yang, Dawei
AU - Xiao, Ke
AU - Arbiol, Jordi
AU - Ibáñez, Maria
AU - Cabot, Andreu
ID - 10566
JF - Chemical Engineering Journal
SN - 1385-8947
TI - Room temperature aqueous-based synthesis of copper-doped lead sulfide nanoparticles for thermoelectric application
VL - 433
ER -
TY - JOUR
AB - High-entropy materials offer numerous advantages as catalysts, including a flexible composition to tune the catalytic activity and selectivity and a large variety of adsorption/reaction sites for multistep or multiple reactions. Herein, we report on the synthesis, properties, and electrocatalytic performance of an amorphous high-entropy boride based on abundant transition metals, CoFeNiMnZnB. This metal boride provides excellent performance toward the oxygen evolution reaction (OER), including a low overpotential of 261 mV at 10 mA cm–2, a reduced Tafel slope of 56.8 mV dec–1, and very high stability. The outstanding OER performance of CoFeNiMnZnB is attributed to the synergistic interactions between the different metals, the leaching of Zn ions, the generation of oxygen vacancies, and the in situ formation of an amorphous oxyhydroxide at the CoFeNiMnZnB surface during the OER.
AU - Wang, Xiang
AU - Zuo, Yong
AU - Horta, Sharona
AU - He, Ren
AU - Yang, Linlin
AU - Ostovari Moghaddam, Ahmad
AU - Ibáñez, Maria
AU - Qi, Xueqiang
AU - Cabot, Andreu
ID - 12236
IS - 42
JF - ACS Applied Materials & Interfaces
KW - General Materials Science
SN - 1944-8244
TI - CoFeNiMnZnB as a high-entropy metal boride to boost the oxygen evolution reaction
VL - 14
ER -
TY - JOUR
AB - Thermoelectric materials allow for direct conversion between heat and electricity, offering the potential for power generation. The average dimensionless figure of merit ZTave determines device efficiency. N-type tin selenide crystals exhibit outstanding three-dimensional charge and two-dimensional phonon transport along the out-of-plane direction, contributing to a high maximum figure of merit Zmax of ~3.6 × 10−3 per kelvin but a moderate ZTave of ~1.1. We found an attractive high Zmax of ~4.1 × 10−3 per kelvin at 748 kelvin and a ZTave of ~1.7 at 300 to 773 kelvin in chlorine-doped and lead-alloyed tin selenide crystals by phonon-electron decoupling. The chlorine-induced low deformation potential improved the carrier mobility. The lead-induced mass and strain fluctuations reduced the lattice thermal conductivity. Phonon-electron decoupling plays a critical role to achieve high-performance thermoelectrics.
AU - Su, Lizhong
AU - Wang, Dongyang
AU - Wang, Sining
AU - Qin, Bingchao
AU - Wang, Yuping
AU - Qin, Yongxin
AU - Jin, Yang
AU - Chang, Cheng
AU - Zhao, Li Dong
ID - 11144
IS - 6587
JF - Science
TI - High thermoelectric performance realized through manipulating layered phonon-electron decoupling
VL - 375
ER -
TY - JOUR
AB - Future LEDs could be based on lead halide perovskites. A breakthrough in preparing device-compatible solids composed of nanoscale perovskite crystals overcomes a long-standing hurdle in making blue perovskite LEDs.
AU - Utzat, Hendrik
AU - Ibáñez, Maria
ID - 14437
IS - 7941
JF - Nature
KW - Multidisciplinary
SN - 0028-0836
TI - Molecular engineering enables bright blue LEDs
VL - 612
ER -
TY - JOUR
AB - The growing demand of thermal management in various fields such as miniaturized 5G chips has motivated researchers to develop new and high-performance solid-state refrigeration technologies, typically including multicaloric and thermoelectric (TE) cooling. Among them, TE cooling has attracted huge attention owing to its advantages of rapid response, large cooling temperature difference, high stability, and tunable device size. Bi2Te3-based alloys have long been the only commercialized TE cooling materials, while novel systems SnSe and Mg3(Bi,Sb)2 have recently been discovered as potential candidates. However, challenges and problems still require to be summarized and further resolved for realizing better cooling performance. In this review, we systematically investigate TE cooling from its internal mechanism, crucial parameters, to device design and applications. Furthermore, we summarize the current optimization strategies for existing TE cooling materials, and finally provide some personal prospects especially the material-planification concept on future research on establishing better TE cooling.
AU - Qin, Yongxin
AU - Qin, Bingchao
AU - Wang, Dongyang
AU - Chang, Cheng
AU - Zhao, Li-Dong
ID - 12155
IS - 11
JF - Energy & Environmental Science
KW - Pollution
KW - Nuclear Energy and Engineering
KW - Renewable Energy
KW - Sustainability and the Environment
KW - Environmental Chemistry
SN - 1754-5692
TI - Solid-state cooling: Thermoelectrics
VL - 15
ER -
TY - JOUR
AB - Ligands are a fundamental part of nanocrystals. They control and direct nanocrystal syntheses and provide colloidal stability. Bound ligands also affect the nanocrystals’ chemical reactivity and electronic structure. Surface chemistry is thus crucial to understand nanocrystal properties and functionality. Here, we investigate the synthesis of metal oxide nanocrystals (CeO2-x, ZnO, and NiO) from metal nitrate precursors, in the presence of oleylamine ligands. Surprisingly, the nanocrystals are capped exclusively with a fatty acid instead of oleylamine. Analysis of the reaction mixtures with nuclear magnetic resonance spectroscopy revealed several reaction byproducts and intermediates that are common to the decomposition of Ce, Zn, Ni, and Zr nitrate precursors. Our evidence supports the oxidation of alkylamine and formation of a carboxylic acid, thus unraveling this counterintuitive surface chemistry.
AU - Calcabrini, Mariano
AU - Van den Eynden, Dietger
AU - Sanchez Ribot, Sergi
AU - Pokratath, Rohan
AU - Llorca, Jordi
AU - De Roo, Jonathan
AU - Ibáñez, Maria
ID - 10806
IS - 11
JF - JACS Au
KW - general medicine
SN - 2691-3704
TI - Ligand conversion in nanocrystal synthesis: The oxidation of alkylamines to fatty acids by nitrate
VL - 1
ER -
TY - JOUR
AB - Cesium lead halides have intrinsically unstable crystal lattices and easily transform within perovskite and nonperovskite structures. In this work, we explore the conversion of the perovskite CsPbBr3 into Cs4PbBr6 in the presence of PbS at 450 °C to produce doped nanocrystal-based composites with embedded Cs4PbBr6 nanoprecipitates. We show that PbBr2 is extracted from CsPbBr3 and diffuses into the PbS lattice with a consequent increase in the concentration of free charge carriers. This new doping strategy enables the adjustment of the density of charge carriers between 1019 and 1020 cm–3, and it may serve as a general strategy for doping other nanocrystal-based semiconductors.
AU - Calcabrini, Mariano
AU - Genc, Aziz
AU - Liu, Yu
AU - Kleinhanns, Tobias
AU - Lee, Seungho
AU - Dirin, Dmitry N.
AU - Akkerman, Quinten A.
AU - Kovalenko, Maksym V.
AU - Arbiol, Jordi
AU - Ibáñez, Maria
ID - 9118
IS - 2
JF - ACS Energy Letters
TI - Exploiting the lability of metal halide perovskites for doping semiconductor nanocomposites
VL - 6
ER -
TY - JOUR
AB - The precise engineering of thermoelectric materials using nanocrystals as their building blocks has proven to be an excellent strategy to increase energy conversion efficiency. Here we present a synthetic route to produce Sb-doped PbS colloidal nanoparticles. These nanoparticles are then consolidated into nanocrystalline PbS:Sb using spark plasma sintering. We demonstrate that the introduction of Sb significantly influences the size, geometry, crystal lattice and especially the carrier concentration of PbS. The increase of charge carrier concentration achieved with the introduction of Sb translates into an increase of the electrical and thermal conductivities and a decrease of the Seebeck coefficient. Overall, PbS:Sb nanomaterial were characterized by two-fold higher thermoelectric figures of merit than undoped PbS.
AU - Cadavid, Doris
AU - Wei, Kaya
AU - Liu, Yu
AU - Zhang, Yu
AU - Li, Mengyao
AU - Genç, Aziz
AU - Berestok, Taisiia
AU - Ibáñez, Maria
AU - Shavel, Alexey
AU - Nolas, George S.
AU - Cabot, Andreu
ID - 9206
IS - 4
JF - Materials
TI - Synthesis, bottom up assembly and thermoelectric properties of Sb-doped PbS nanocrystal building blocks
VL - 14
ER -
TY - JOUR
AB - SnSe, a wide-bandgap semiconductor, has attracted significant attention from the thermoelectric (TE) community due to its outstanding TE performance deriving from the ultralow thermal conductivity and advantageous electronic structures. Here, we promoted the TE performance of n-type SnSe polycrystals through bandgap engineering and vacancy compensation. We found that PbTe can significantly reduce the wide bandgap of SnSe to reduce the impurity transition energy, largely enhancing the carrier concentration. Also, PbTe-induced crystal symmetry promotion increases the carrier mobility, preserving large Seebeck coefficient. Consequently, a maximum ZT of ∼1.4 at 793 K is obtained in Br doped SnSe–13%PbTe. Furthermore, we found that extra Sn in n-type SnSe can compensate for the intrinsic Sn vacancies and form electron donor-like metallic Sn nanophases. The Sn nanophases near the grain boundary could also reduce the intergrain energy barrier which largely enhances the carrier mobility. As a result, a maximum ZT value of ∼1.7 at 793 K and an average ZT (ZTave) of ∼0.58 in 300–793 K are achieved in Br doped Sn1.08Se–13%PbTe. Our findings provide a novel strategy to promote the TE performance in wide-bandgap semiconductors.
AU - Su, Lizhong
AU - Hong, Tao
AU - Wang, Dongyang
AU - Wang, Sining
AU - Qin, Bingchao
AU - Zhang, Mengmeng
AU - Gao, Xiang
AU - Chang, Cheng
AU - Zhao, Li Dong
ID - 9626
JF - Materials Today Physics
TI - Realizing high doping efficiency and thermoelectric performance in n-type SnSe polycrystals via bandgap engineering and vacancy compensation
VL - 20
ER -
TY - JOUR
AB - In 2020, many in-person scientific events were canceled due to the COVID-19 pandemic, creating a vacuum in networking and knowledge exchange between scientists. To fill this void in scientific communication, a group of early career nanocrystal enthusiasts launched the virtual seminar series, News in Nanocrystals, in the summer of 2020. By the end of the year, the series had attracted over 850 participants from 46 countries. In this Nano Focus, we describe the process of organizing the News in Nanocrystals seminar series; discuss its growth, emphasizing what the organizers have learned in terms of diversity and accessibility; and provide an outlook for the next steps and future opportunities. This summary and analysis of experiences and learned lessons are intended to inform the broader scientific community, especially those who are looking for avenues to continue fostering discussion and scientific engagement virtually, both during the pandemic and after.
AU - Baranov, Dmitry
AU - Šverko, Tara
AU - Moot, Taylor
AU - Keller, Helena R.
AU - Klein, Megan D.
AU - Vishnu, E. K.
AU - Balazs, Daniel
AU - Shulenberger, Katherine E.
ID - 9829
IS - 7
JF - ACS Nano
SN - 19360851
TI - News in Nanocrystals seminar: Self-assembly of early career researchers toward globally accessible nanoscience
VL - 15
ER -
TY - JOUR
AB - Solution synthesis of particles emerged as an alternative to prepare thermoelectric materials with less demanding processing conditions than conventional solid-state synthetic methods. However, solution synthesis generally involves the presence of additional molecules or ions belonging to the precursors or added to enable solubility and/or regulate nucleation and growth. These molecules or ions can end up in the particles as surface adsorbates and interfere in the material properties. This work demonstrates that ionic adsorbates, in particular Na⁺ ions, are electrostatically adsorbed in SnSe particles synthesized in water and play a crucial role not only in directing the material nano/microstructure but also in determining the transport properties of the consolidated material. In dense pellets prepared by sintering SnSe particles, Na remains within the crystal lattice as dopant, in dislocations, precipitates, and forming grain boundary complexions. These results highlight the importance of considering all the possible unintentional impurities to establish proper structure-property relationships and control material properties in solution-processed thermoelectric materials.
AU - Liu, Yu
AU - Calcabrini, Mariano
AU - Yu, Yuan
AU - Genç, Aziz
AU - Chang, Cheng
AU - Costanzo, Tommaso
AU - Kleinhanns, Tobias
AU - Lee, Seungho
AU - Llorca, Jordi
AU - Cojocaru‐Mirédin, Oana
AU - Ibáñez, Maria
ID - 10123
IS - 52
JF - Advanced Materials
KW - mechanical engineering
KW - mechanics of materials
KW - general materials science
SN - 0935-9648
TI - The importance of surface adsorbates in solution‐processed thermoelectric materials: The case of SnSe
VL - 33
ER -
TY - JOUR
AB - Thermoelectric materials enable the direct conversion between heat and electricity. SnTe is a promising candidate due to its high charge transport performance. Here, we prepared SnTe nanocomposites by employing an aqueous method to synthetize SnTe nanoparticles (NP), followed by a unique surface treatment prior NP consolidation. This synthetic approach allowed optimizing the charge and phonon transport synergistically. The novelty of this strategy was the use of a soluble PbS molecular complex prepared using a thiol-amine solvent mixture that upon blending is adsorbed on the SnTe NP surface. Upon consolidation with spark plasma sintering, SnTe-PbS nanocomposite is formed. The presence of PbS complexes significantly compensates for the Sn vacancy and increases the average grain size of the nanocomposite, thus improving the carrier mobility. Moreover, lattice thermal conductivity is also reduced by the Pb and S-induced mass and strain fluctuation. As a result, an enhanced ZT of ca. 0.8 is reached at 873 K. Our finding provides a novel strategy to conduct rational surface treatment on NP-based thermoelectrics.
AU - Chang, Cheng
AU - Ibáñez, Maria
ID - 10073
IS - 18
JF - Materials
TI - Enhanced thermoelectric performance by surface engineering in SnTe-PbS nanocomposites
VL - 14
ER -
TY - JOUR
AB - For many years, fullerene derivatives have been the main n-type material of organic electronics and optoelectronics. Recently, fullerene derivatives functionalized with ethylene glycol (EG) side chains have been showing important properties such as enhanced dielectric constants, facile doping and enhanced self-assembly capabilities. Here, we have prepared field-effect transistors using a series of these fullerene derivatives equipped with EG side chains of different lengths. Transport data show the beneficial effect of increasing the EG side chain. In order to understand the material properties, full structural determination of these fullerene derivatives has been achieved by coupling the X-ray data with molecular dynamics (MD) simulations. The increase in transport properties is paired with the formation of extended layered structures, efficient molecular packing and an increase in the crystallite alignment. The layer-like structure is composed of conducting layers, containing of closely packed C60 balls approaching the inter-distance of 1 nm, that are separated by well-defined EG layers, where the EG chains are rather splayed with the chain direction almost perpendicular to the layer normal. Such a layered structure appears highly ordered and highly aligned with the C60 planes oriented parallel to the substrate in the thin film configuration. The order inside the thin film increases with the EG chain length, allowing the systems to achieve mobilities as high as 0.053 cm2 V−1 s−1. Our work elucidates the structure of these interesting semiconducting organic molecules and shows that the synergistic use of X-ray structural analysis and MD simulations is a powerful tool to identify the structure of thin organic films for optoelectronic applications.
AU - Dong, Jingjin
AU - Sami, Selim
AU - Balazs, Daniel
AU - Alessandri, Riccardo
AU - Jahani, Fatimeh
AU - Qiu, Li
AU - Marrink, Siewert J.
AU - Havenith, Remco W.A.
AU - Hummelen, Jan C.
AU - Loi, Maria A.
AU - Portale, Giuseppe
ID - 10534
IS - 45
JF - Journal of Materials Chemistry C
SN - 2050-7534
TI - Fullerene derivatives with oligoethylene-glycol side chains: An investigation on the origin of their outstanding transport properties
VL - 9
ER -
TY - JOUR
AB - Thermoelectric materials are engines that convert heat into an electrical current. Intuitively, the efficiency of this process depends on how many electrons (charge carriers) can move and how easily they do so, how much energy those moving electrons transport, and how easily the temperature gradient is maintained. In terms of material properties, an excellent thermoelectric material requires a high electrical conductivity σ, a high Seebeck coefficient S (a measure of the induced thermoelectric voltage as a function of temperature gradient), and a low thermal conductivity κ. The challenge is that these three properties are strongly interrelated in a conflicting manner (1). On page 722 of this issue, Roychowdhury et al. (2) have found a way to partially break these ties in silver antimony telluride (AgSbTe2) with the addition of cadmium (Cd) cations, which increase the ordering in this inherently disordered thermoelectric material.
AU - Liu, Yu
AU - Ibáñez, Maria
ID - 10809
IS - 6530
JF - Science
KW - multidisciplinary
SN - 0036-8075
TI - Tidying up the mess
VL - 371
ER -
TY - JOUR
AB - The cost-effective conversion of low-grade heat into electricity using thermoelectric devices requires developing alternative materials and material processing technologies able to reduce the currently high device manufacturing costs. In this direction, thermoelectric materials that do not rely on rare or toxic elements such as tellurium or lead need to be produced using high-throughput technologies not involving high temperatures and long processes. Bi2Se3 is an obvious possible Te-free alternative to Bi2Te3 for ambient temperature thermoelectric applications, but its performance is still low for practical applications, and additional efforts toward finding proper dopants are required. Here, we report a scalable method to produce Bi2Se3 nanosheets at low synthesis temperatures. We studied the influence of different dopants on the thermoelectric properties of this material. Among the elements tested, we demonstrated that Sn doping resulted in the best performance. Sn incorporation resulted in a significant improvement to the Bi2Se3 Seebeck coefficient and a reduction in the thermal conductivity in the direction of the hot-press axis, resulting in an overall 60% improvement in the thermoelectric figure of merit of Bi2Se3.
AU - Li, Mengyao
AU - Zhang, Yu
AU - Zhang, Ting
AU - Zuo, Yong
AU - Xiao, Ke
AU - Arbiol, Jordi
AU - Llorca, Jordi
AU - Liu, Yu
AU - Cabot, Andreu
ID - 10858
IS - 7
JF - Nanomaterials
KW - General Materials Science
KW - General Chemical Engineering
SN - 2079-4991
TI - Enhanced thermoelectric performance of n-type Bi2Se3 nanosheets through Sn doping
VL - 11
ER -
TY - JOUR
AB - The high processing cost, poor mechanical properties and moderate performance of Bi2Te3–based alloys used in thermoelectric devices limit the cost-effectiveness of this energy conversion technology. Towards solving these current challenges, in the present work, we detail a low temperature solution-based approach to produce Bi2Te3-Cu2-xTe nanocomposites with improved thermoelectric performance. Our approach consists in combining proper ratios of colloidal nanoparticles and to consolidate the resulting mixture into nanocomposites using a hot press. The transport properties of the nanocomposites are characterized and compared with those of pure Bi2Te3 nanomaterials obtained following the same procedure. In contrast with most previous works, the presence of Cu2-xTe nanodomains does not result in a significant reduction of the lattice thermal conductivity of the reference Bi2Te3 nanomaterial, which is already very low. However, the introduction of Cu2-xTe yields a nearly threefold increase of the power factor associated to a simultaneous increase of the Seebeck coefficient and electrical conductivity at temperatures above 400 K. Taking into account the band alignment of the two materials, we rationalize this increase by considering that Cu2-xTe nanostructures, with a relatively low electron affinity, are able to inject electrons into Bi2Te3, enhancing in this way its electrical conductivity. The simultaneous increase of the Seebeck coefficient is related to the energy filtering of charge carriers at energy barriers within Bi2Te3 domains associated with the accumulation of electrons in regions nearby a Cu2-xTe/Bi2Te3 heterojunction. Overall, with the incorporation of a proper amount of Cu2-xTe nanoparticles, we demonstrate a 250% improvement of the thermoelectric figure of merit of Bi2Te3.
AU - Zhang, Yu
AU - Xing, Congcong
AU - Liu, Yu
AU - Li, Mengyao
AU - Xiao, Ke
AU - Guardia, Pablo
AU - Lee, Seungho
AU - Han, Xu
AU - Moghaddam, Ahmad
AU - Roa, Joan J
AU - Arbiol, Jordi
AU - Ibáñez, Maria
AU - Pan, Kai
AU - Prato, Mirko
AU - Xie, Ying
AU - Cabot, Andreu
ID - 9304
IS - 8
JF - Chemical Engineering Journal
SN - 1385-8947
TI - Influence of copper telluride nanodomains on the transport properties of n-type bismuth telluride
VL - 418
ER -
TY - JOUR
AB - Copper chalcogenides are outstanding thermoelectric materials for applications in the medium-high temperature range. Among different chalcogenides, while Cu2−xSe is characterized by higher thermoelectric figures of merit, Cu2−xS provides advantages in terms of low cost and element abundance. In the present work, we investigate the effect of different dopants to enhance the Cu2−xS performance and also its thermal stability. Among the tested options, Pb-doped Cu2−xS shows the highest improvement in stability against sulfur volatilization. Additionally, Pb incorporation allows tuning charge carrier concentration, which enables a significant improvement of the power factor. We demonstrate here that the introduction of an optimal additive amount of just 0.3% results in a threefold increase of the power factor in the middle-temperature range (500–800 K) and a record dimensionless thermoelectric figure of merit above 2 at 880 K.
AU - Zhang, Yu
AU - Xing, Congcong
AU - Liu, Yu
AU - Spadaro, Maria Chiara
AU - Wang, Xiang
AU - Li, Mengyao
AU - Xiao, Ke
AU - Zhang, Ting
AU - Guardia, Pablo
AU - Lim, Khak Ho
AU - Moghaddam, Ahmad Ostovari
AU - Llorca, Jordi
AU - Arbiol, Jordi
AU - Ibáñez, Maria
AU - Cabot, Andreu
ID - 9305
IS - 7
JF - Nano Energy
SN - 2211-2855
TI - Doping-mediated stabilization of copper vacancies to promote thermoelectric properties of Cu2-xS
VL - 85
ER -
TY - JOUR
AB - Composite materials offer numerous advantages in a wide range of applications, including thermoelectrics. Here, semiconductor–metal composites are produced by just blending nanoparticles of a sulfide semiconductor obtained in aqueous solution and at room temperature with a metallic Cu powder. The obtained blend is annealed in a reducing atmosphere and afterward consolidated into dense polycrystalline pellets through spark plasma sintering (SPS). We observe that, during the annealing process, the presence of metallic copper activates a partial reduction of the PbS, resulting in the formation of PbS–Pb–CuxS composites. The presence of metallic lead during the SPS process habilitates the liquid-phase sintering of the composite. Besides, by comparing the transport properties of PbS, the PbS–Pb–CuxS composites, and PbS–CuxS composites obtained by blending PbS and CuxS nanoparticles, we demonstrate that the presence of metallic lead decisively contributes to a strong increase of the charge carrier concentration through spillover of charge carriers enabled by the low work function of lead. The increase in charge carrier concentration translates into much higher electrical conductivities and moderately lower Seebeck coefficients. These properties translate into power factors up to 2.1 mW m–1 K–2 at ambient temperature, well above those of PbS and PbS + CuxS. Additionally, the presence of multiple phases in the final composite results in a notable decrease in the lattice thermal conductivity. Overall, the introduction of metallic copper in the initial blend results in a significant improvement of the thermoelectric performance of PbS, reaching a dimensionless thermoelectric figure of merit ZT = 1.1 at 750 K, which represents about a 400% increase over bare PbS. Besides, an average ZTave = 0.72 in the temperature range 320–773 K is demonstrated.
AU - Li, Mengyao
AU - Liu, Yu
AU - Zhang, Yu
AU - Han, Xu
AU - Xiao, Ke
AU - Nabahat, Mehran
AU - Arbiol, Jordi
AU - Llorca, Jordi
AU - Ibáñez, Maria
AU - Cabot, Andreu
ID - 10327
IS - 43
JF - ACS Applied Materials and Interfaces
KW - CuxS
KW - PbS
KW - energy conversion
KW - nanocomposite
KW - nanoparticle
KW - solution synthesis
KW - thermoelectric
SN - 1944-8244
TI - PbS–Pb–CuxS composites for thermoelectric application
VL - 13
ER -
TY - JOUR
AB - Cu2–xS has become one of the most promising thermoelectric materials for application in the middle-high temperature range. Its advantages include the abundance, low cost, and safety of its elements and a high performance at relatively elevated temperatures. However, stability issues limit its operation current and temperature, thus calling for the optimization of the material performance in the middle temperature range. Here, we present a synthetic protocol for large scale production of covellite CuS nanoparticles at ambient temperature and atmosphere, and using water as a solvent. The crystal phase and stoichiometry of the particles are afterward tuned through an annealing process at a moderate temperature under inert or reducing atmosphere. While annealing under argon results in Cu1.8S nanopowder with a rhombohedral crystal phase, annealing in an atmosphere containing hydrogen leads to tetragonal Cu1.96S. High temperature X-ray diffraction analysis shows the material annealed in argon to transform to the cubic phase at ca. 400 K, while the material annealed in the presence of hydrogen undergoes two phase transitions, first to hexagonal and then to the cubic structure. The annealing atmosphere, temperature, and time allow adjustment of the density of copper vacancies and thus tuning of the charge carrier concentration and material transport properties. In this direction, the material annealed under Ar is characterized by higher electrical conductivities but lower Seebeck coefficients than the material annealed in the presence of hydrogen. By optimizing the charge carrier concentration through the annealing time, Cu2–xS with record figures of merit in the middle temperature range, up to 1.41 at 710 K, is obtained. We finally demonstrate that this strategy, based on a low-cost and scalable solution synthesis process, is also suitable for the production of high performance Cu2–xS layers using high throughput and cost-effective printing technologies.
AU - Li, Mengyao
AU - Liu, Yu
AU - Zhang, Yu
AU - Han, Xu
AU - Zhang, Ting
AU - Zuo, Yong
AU - Xie, Chenyang
AU - Xiao, Ke
AU - Arbiol, Jordi
AU - Llorca, Jordi
AU - Ibáñez, Maria
AU - Liu, Junfeng
AU - Cabot, Andreu
ID - 9235
IS - 3
JF - ACS Nano
KW - General Engineering
KW - General Physics and Astronomy
KW - General Materials Science
SN - 1936-0851
TI - Effect of the annealing atmosphere on crystal phase and thermoelectric properties of copper sulfide
VL - 15
ER -
TY - JOUR
AB - Research on two-dimensional (2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since the mechanical exfoliation of graphene in 2004. Starting from graphene, 2D materials now have become a big family with numerous members and diverse categories. The unique structural features and physicochemical properties of 2D materials make them one class of the most appealing candidates for a wide range of potential applications. In particular, we have seen some major breakthroughs made in the field of 2D materials in last five years not only in developing novel synthetic methods and exploring new structures/properties but also in identifying innovative applications and pushing forward commercialisation. In this review, we provide a critical summary on the recent progress made in the field of 2D materials with a particular focus on last five years. After a brief background introduction, we first discuss the major synthetic methods for 2D materials, including the mechanical exfoliation, liquid exfoliation, vapor phase deposition, and wet-chemical synthesis as well as phase engineering of 2D materials belonging to the field of phase engineering of nanomaterials (PEN). We then introduce the superconducting/optical/magnetic properties and chirality of 2D materials along with newly emerging magic angle 2D superlattices. Following that, the promising applications of 2D materials in electronics, optoelectronics, catalysis, energy storage, solar cells, biomedicine, sensors, environments, etc. are described sequentially. Thereafter, we present the theoretic calculations and simulations of 2D materials. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future outlooks in this rapidly developing field.
AU - Chang, Cheng
AU - Chen, Wei
AU - Chen, Ye
AU - Chen, Yonghua
AU - Chen, Yu
AU - Ding, Feng
AU - Fan, Chunhai
AU - Fan, Hong Jin
AU - Fan, Zhanxi
AU - Gong, Cheng
AU - Gong, Yongji
AU - He, Qiyuan
AU - Hong, Xun
AU - Hu, Sheng
AU - Hu, Weida
AU - Huang, Wei
AU - Huang, Yuan
AU - Ji, Wei
AU - Li, Dehui
AU - Li, Lain Jong
AU - Li, Qiang
AU - Lin, Li
AU - Ling, Chongyi
AU - Liu, Minghua
AU - Liu, Nan
AU - Liu, Zhuang
AU - Loh, Kian Ping
AU - Ma, Jianmin
AU - Miao, Feng
AU - Peng, Hailin
AU - Shao, Mingfei
AU - Song, Li
AU - Su, Shao
AU - Sun, Shuo
AU - Tan, Chaoliang
AU - Tang, Zhiyong
AU - Wang, Dingsheng
AU - Wang, Huan
AU - Wang, Jinlan
AU - Wang, Xin
AU - Wang, Xinran
AU - Wee, Andrew T.S.
AU - Wei, Zhongming
AU - Wu, Yuen
AU - Wu, Zhong Shuai
AU - Xiong, Jie
AU - Xiong, Qihua
AU - Xu, Weigao
AU - Yin, Peng
AU - Zeng, Haibo
AU - Zeng, Zhiyuan
AU - Zhai, Tianyou
AU - Zhang, Han
AU - Zhang, Hui
AU - Zhang, Qichun
AU - Zhang, Tierui
AU - Zhang, Xiang
AU - Zhao, Li Dong
AU - Zhao, Meiting
AU - Zhao, Weijie
AU - Zhao, Yunxuan
AU - Zhou, Kai Ge
AU - Zhou, Xing
AU - Zhou, Yu
AU - Zhu, Hongwei
AU - Zhang, Hua
AU - Liu, Zhongfan
ID - 14800
IS - 12
JF - Acta Physico-Chimica Sinica
SN - 1001-4861
TI - Recent progress on two-dimensional materials
VL - 37
ER -
TY - JOUR
AB - Nanomaterials produced from the bottom-up assembly of nanocrystals may incorporate ∼1020–1021 cm–3 not fully coordinated surface atoms, i.e., ∼1020–1021 cm–3 potential donor or acceptor states that can strongly affect transport properties. Therefore, to exploit the full potential of nanocrystal building blocks to produce functional nanomaterials and thin films, a proper control of their surface chemistry is required. Here, we analyze how the ligand stripping procedure influences the charge and heat transport properties of sintered PbSe nanomaterials produced from the bottom-up assembly of colloidal PbSe nanocrystals. First, we show that the removal of the native organic ligands by thermal decomposition in an inert atmosphere leaves relatively large amounts of carbon at the crystal interfaces. This carbon blocks crystal growth during consolidation and at the same time hampers charge and heat transport through the final nanomaterial. Second, we demonstrate that, by stripping ligands from the nanocrystal surface before consolidation, nanomaterials with larger crystal domains, lower porosity, and higher charge carrier concentrations are obtained, thus resulting in nanomaterials with higher electrical and thermal conductivities. In addition, the ligand displacement leaves the nanocrystal surface unprotected, facilitating oxidation and chalcogen evaporation. The influence of the ligand displacement on the nanomaterial charge transport properties is rationalized here using a two-band model based on the standard Boltzmann transport equation with the relaxation time approximation. Finally, we present an application of the produced functional nanomaterials by modeling, fabricating, and testing a simple PbSe-based thermoelectric device with a ring geometry.
AU - Cadavid, Doris
AU - Ortega, Silvia
AU - Illera, Sergio
AU - Liu, Yu
AU - Ibáñez, Maria
AU - Shavel, Alexey
AU - Zhang, Yu
AU - Li, Mengyao
AU - López, Antonio M.
AU - Noriega, Germán
AU - Durá, Oscar Juan
AU - López De La Torre, M. A.
AU - Prades, Joan Daniel
AU - Cabot, Andreu
ID - 7467
IS - 3
JF - ACS Applied Energy Materials
TI - Influence of the ligand stripping on the transport properties of nanoparticle-based PbSe nanomaterials
VL - 3
ER -
TY - JOUR
AB - Assemblies of colloidal semiconductor nanocrystals (NCs) in the form of thin solid films leverage the size-dependent quantum confinement properties and the wet chemical methods vital for the development of the emerging solution-processable electronics, photonics, and optoelectronics technologies. The ability to control the charge carrier transport in the colloidal NC assemblies is fundamental for altering their electronic and optical properties for the desired applications. Here we demonstrate a strategy to render the solids of narrow-bandgap NC assemblies exclusively electron-transporting by creating a type-II heterojunction via shelling. Electronic transport of molecularly cross-linked PbTe@PbS core@shell NC assemblies is measured using both a conventional solid gate transistor and an electric-double-layer transistor, as well as compared with those of core-only PbTe NCs. In contrast to the ambipolar characteristics demonstrated by many narrow-bandgap NCs, the core@shell NCs exhibit exclusive n-type transport, i.e., drastically suppressed contribution of holes to the overall transport. The PbS shell that forms a type-II heterojunction assists the selective carrier transport by heavy doping of electrons into the PbTe-core conduction level and simultaneously strongly localizes the holes within the NC core valence level. This strongly enhanced n-type transport makes these core@shell NCs suitable for applications where ambipolar characteristics should be actively suppressed, in particular, for thermoelectric and electron-transporting layers in photovoltaic devices.
AU - Miranti, Retno
AU - Shin, Daiki
AU - Septianto, Ricky Dwi
AU - Ibáñez, Maria
AU - Kovalenko, Maksym V.
AU - Matsushita, Nobuhiro
AU - Iwasa, Yoshihiro
AU - Bisri, Satria Zulkarnaen
ID - 7634
IS - 3
JF - ACS Nano
TI - Exclusive electron transport in Core@Shell PbTe@PbS colloidal semiconductor nanocrystal assemblies
VL - 14
ER -
TY - JOUR
AB - In the present work, we report a solution-based strategy to produce crystallographically textured SnSe bulk nanomaterials and printed layers with optimized thermoelectric performance in the direction normal to the substrate. Our strategy is based on the formulation of a molecular precursor that can be continuously decomposed to produce a SnSe powder or printed into predefined patterns. The precursor formulation and decomposition conditions are optimized to produce pure phase 2D SnSe nanoplates. The printed layer and the bulk material obtained after hot press displays a clear preferential orientation of the crystallographic domains, resulting in an ultralow thermal conductivity of 0.55 W m–1 K–1 in the direction normal to the substrate. Such textured nanomaterials present highly anisotropic properties with the best thermoelectric performance in plane, i.e., in the directions parallel to the substrate, which coincide with the crystallographic bc plane of SnSe. This is an unfortunate characteristic because thermoelectric devices are designed to create/harvest temperature gradients in the direction normal to the substrate. We further demonstrate that this limitation can be overcome with the introduction of small amounts of tellurium in the precursor. The presence of tellurium allows one to reduce the band gap and increase both the charge carrier concentration and the mobility, especially the cross plane, with a minimal decrease of the Seebeck coefficient. These effects translate into record out of plane ZT values at 800 K.
AU - Zhang, Yu
AU - Liu, Yu
AU - Xing, Congcong
AU - Zhang, Ting
AU - Li, Mengyao
AU - Pacios, Mercè
AU - Yu, Xiaoting
AU - Arbiol, Jordi
AU - Llorca, Jordi
AU - Cadavid, Doris
AU - Ibáñez, Maria
AU - Cabot, Andreu
ID - 8039
IS - 24
JF - ACS Applied Materials and Interfaces
TI - Tin selenide molecular precursor for the solution processing of thermoelectric materials and devices
VL - 12
ER -
TY - JOUR
AB - Direct ethanol fuel cells (DEFCs) show a huge potential to power future electric vehicles and portable electronics, but their deployment is currently limited by the unavailability of proper electrocatalysis for the ethanol oxidation reaction (EOR). In this work, we engineer a new electrocatalyst by incorporating phosphorous into a palladium-tin alloy and demonstrate a significant performance improvement toward EOR. We first detail a synthetic method to produce Pd2Sn:P nanocrystals that incorporate 35% of phosphorus. These nanoparticles are supported on carbon black and tested for EOR. Pd2Sn:P/C catalysts exhibit mass current densities up to 5.03 A mgPd−1, well above those of Pd2Sn/C, PdP2/C and Pd/C reference catalysts. Furthermore, a twofold lower Tafel slope and a much longer durability are revealed for the Pd2Sn:P/C catalyst compared with Pd/C. The performance improvement is rationalized with the aid of density functional theory (DFT) calculations considering different phosphorous chemical environments. Depending on its oxidation state, surface phosphorus introduces sites with low energy OH− adsorption and/or strongly influences the electronic structure of palladium and tin to facilitate the oxidation of the acetyl to acetic acid, which is considered the EOR rate limiting step. DFT calculations also points out that the durability improvement of Pd2Sn:P/C catalyst is associated to the promotion of OH adsorption that accelerates the oxidation of intermediate poisoning COads, reactivating the catalyst surface.
AU - Yu, Xiaoting
AU - Liu, Junfeng
AU - Li, Junshan
AU - Luo, Zhishan
AU - Zuo, Yong
AU - Xing, Congcong
AU - Llorca, Jordi
AU - Nasiou, Déspina
AU - Arbiol, Jordi
AU - Pan, Kai
AU - Kleinhanns, Tobias
AU - Xie, Ying
AU - Cabot, Andreu
ID - 8189
IS - 11
JF - Nano Energy
SN - 2211-2855
TI - Phosphorous incorporation in Pd2Sn alloys for electrocatalytic ethanol oxidation
VL - 77
ER -
TY - JOUR
AB - Appropriately designed nanocomposites allow improving the thermoelectric performance by several mechanisms, including phonon scattering, modulation doping and energy filtering, while additionally promoting better mechanical properties than those of crystalline materials. Here, a strategy for producing Bi2Te3–Cu2xTe nanocomposites based on the consolidation of heterostructured nanoparticles is described and the thermoelectric properties of the obtained materials are investigated. We first detail a two-step solution-based process to produce Bi2Te3–Cu2xTe heteronanostructures, based on the growth of Cu2xTe nanocrystals on the surface of Bi2Te3 nanowires. We characterize the structural and chemical properties of the synthesized nanostructures and of the nanocomposites
produced by hot-pressing the particles at moderate temperatures. Besides, the transport properties of the nanocomposites are investigated as a function of the amount of Cu introduced. Overall, the presence of Cu decreases the material thermal conductivity through promotion of phonon scattering, modulates the charge carrier concentration through electron spillover, and increases the Seebeck coefficient through filtering of charge carriers at energy barriers. These effects result in an improvement of over 50% of the thermoelectric figure of merit of Bi2Te3.
AU - Zhang, Yu
AU - Liu, Yu
AU - Calcabrini, Mariano
AU - Xing, Congcong
AU - Han, Xu
AU - Arbiol, Jordi
AU - Cadavid, Doris
AU - Ibáñez, Maria
AU - Cabot, Andreu
ID - 8747
IS - 40
JF - Journal of Materials Chemistry C
TI - Bismuth telluride-copper telluride nanocomposites from heterostructured building blocks
VL - 8
ER -
TY - JOUR
AB - Bimetallic nanoparticles with tailored size and specific composition have shown promise as stable and selective catalysts for electrochemical reduction of CO2 (CO2R) in batch systems. Yet, limited effort was devoted to understand the effect of ligand coverage and postsynthesis treatments on CO2 reduction, especially under industrially applicable conditions, such as at high currents (>100 mA/cm2) using gas diffusion electrodes (GDE) and flow reactors. In this work, Cu–Ag core–shell nanoparticles (11 ± 2 nm) were prepared with three different surface modes: (i) capped with oleylamine, (ii) capped with monoisopropylamine, and (iii) surfactant-free with a reducing borohydride agent; Cu–Ag (OAm), Cu–Ag (MIPA), and Cu–Ag (NaBH4), respectively. The ligand exchange and removal was evidenced by infrared spectroscopy (ATR-FTIR) analysis, whereas high-resolution scanning transmission electron microscopy (HAADF-STEM) showed their effect on the interparticle distance and nanoparticle rearrangement. Later on, we developed a process-on-substrate method to track these effects on CO2R. Cu–Ag (OAm) gave a lower on-set potential for hydrocarbon production, whereas Cu–Ag (MIPA) and Cu–Ag (NaBH4) promoted syngas production. The electrochemical impedance and surface area analysis on the well-controlled electrodes showed gradual increases in the electrical conductivity and active surface area after each surface treatment. We found that the increasing amount of the triple phase boundaries (the meeting point for the electron–electrolyte–CO2 reactant) affect the required electrode potential and eventually the C+2e̅/C2e̅ product ratio. This study highlights the importance of the electron transfer to those active sites affected by the capping agents—particularly on larger substrates that are crucial for their industrial application.
AU - Irtem, Erdem
AU - Arenas Esteban, Daniel
AU - Duarte, Miguel
AU - Choukroun, Daniel
AU - Lee, Seungho
AU - Ibáñez, Maria
AU - Bals, Sara
AU - Breugelmans, Tom
ID - 8926
IS - 22
JF - ACS Catalysis
TI - Ligand-mode directed selectivity in Cu-Ag core-shell based gas diffusion electrodes for CO2 electroreduction
VL - 10
ER -
TY - JOUR
AB - Research in the field of colloidal semiconductor nanocrystals (NCs) has progressed tremendously, mostly because of their exceptional optoelectronic properties. Core@shell NCs, in which one or more inorganic layers overcoat individual NCs, recently received significant attention due to their remarkable optical characteristics. Reduced Auger recombination, suppressed blinking, and enhanced carrier multiplication are among the merits of core@shell NCs. Despite their importance in device development, the influence of the shell and the surface modification of the core@shell NC assemblies on the charge carrier transport remains a pertinent research objective. Type-II PbTe@PbS core@shell NCs, in which exclusive electron transport was demonstrated, still exhibit instability of their electron
ransport. Here, we demonstrate the enhancement of electron transport and stability in PbTe@PbS core@shell NC assemblies using iodide as a surface passivating ligand. The combination of the PbS shelling and the use of the iodide ligand contributes to the addition of one mobile electron for each core@shell NC. Furthermore, both electron mobility and on/off current modulation ratio values of the core@shell NC field-effect transistor are steady with the usage of iodide. Excellent stability in these exclusively electron-transporting core@shell NCs paves the way for their utilization in electronic devices.
AU - Miranti, Retno
AU - Septianto, Ricky Dwi
AU - Ibáñez, Maria
AU - Kovalenko, Maksym V.
AU - Matsushita, Nobuhiro
AU - Iwasa, Yoshihiro
AU - Bisri, Satria Zulkarnaen
ID - 8746
IS - 17
JF - Applied Physics Letters
SN - 0003-6951
TI - Electron transport in iodide-capped core@shell PbTe@PbS colloidal nanocrystal solids
VL - 117
ER -
TY - JOUR
AB - Methodologies that involve the use of nanoparticles as “artificial atoms” to rationally build materials in a bottom-up fashion are particularly well-suited to control the matter at the nanoscale. Colloidal synthetic routes allow for an exquisite control over such “artificial atoms” in terms of size, shape, and crystal phase as well as core and surface compositions. We present here a bottom-up approach to produce Pb–Ag–K–S–Te nanocomposites, which is a highly promising system for thermoelectric energy conversion. First, we developed a high-yield and scalable colloidal synthesis route to uniform lead sulfide (PbS) nanorods, whose tips are made of silver sulfide (Ag2S). We then took advantage of the large surface-to-volume ratio to introduce a p-type dopant (K) by replacing native organic ligands with K2Te. Upon thermal consolidation, K2Te-surface modified PbS–Ag2S nanorods yield p-type doped nanocomposites with PbTe and PbS as major phases and Ag2S and Ag2Te as embedded nanoinclusions. Thermoelectric characterization of such consolidated nanosolids showed a high thermoelectric figure-of-merit of 1 at 620 K.
AU - Ibáñez, Maria
AU - Genç, Aziz
AU - Hasler, Roger
AU - Liu, Yu
AU - Dobrozhan, Oleksandr
AU - Nazarenko, Olga
AU - Mata, María de la
AU - Arbiol, Jordi
AU - Cabot, Andreu
AU - Kovalenko, Maksym V.
ID - 6566
IS - 6
JF - ACS Nano
KW - colloidal nanoparticles
KW - asymmetric nanoparticles
KW - inorganic ligands
KW - heterostructures
KW - catalyst assisted growth
KW - nanocomposites
KW - thermoelectrics
SN - 1936-0851
TI - Tuning transport properties in thermoelectric nanocomposites through inorganic ligands and heterostructured building blocks
VL - 13
ER -
TY - JOUR
AB - Indigoidine is a blue natural pigment, which can be efficiently synthetized in E. coli. In addition to its antioxidant and antimicrobial activities indigoidine due to its stability and deep blue color can find an application as an industrial, environmentally friendly dye. Moreover, similarly to its counterpart regular indigo dye, due to its molecular structure, indigoidine is an organic semiconductor. Fully conjugated aromatic moiety and intermolecular hydrogen bonding of indigoidine result in an unusually narrow bandgap for such a small molecule. This, in its turn, result is tight molecular packing in the solid state and opens a path for a wide range of application in organic and bio-electronics, such as electrochemical and field effect transistors, organic solar cells, light and bio-sensors etc.
AU - Yumusak, Cigdem
AU - Prochazkova, Anna Jancik
AU - Apaydin, Dogukan H
AU - Seelajaroen, Hathaichanok
AU - Sariciftci, Niyazi Serdar
AU - Weiter, Martin
AU - Krajcovic, Jozef
AU - Qin, Yong
AU - Zhang, Wei
AU - Zhan, Jixun
AU - Kovalenko, Alexander
ID - 6818
JF - Dyes and Pigments
SN - 0143-7208
TI - Indigoidine - Biosynthesized organic semiconductor
VL - 171
ER -
TY - JOUR
AB - The bottom-up assembly of colloidal nanocrystals is a versatile methodology to produce composite nanomaterials with precisely tuned electronic properties. Beyond the synthetic control over crystal domain size, shape, crystal phase, and composition, solution-processed nanocrystals allow exquisite surface engineering. This provides additional means to modulate the nanomaterial characteristics and particularly its electronic transport properties. For instance, inorganic surface ligands can be used to tune the type and concentration of majority carriers or to modify the electronic band structure. Herein, we report the thermoelectric properties of SnTe nanocomposites obtained from the consolidation of surface-engineered SnTe nanocrystals into macroscopic pellets. A CdSe-based ligand is selected to (i) converge the light and heavy bands through partial Cd alloying and (ii) generate CdSe nanoinclusions as a secondary phase within the SnTe matrix, thereby reducing the thermal conductivity. These SnTe-CdSe nanocomposites possess thermoelectric figures of merit of up to 1.3 at 850 K, which is, to the best of our knowledge, the highest thermoelectric figure of merit reported for solution-processed SnTe.
AU - Ibáñez, Maria
AU - Hasler, Roger
AU - Genç, Aziz
AU - Liu, Yu
AU - Kuster, Beatrice
AU - Schuster, Maximilian
AU - Dobrozhan, Oleksandr
AU - Cadavid, Doris
AU - Arbiol, Jordi
AU - Cabot, Andreu
AU - Kovalenko, Maksym V.
ID - 6586
IS - 20
JF - Journal of the American Chemical Society
SN - 0002-7863
TI - Ligand-mediated band engineering in bottom-up assembled SnTe nanocomposites for thermoelectric energy conversion
VL - 141
ER -
TY - JOUR
AB - In the present work, we detail a fast and simple solution-based method to synthesize hexagonal SnSe2 nanoplates (NPLs) and their use to produce crystallographically textured SnSe2 nanomaterials. We also demonstrate that the same strategy can be used to produce orthorhombic SnSe nanostructures and nanomaterials. NPLs are grown through a screw dislocation-driven mechanism. This mechanism typically results in pyramidal structures, but we demonstrate here that the growth from multiple dislocations results in flower-like structures. Crystallographically textured SnSe2 bulk nanomaterials obtained from the hot pressing of these SnSe2 structures display highly anisotropic charge and heat transport properties and thermoelectric (TE) figures of merit limited by relatively low electrical conductivities. To improve this parameter, SnSe2 NPLs are blended here with metal nanoparticles. The electrical conductivities of the blends are significantly improved with respect to bare SnSe2 NPLs, what translates into a three-fold increase of the TE Figure of merit, reaching unprecedented ZT values up to 0.65.
AU - Zhang, Yu
AU - Liu, Yu
AU - Lim, Khak Ho
AU - Xing, Congcong
AU - Li, Mengyao
AU - Zhang, Ting
AU - Tang, Pengyi
AU - Arbiol, Jordi
AU - Llorca, Jordi
AU - Ng, Ka Ming
AU - Ibáñez, Maria
AU - Guardia, Pablo
AU - Prato, Mirko
AU - Cadavid, Doris
AU - Cabot, Andreu
ID - 5982
IS - 52
JF - Angewandte Chemie International Edition
SN - 1433-7851
TI - Tin diselenide molecular precursor for solution-processable thermoelectric materials
VL - 57
ER -