@article{22967, abstract = {Alkali salts are widely used in solution processing, yet the corresponding cations are often assumed to remain in the liquid phase. Here, we show that alkali ions introduced during the solution synthesis of SnSe are retained through particle isolation and continue to influence the material during subsequent thermal processing, where they shape the evolution of the final polycrystalline material. Different SnSe powders were prepared using Li+, Na+, and K+ precursors, as well as tetramethylammonium (TMA+) precursors as a nonalkali reference for comparison, and all samples were consolidated under identical conditions. Although all three alkali ions were found in the matrix, at grain boundaries, and in segregated nanoscale regions, they partitioned differently and resulted in distinct grain sizes, defect distributions, and therefore transport properties. Li induced the strongest grain size heterogeneity and the lowest energy barriers, Na the best overall balance between carrier concentration and mobility, and K the broadest alkali-rich grain boundary regions along with the strongest interfacial penalty to charge carrier transport. These results show that residual alkali ions are not just remnants of solution synthesis but active determinants of microstructure and thermoelectric performance in SnSe.}, author = {Fiedler, Christine and Horta, Sharona and Navita, Navita and Maji, Krishnendu and Kleinhanns, Tobias and Llorca, Jordi and Wang, Qi and Ramon, Maria Garcia and Das, Sambit and Gavini, Vikram and Liu, Yu and Ibáñez, Maria}, issn = {1520-5002}, journal = {Chemistry of Materials}, number = {18}, pages = {9323–9332}, publisher = {American Chemical Society}, title = {{Alkali ions retained from synthesis govern microstructure and transport in solution-processed SnSe}}, doi = {10.1021/acs.chemmater.6c01284}, volume = {38}, year = {2026}, } @article{19847, abstract = {Prussian blue (PB) and Prussian blue analogues (PBAs) are a class of porous materials composed of transition metal cations, cyanide ligands, and alkali metal cations. Their ability to intercalate and deintercalate ions within their framework pores, coupled with the adaptability of their crystal structure to electrochemical changes, underpins their success in battery applications. PBAs with Fe or Co as the active site exhibit high redox potentials (vs SHE) and have been extensively explored as cathode materials, with well-documented chemistry, crystal structures, and electrochemical properties. In contrast, PBAs with Cr or Mn as the active site display lower redox potentials and remain significantly underexplored as anode materials. This gap has led to fewer reported compounds and a less comprehensive understanding of their structural and electrochemical behavior, leaving the field relatively opaque. In this perspective, we comprehensively analyze the challenges involved in producing and employing PBAs with low redox potentials as active battery materials. Conversely, we propose numerous horizons and ask fundamental questions that should pave the way for future research to advance the field.}, author = {Palacios Corella, Mario and Echevarría, Igor and Santana Santos, Carla and Schuhmann, Wolfgang and Ventosa, Edgar and Ibáñez, Maria}, issn = {1520-5002}, journal = {Chemistry of Materials}, number = {12}, pages = {4203--4226}, publisher = {American Chemical Society}, title = {{Prussian blue analogues as anode materials for battery applications: Complexities and horizons}}, doi = {10.1021/acs.chemmater.5c00213}, volume = {37}, year = {2025}, } @article{12331, abstract = {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.}, author = {Wang, Siqi and Chang, Cheng and Bai, Shulin and Qin, Bingchao and Zhu, Yingcai and Zhan, Shaoping and Zheng, Junqing and Tang, Shuwei and Zhao, Li Dong}, issn = {1520-5002}, journal = {Chemistry of Materials}, number = {2}, pages = {755--763}, publisher = {American Chemical Society}, title = {{Fine tuning of defects enables high carrier mobility and enhanced thermoelectric performance of n-type PbTe}}, doi = {10.1021/acs.chemmater.2c03542}, volume = {35}, year = {2023}, } @article{12237, abstract = {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.}, author = {Fiedler, Christine and Kleinhanns, Tobias and Garcia, Maria and Lee, Seungho and Calcabrini, Mariano and Ibáñez, Maria}, issn = {1520-5002}, journal = {Chemistry of Materials}, keywords = {Materials Chemistry, General Chemical Engineering, General Chemistry}, number = {19}, pages = {8471--8489}, publisher = {American Chemical Society}, title = {{Solution-processed inorganic thermoelectric materials: Opportunities and challenges ∇}}, doi = {10.1021/acs.chemmater.2c01967}, volume = {34}, year = {2022}, } @article{15260, abstract = {Significant advances in the synthesis and processing of colloidal nanocrystals have given scientists and engineers access to a vast library of building blocks with precisely defined size, shape, and composition. These materials have inspired exciting prospects to enable bottom-up fabrication of programmable materials with properties by design. Successfully assembling and connecting the building blocks into superstructures in which constituent nanocrystals can purposefully interact requires robust understanding of and control over a complex interplay of dynamic physicochemical processes. Fluid interfaces provide an advantageous experimental workbench to both probe and control these processes. Despite the ostensible simplicity of fabricating nanocrystal assemblies at a fluid interface, sensitivity to processing conditions and limited reproducibility have underscored the complexity of this process. In situ studies have provided mechanistic insights into the competing dynamics of key subprocesses including solvent spreading and evaporation, superlattice formation, ligand detachment kinetics, and nanocrystal attachment. Understanding how these subprocesses influence the complex choreography of self-assembly, structure transformation, and oriented attachment processes presents a rich research challenge. In this context, we present a detailed methodology for self-assembly and attachment of lead chalcogenide nanocrystals at a liquid–gas interface as a model system for the fabrication of mono- and multilayer cubic connected superlattices. We discuss key experimental parameters such as the characteristics of the building blocks and processing conditions and detailed steps from colloidal nanocrystal injection to superlattice transfer. We hope that this Methods/Protocols paper will provide guidance for future advances in the exciting path toward bringing the prospect of nanocrystal-based programmable materials to fruition.}, author = {Cimada daSilva, Jessica and Balazs, Daniel and Dunbar, Tyler A. and Hanrath, Tobias}, issn = {1520-5002}, journal = {Chemistry of Materials}, keywords = {Materials Chemistry, General Chemical Engineering, General Chemistry}, number = {24}, pages = {9457--9472}, publisher = {American Chemical Society}, title = {{Fundamental processes and practical considerations of lead chalcogenide mesocrystals formed via self-assembly and directed attachment of nanocrystals at a fluid interface}}, doi = {10.1021/acs.chemmater.1c02910}, volume = {33}, year = {2021}, } @article{15107, author = {Roy, Soumendu and Roy, Sumit and Rao, Anish and Devatha, Gayathri and Pillai, Pramod P.}, issn = {1520-5002}, journal = {Chemistry of Materials}, keywords = {Materials Chemistry, General Chemical Engineering, General Chemistry}, number = {23}, pages = {8415--8419}, publisher = {American Chemical Society}, title = {{Precise nanoparticle–reactant interaction outplays ligand poisoning in visible-light photocatalysis}}, doi = {10.1021/acs.chemmater.8b03108}, volume = {30}, year = {2018}, } @article{7286, abstract = {The solid electrolyte interphase (SEI) in Li and Na ion batteries forms when highly reducing or oxidizing electrode materials come into contact with a liquid organic electrolyte. Its ability to form a mechanically robust, ion-conducting, and electron-insulating layer critically determines performance, cycle life, and safety. Li or Na alkyl carbonates (LiAC and NaAC, respectively) are lead SEI components in state-of-the-art carbonate based electrolytes, and our fundamental understanding of their charge transport and mechanical properties may hold the key to designing electrolytes forming an improved SEI. We synthesized a homologous series of LiACs and NaACs from methyl to octyl analogues and characterized them with respect to structure, ionic conductivity, and stiffness. The compounds assume layered structures except for the lithium methyl carbonate. Room-temperature conductivities were found to be ∼10–9 S cm–1 for lithium methyl carbonate, <10–12 S cm–1 for the other LiACs, and <10–12 S cm–1 for the NaACs with ion transport mostly attributed to grain boundaries. While LiACs show stiffnesses of ∼1 GPa, NaACs become significantly softer with increasing chain lengths. These findings will help to more precisely interpret the complex results from charge transport and mechanical characterization of real SEIs and can give a rationale for influencing the SEI’s mechanical properties via the electrolyte.}, author = {Schafzahl, Lukas and Ehmann, Heike and Kriechbaum, Manfred and Sattelkow, Jürgen and Ganner, Thomas and Plank, Harald and Wilkening, Martin and Freunberger, Stefan Alexander}, issn = {1520-5002}, journal = {Chemistry of Materials}, number = {10}, pages = {3338--3345}, publisher = {ACS}, title = {{Long-chain Li and Na alkyl carbonates as solid electrolyte interphase components: Structure, ion transport, and mechanical properties}}, doi = {10.1021/acs.chemmater.8b00750}, volume = {30}, year = {2018}, } @article{375, abstract = {Branched nanocrystals (NCs) enable high atomic surface exposure within a crystalline network that provides avenues for charge transport. This combination of properties makes branched NCs particularly suitable for a range of applications where both interaction with the media and charge transport are involved. Herein we report on the colloidal synthesis of branched ceria NCs by means of a ligand-mediated overgrowth mechanism. In particular, the differential coverage of oleic acid as an X-type ligand at ceria facets with different atomic density, atomic coordination deficiency, and oxygen vacancy density resulted in a preferential growth in the [111] direction and thus in the formation of ceria octapods. Alcohols, through an esterification alcoholysis reaction, promoted faster growth rates that translated into nanostructures with higher geometrical complexity, increasing the branch aspect ratio and triggering the formation of side branches. On the other hand, the presence of water resulted in a significant reduction of the growth rate, decreasing the reaction yield and eliminating side branching, which we associate to a blocking of the surface reaction sites or a displacement of the alcoholysis reaction. Overall, adjusting the amounts of each chemical, well-defined branched ceria NCs with tuned number, thickness, and length of branches and with overall size ranging from 5 to 45 nm could be produced. We further demonstrate that such branched ceria NCs are able to provide higher surface areas and related oxygen storage capacities (OSC) than quasi-spherical NCs. }, author = {Berestok, Taisiia and Guardia, Pablo and Blanco, Javier and Nafria, Raquel and Torruella, Pau and López Conesa, Luis and Estradé, Sònia and Ibanez Sabate, Maria and De Roo, Jonathan and Luo, Zhishan and Cadavid, Doris and Martins, José and Kovalenko, Maksym and Peiró, Francesca and Cabot, Andreu}, issn = {1520-5002}, journal = {Chemistry of Materials}, number = {10}, pages = {4418 -- 4424}, publisher = {American Chemical Society}, title = {{Tuning branching in ceria nanocrystals}}, doi = {10.1021/acs.chemmater.7b00896}, volume = {29}, year = {2017}, } @article{372, abstract = {The optimization of a material functionality requires both the rational design and precise engineering of its structural and chemical parameters. In this work, we show how colloidal chemistry is an excellent synthetic choice for the synthesis of novel ternary nanostructured chalcogenides, containing exclusively noble metals, with tailored morphology and composition and with potential application in the energy conversion field. Specifically, the Ag-Au-Se system has been explored from a synthetic point of view, which leads to a set of Ag2Se-based hybrid and ternary nanoparticles including the room temperature synthesis of the rare ternary Ag3AuSe2 fischesserite phase. An in-depth structural and chemical characterization of all nanomaterials has been performed, which proofed especially useful for unravelling the reaction mechanism behind the formation of the ternary phase in solution. The work is complemented with the thermal and electric characterization of a ternary Ag-Au-Se nanocomposite with promising results: we found that the use of the ternary nanocomposite represents a clear improvement in terms of thermoelectric energy conversion as compared to a binary Ag-Se nanocomposite analogue. }, author = {Dalmases, Mariona and Ibanez Sabate, Maria and Torruella, Paul and Fernàndez Altable, Victor and López Conesa, Luis and Cadavid, Doris and Piveteau, Laura and Nachtegaal, Maarten and Llorca, Jordi and Ruiz González, Maria and Estradé, Sònia and Peiró, Francesca and Kovalenko, Maksym and Cabot, Andreu and Figuerola, Albert}, issn = {1520-5002}, journal = {Chemistry of Materials}, number = {19}, pages = {7017 -- 7028}, publisher = {American Chemical Society}, title = {{Synthesis and thermoelectric properties of noble metal ternary chalcogenide systems of Ag Au Se in the forms of alloyed nanoparticles and colloidal nanoheterostructures}}, doi = {10.1021/acs.chemmater.6b02845}, volume = {28}, year = {2016}, } @article{379, abstract = {Monodisperse Cu2ZnSnS4 (CZTS) nanocrystals (NCs), with quasi-spherical shape, were prepared by a facile, high-yield, scalable, and high-concentration heat-up procedure. The key parameters to minimize the NC size distribution were efficient mixing and heat transfer in the reaction mixture through intensive argon bubbling and improved control of the heating ramp stability. Optimized synthetic conditions allowed the production of several grams of highly monodisperse CZTS NCs per batch, with up to 5 wt % concentration in a crude solution and a yield above 90%.}, author = {Shavel, Alexey and Ibáñez, Maria and Luo, Zhishan and De Roo, Jonathan and Carrete, Alex and Dimitrievska, Mirjana and Genç, Aziz and Meyns, Michaela and Pérez Rodríguez, Alejandro and Kovalenko, Maksym and Arbol, Jordi and Cabot, Andreu}, issn = {1520-5002}, journal = {Chemistry of Materials}, number = {3}, pages = {720 -- 726}, publisher = {American Chemical Society}, title = {{Scalable heating-up synthesis of monodisperse Cu2ZnSnS4 nanocrystals}}, doi = {10.1021/acs.chemmater.5b03417}, volume = {28}, year = {2016}, }