@inproceedings{14174, abstract = {Building sample-efficient agents that generalize out-of-distribution (OOD) in real-world settings remains a fundamental unsolved problem on the path towards achieving higher-level cognition. One particularly promising approach is to begin with low-dimensional, pretrained representations of our world, which should facilitate efficient downstream learning and generalization. By training 240 representations and over 10,000 reinforcement learning (RL) policies on a simulated robotic setup, we evaluate to what extent different properties of pretrained VAE-based representations affect the OOD generalization of downstream agents. We observe that many agents are surprisingly robust to realistic distribution shifts, including the challenging sim-to-real case. In addition, we find that the generalization performance of a simple downstream proxy task reliably predicts the generalization performance of our RL agents under a wide range of OOD settings. Such proxy tasks can thus be used to select pretrained representations that will lead to agents that generalize.}, author = {Dittadi, Andrea and Träuble, Frederik and Wüthrich, Manuel and Widmaier, Felix and Gehler, Peter and Winther, Ole and Locatello, Francesco and Bachem, Olivier and Schölkopf, Bernhard and Bauer, Stefan}, booktitle = {10th International Conference on Learning Representations}, location = {Virtual}, title = {{The role of pretrained representations for the OOD generalization of reinforcement learning agents}}, year = {2022}, } @inproceedings{14175, abstract = {Predicting the future trajectory of a moving agent can be easy when the past trajectory continues smoothly but is challenging when complex interactions with other agents are involved. Recent deep learning approaches for trajectory prediction show promising performance and partially attribute this to successful reasoning about agent-agent interactions. However, it remains unclear which features such black-box models actually learn to use for making predictions. This paper proposes a procedure that quantifies the contributions of different cues to model performance based on a variant of Shapley values. Applying this procedure to state-of-the-art trajectory prediction methods on standard benchmark datasets shows that they are, in fact, unable to reason about interactions. Instead, the past trajectory of the target is the only feature used for predicting its future. For a task with richer social interaction patterns, on the other hand, the tested models do pick up such interactions to a certain extent, as quantified by our feature attribution method. We discuss the limits of the proposed method and its links to causality.}, author = {Makansi, Osama and Kügelgen, Julius von and Locatello, Francesco and Gehler, Peter and Janzing, Dominik and Brox, Thomas and Schölkopf, Bernhard}, booktitle = {10th International Conference on Learning Representations}, location = {Virtual}, title = {{You mostly walk alone: Analyzing feature attribution in trajectory prediction}}, year = {2022}, } @inproceedings{14215, abstract = {Geospatial Information Systems are used by researchers and Humanitarian Assistance and Disaster Response (HADR) practitioners to support a wide variety of important applications. However, collaboration between these actors is difficult due to the heterogeneous nature of geospatial data modalities (e.g., multi-spectral images of various resolutions, timeseries, weather data) and diversity of tasks (e.g., regression of human activity indicators or detecting forest fires). In this work, we present a roadmap towards the construction of a general-purpose neural architecture (GPNA) with a geospatial inductive bias, pre-trained on large amounts of unlabelled earth observation data in a self-supervised manner. We envision how such a model may facilitate cooperation between members of the community. We show preliminary results on the first step of the roadmap, where we instantiate an architecture that can process a wide variety of geospatial data modalities and demonstrate that it can achieve competitive performance with domain-specific architectures on tasks relating to the U.N.'s Sustainable Development Goals.}, author = {Rahaman, Nasim and Weiss, Martin and Träuble, Frederik and Locatello, Francesco and Lacoste, Alexandre and Bengio, Yoshua and Pal, Chris and Li, Li Erran and Schölkopf, Bernhard}, booktitle = {36th Conference on Neural Information Processing Systems}, location = {New Orleans, LA, United States}, title = {{A general purpose neural architecture for geospatial systems}}, year = {2022}, } @unpublished{14220, abstract = {Although reinforcement learning has seen remarkable progress over the last years, solving robust dexterous object-manipulation tasks in multi-object settings remains a challenge. In this paper, we focus on models that can learn manipulation tasks in fixed multi-object settings and extrapolate this skill zero-shot without any drop in performance when the number of objects changes. We consider the generic task of bringing a specific cube out of a set to a goal position. We find that previous approaches, which primarily leverage attention and graph neural network-based architectures, do not generalize their skills when the number of input objects changes while scaling as K2. We propose an alternative plug-and-play module based on relational inductive biases to overcome these limitations. Besides exceeding performances in their training environment, we show that our approach, which scales linearly in K, allows agents to extrapolate and generalize zero-shot to any new object number.}, author = {Mambelli, Davide and Träuble, Frederik and Bauer, Stefan and Schölkopf, Bernhard and Locatello, Francesco}, booktitle = {arXiv}, title = {{Compositional multi-object reinforcement learning with linear relation networks}}, doi = {10.48550/arXiv.2201.13388}, year = {2022}, } @unpublished{14236, abstract = {We show an $(1+\epsilon)$-approximation algorithm for maintaining maximum $s$-$t$ flow under $m$ edge insertions in $m^{1/2+o(1)} \epsilon^{-1/2}$ amortized update time for directed, unweighted graphs. This constitutes the first sublinear dynamic maximum flow algorithm in general sparse graphs with arbitrarily good approximation guarantee.}, author = {Goranci, Gramoz and Henzinger, Monika H}, booktitle = {arXiv}, title = {{Incremental approximate maximum flow in m1/2+o(1) update time}}, doi = {10.48550/arXiv.2211.09606}, year = {2022}, } @article{14248, abstract = {Recent work by Forsgård indicates that not every convex lattice polygon arises as the characteristic polygon of an affine dimer or, equivalently, an admissible oriented line arrangement on the torus in general position. We begin the classication of convex lattice polygons arising as characteristic polygons of affine dimers. We present several general constructions of new affine dimers from old, and an algorithm for finding affine dimers with prescribed polygon. With these tools we prove that all lattice triangles, generalised parallelograms, and polygons of genus at most two admit an affine dimer.}, author = {Holmes, Daniel}, issn = {2576-3725}, journal = {PUMP Journal of Undergraduate Research}, keywords = {dimer model, hyperplane arrangement, torus, lattice polygon}, pages = {24--51}, publisher = {California State University}, title = {{Affine dimers from characteristic polygons}}, volume = {5}, year = {2022}, } @article{14282, abstract = {Asymmetric multiprotein complexes that undergo subunit exchange play central roles in biology but present a challenge for design because the components must not only contain interfaces that enable reversible association but also be stable and well behaved in isolation. We use implicit negative design to generate β sheet–mediated heterodimers that can be assembled into a wide variety of complexes. The designs are stable, folded, and soluble in isolation and rapidly assemble upon mixing, and crystal structures are close to the computational models. We construct linearly arranged hetero-oligomers with up to six different components, branched hetero-oligomers, closed C4-symmetric two-component rings, and hetero-oligomers assembled on a cyclic homo-oligomeric central hub and demonstrate that such complexes can readily reconfigure through subunit exchange. Our approach provides a general route to designing asymmetric reconfigurable protein systems.}, author = {Sahtoe, Danny D. and Praetorius, Florian M and Courbet, Alexis and Hsia, Yang and Wicky, Basile I. M. and Edman, Natasha I. and Miller, Lauren M. and Timmermans, Bart J. R. and Decarreau, Justin and Morris, Hana M. and Kang, Alex and Bera, Asim K. and Baker, David}, issn = {1095-9203}, journal = {Science}, number = {6578}, publisher = {American Association for the Advancement of Science}, title = {{Reconfigurable asymmetric protein assemblies through implicit negative design}}, doi = {10.1126/science.abj7662}, volume = {375}, year = {2022}, } @article{14355, abstract = {Purpose: The mediator (MED) multisubunit-complex modulates the activity of the transcriptional machinery, and genetic defects in different MED subunits (17, 20, 27) have been implicated in neurologic diseases. In this study, we identified a recurrent homozygous variant in MED11 (c.325C>T; p.Arg109Ter) in 7 affected individuals from 5 unrelated families. Methods: To investigate the genetic cause of the disease, exome or genome sequencing were performed in 5 unrelated families identified via different research networks and Matchmaker Exchange. Deep clinical and brain imaging evaluations were performed by clinical pediatric neurologists and neuroradiologists. The functional effect of the candidate variant on both MED11 RNA and protein was assessed using reverse transcriptase polymerase chain reaction and western blotting using fibroblast cell lines derived from 1 affected individual and controls and through computational approaches. Knockouts in zebrafish were generated using clustered regularly interspaced short palindromic repeats/Cas9. Results: The disease was characterized by microcephaly, profound neurodevelopmental impairment, exaggerated startle response, myoclonic seizures, progressive widespread neurodegeneration, and premature death. Functional studies on patient-derived fibroblasts did not show a loss of protein function but rather disruption of the C-terminal of MED11, likely impairing binding to other MED subunits. A zebrafish knockout model recapitulates key clinical phenotypes. Conclusion: Loss of the C-terminal of MED subunit 11 may affect its binding efficiency to other MED subunits, thus implicating the MED-complex stability in brain development and neurodegeneration. (C) 2022 The Authors. Published by Elsevier Inc. on behalf of American College of Medical Genetics and Genomics.}, author = {Cali, Elisa and Lin, Sheng-Jia and Rocca, Clarissa and Sahin, Yavuz and Al Shamsi, Aisha and El Chehadeh, Salima and Chaabouni, Myriam and Mankad, Kshitij and Galanaki, Evangelia and Efthymiou, Stephanie and Sudhakar, Sniya and Athanasiou-Fragkouli, Alkyoni and Celik, Tamer and Narli, Nejat and Bianca, Sebastiano and Murphy, David and Moreira, Francisco Martins De Carvalho and Accogli, Andrea and Petree, Cassidy and Huang, Kevin and Monastiri, Kamel and Edizadeh, Masoud and Nardello, Rosaria and Ognibene, Marzia and De Marco, Patrizia and Ruggieri, Martino and Zara, Federico and Striano, Pasquale and Sahin, Yavuz and Al-Gazali, Lihadh and Warde, Marie Therese Abi and Gerard, Benedicte and Zifarelli, Giovanni and Beetz, Christian and Fortuna, Sara and Soler, Miguel and Valente, Enza Maria and Varshney, Gaurav and Maroofian, Reza and Salpietro, Vincenzo and Houlden, Henry and Grp, SYNaPS Study}, issn = {1098-3600}, journal = {Genetics in Medicine}, keywords = {Human mediator complex, MED11, MEDopathies}, number = {10}, pages = {2194--2203}, publisher = {Elsevier}, title = {{A homozygous MED11 C-terminal variant causes a lethal neurodegenerative disease}}, doi = {10.1016/j.gim.2022.07.013}, volume = {24}, year = {2022}, } @article{14356, abstract = {Aminoacyl-tRNA synthetases (ARSs) are essential enzymes for faithful assignment of amino acids to their cognate tRNA. Variants in ARS genes are frequently associated with clinically heterogeneous phenotypes in humans and follow both autosomal dominant or recessive inheritance patterns in many instances. Variants in tryptophanyl-tRNA synthetase 1 (WARS1) cause autosomal dominantly inherited distal hereditary motor neuropathy and Charcot-Marie-Tooth disease. Presently, only one family with biallelic WARS1 variants has been described. We present three affected individuals from two families with biallelic variants (p.Met1? and p.(Asp419Asn)) in WARS1, showing varying severities of developmental delay and intellectual disability. Hearing impairment and microcephaly, as well as abnormalities of the brain, skeletal system, movement/gait, and behavior were variable features. Phenotyping of knocked down wars-1 in a Caenorhabditis elegans model showed depletion is associated with defects in germ cell development. A wars1 knockout vertebrate model recapitulates the human clinical phenotypes, confirms variant pathogenicity, and uncovers evidence implicating the p.Met1? variant as potentially impacting an exon critical for normal hearing. Together, our findings provide consolidating evidence for biallelic disruption of WARS1 as causal for an autosomal recessive neurodevelopmental syndrome and present a vertebrate model that recapitulates key phenotypes observed in patients.}, author = {Lin, Sheng-Jia and Vona, Barbara and Porter, Hillary M. and Izadi, Mahmoud and Huang, Kevin and Lacassie, Yves and Rosenfeld, Jill A. and Khan, Saadullah and Petree, Cassidy and Ali, Tayyiba A. and Muhammad, Nazif and Khan, Sher A. and Muhammad, Noor and Liu, Pengfei and Haymon, Marie-Louise and Rueschendorf, Franz and Kong, Il-Keun and Schnapp, Linda and Shur, Natasha and Chorich, Lynn and Layman, Lawrence and Haaf, Thomas and Pourkarimi, Ehsan and Kim, Hyung-Goo and Varshney, Gaurav K.}, issn = {1059-7794}, journal = {Human Mutation}, keywords = {autosomal recessive, biallelic variants, C, elegans, translation initiation sites, tryptophanyl-tRNA synthetase 1 (WARS1), WHEP domain, zebrafish}, number = {10}, pages = {1472--1489}, publisher = {Wiley}, title = {{Biallelic variants in WARS1 cause a highly variable neurodevelopmental syndrome and implicate a critical exon for normal auditory function}}, doi = {10.1002/humu.24435}, volume = {43}, year = {2022}, } @article{14357, abstract = {Aminoacylation of transfer RNA (tRNA) is a key step in protein biosynthesis, carried out by highly specific aminoacyl-tRNA synthetases (ARSs). ARSs have been implicated in autosomal dominant and autosomal recessive human disorders. Autosomal dominant variants in tryptophanyl-tRNA synthetase 1 (WARS1) are known to cause distal hereditary motor neuropathy and Charcot-Marie-Tooth disease, but a recessively inherited phenotype is yet to be clearly defined. Seryl-tRNA synthetase 1 (SARS1) has rarely been implicated in an autosomal recessive developmental disorder. Here, we report five individuals with biallelic missense variants in WARS1 or SARS1, who presented with an overlapping phenotype of microcephaly, developmental delay, intellectual disability, and brain anomalies. Structural mapping showed that the SARS1 variant is located directly within the enzyme’s active site, most likely diminishing activity, while the WARS1 variant is located in the N-terminal domain. We further characterize the identified WARS1 variant by showing that it negatively impacts protein abundance and is unable to rescue the phenotype of a CRISPR/Cas9 wars1 knockout zebrafish model. In summary, we describe two overlapping autosomal recessive syndromes caused by variants in WARS1 and SARS1, present functional insights into the pathogenesis of the WARS1-related syndrome and define an emerging disease spectrum: ARS-related developmental disorders with or without microcephaly.}, author = {Boegershausen, Nina and Krawczyk, Hannah E. and Jamra, Rami A. and Lin, Sheng-Jia and Yigit, Goekhan and Huening, Irina and Polo, Anna M. and Vona, Barbara and Huang, Kevin and Schmidt, Julia and Altmueller, Janine and Luppe, Johannes and Platzer, Konrad and Doergeloh, Beate B. and Busche, Andreas and Biskup, Saskia and Mendes, I, Marisa and Smith, Desiree E. C. and Salomons, Gajja S. and Zibat, Arne and Bueltmann, Eva and Nuernberg, Peter and Spielmann, Malte and Lemke, Johannes R. and Li, Yun and Zenker, Martin and Varshney, Gaurav K. and Hillen, Hauke S. and Kratz, Christian P. and Wollnik, Bernd}, issn = {1059-7794}, journal = {Human Mutation}, keywords = {aminoacylation, aminoacyl-tRNA synthetase, ARS, CRISPR, Cas9, intellectual disability, microcephaly, SARS1, tRNA, WARS1, zebrafish}, number = {10}, pages = {1454--1471}, publisher = {Wiley}, title = {{WARS1 and SARS1: Two tRNA synthetases implicated in autosomal recessive microcephaly}}, doi = {10.1002/humu.24430}, volume = {43}, year = {2022}, } @article{14381, abstract = {Expander graphs (sparse but highly connected graphs) have, since their inception, been the source of deep links between Mathematics and Computer Science as well as applications to other areas. In recent years, a fascinating theory of high-dimensional expanders has begun to emerge, which is still in a formative stage but has nonetheless already lead to a number of striking results. Unlike for graphs, in higher dimensions there is a rich array of non-equivalent notions of expansion (coboundary expansion, cosystolic expansion, topological expansion, spectral expansion, etc.), with differents strengths and applications. In this talk, we will survey this landscape of high-dimensional expansion, with a focus on two main results. First, we will present Gromov’s Topological Overlap Theorem, which asserts that coboundary expansion (a quantitative version of vanishing mod 2 cohomology) implies topological expansion (roughly, the property that for every map from a simplicial complex to a manifold of the same dimension, the images of a positive fraction of the simplices have a point in common). Second, we will outline a construction of bounded degree 2-dimensional topological expanders, due to Kaufman, Kazhdan, and Lubotzky.}, author = {Wagner, Uli}, issn = {2102-622X}, journal = {Bulletin de la Societe Mathematique de France}, pages = {281--294}, publisher = {Societe Mathematique de France}, title = {{High-dimensional expanders (after Gromov, Kaufman, Kazhdan, Lubotzky, and others)}}, doi = {10.24033/ast.1188}, volume = {438}, year = {2022}, } @article{14437, abstract = {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.}, author = {Utzat, Hendrik and Ibáñez, Maria}, issn = {1476-4687}, journal = {Nature}, keywords = {Multidisciplinary}, number = {7941}, pages = {638--639}, publisher = {Springer Nature}, title = {{Molecular engineering enables bright blue LEDs}}, doi = {10.1038/d41586-022-04447-0}, volume = {612}, year = {2022}, } @article{17868, abstract = {Reversed conductance decay describes increasing conductance of a molecular chain series with increasing chain length. Realizing reversed conductance decay is an important step toward making long and highly conducting molecular wires. Recent work has shown that one-dimensional topological insulators (1D TIs) can exhibit reversed conductance decay due to their nontrivial edge states. The Su–Schrieffer–Heeger (SSH) model for 1D TIs relates to the electronic structure of these isolated molecules but not their electron transport properties as single-molecule junctions. Herein, we use a tight-binding approach to demonstrate that polyacetylene and other diradicaloid 1D TIs show a reversed conductance decay at the short chain limit. We explain these conductance trends by analyzing the impact of the edge states in these 1D systems on the single-molecule junction transmission. Additionally, we discuss how the self-energy from the electrode-molecule coupling and the on-site energy of the edge sites can be tuned to create longer wires with reversed conductance decays.}, author = {Li, Liang and Gunasekaran, Suman and Wei, Yujing and Nuckolls, Colin and Venkataraman, Latha}, issn = {1948-7185}, journal = {The Journal of Physical Chemistry Letters}, number = {41}, pages = {9703--9710}, publisher = {American Chemical Society}, title = {{Reversed conductance decay of 1D topological insulators by tight-binding analysis}}, doi = {10.1021/acs.jpclett.2c02812}, volume = {13}, year = {2022}, } @article{17869, abstract = {The formation of carbon–carbon bonds with transition metal reagents serves as a cornerstone of organic synthesis. Here, we show that the reactivity of an otherwise kinetically inert transition metal complex can be induced by an external electric field to affect a coupling reaction. These results highlight the importance of electric field effects in reaction chemistry and offers a new strategy to modulate organometallic reactivity.}, author = {Orchanian, Nicholas M. and Guizzo, Sophia and Steigerwald, Michael L. and Nuckolls, Colin and Venkataraman, Latha}, issn = {1364-548X}, journal = {Chemical Communications}, number = {90}, pages = {12556--12559}, publisher = {Royal Society of Chemistry}, title = {{Electric-field-induced coupling of aryl iodides with a nickel(0) complex}}, doi = {10.1039/d2cc03671a}, volume = {58}, year = {2022}, } @article{17870, abstract = {The electric fields created at solid–liquid interfaces are important in heterogeneous catalysis. Here we describe the Ullmann coupling of aryl iodides on rough gold surfaces, which we monitor in situ using the scanning tunneling microscope-based break junction (STM-BJ) and ex situ using mass spectrometry and fluorescence spectroscopy. We find that this Ullmann coupling reaction occurs only on rough gold surfaces in polar solvents, the latter of which implicates interfacial electric fields. These experimental observations are supported by density functional theory calculations that elucidate the roles of surface roughness and local electric fields on the reaction. More broadly, this touchstone study offers a facile method to access and probe in real time an increasingly prominent yet incompletely understood mode of catalysis.}, author = {Stone, Ilana B. and Starr, Rachel L. and Hoffmann, Norah and Wang, Xiao and Evans, Austin M. and Nuckolls, Colin and Lambert, Tristan H. and Steigerwald, Michael L. and Berkelbach, Timothy C. and Roy, Xavier and Venkataraman, Latha}, issn = {2041-6539}, journal = {Chemical Science}, number = {36}, pages = {10798--10805}, publisher = {Royal Society of Chemistry}, title = {{Interfacial electric fields catalyze Ullmann coupling reactions on gold surfaces}}, doi = {10.1039/d2sc03780g}, volume = {13}, year = {2022}, } @article{17871, abstract = {Single-molecule topological insulators are promising candidates as conducting wires over nanometre length scales. A key advantage is their ability to exhibit quasi-metallic transport, in contrast to conjugated molecular wires which typically exhibit a low conductance that decays as the wire length increases. Here, we study a family of oligophenylene-bridged bis(triarylamines) with tunable and stable mono- or di-radicaloid character. These wires can undergo one- and two-electron chemical oxidations to the corresponding mono-cation and di-cation, respectively. We show that the oxidized wires exhibit reversed conductance decay with increasing length, consistent with the expectation for Su–Schrieffer–Heeger-type one-dimensional topological insulators. The 2.6-nm-long di-cation reported here displays a conductance greater than 0.1G0, where G0 is the conductance quantum, a factor of 5,400 greater than the neutral form. The observed conductance–length relationship is similar between the mono-cation and di-cation series. Density functional theory calculations elucidate how the frontier orbitals and delocalization of radicals facilitate the observed non-classical quasi-metallic behaviour.}, author = {Li, Liang and Low, Jonathan Z. and Wilhelm, Jan and Liao, Guanming and Gunasekaran, Suman and Prindle, Claudia R. and Starr, Rachel L. and Golze, Dorothea and Nuckolls, Colin and Steigerwald, Michael L. and Evers, Ferdinand and Campos, Luis M. and Yin, Xiaodong and Venkataraman, Latha}, issn = {1755-4349}, journal = {Nature Chemistry}, number = {9}, pages = {1061--1067}, publisher = {Springer Nature}, title = {{Highly conducting single-molecule topological insulators based on mono- and di-radical cations}}, doi = {10.1038/s41557-022-00978-1}, volume = {14}, year = {2022}, } @article{17872, abstract = {Coherent tunneling electron transport through molecular wires has been theoretically established as a temperature-independent process. Although several experimental studies have shown counter examples, robust models to describe this temperature dependence have not been thoroughly developed. Here, we demonstrate that dynamic molecular structures lead to temperature-dependent conductance within coherent tunneling regime. Using a custom-built variable-temperature scanning tunneling microscopy break-junction instrument, we find that oligo[n]phenylenes exhibit clear temperature-dependent conductance. Our calculations reveal that thermally activated dihedral rotations allow these molecular wires to have a higher probability of being in a planar conformation. As the tunneling occurs primarily through π-orbitals, enhanced coplanarization substantially increases the time-averaged tunneling probability. These calculations are consistent with the observation that more rotational pivot points in longer molecular wires leads to larger temperature-dependence on conductance. These findings reveal that molecular conductance within coherent and off-resonant electron transport regimes can be controlled by manipulating dynamic molecular structure.}, author = {Lee, Woojung and Louie, Shayan and Evans, Austin M. and Orchanian, Nicholas M. and Stone, Ilana B. and Zhang, Boyuan and Wei, Yujing and Roy, Xavier and Nuckolls, Colin and Venkataraman, Latha}, issn = {1530-6992}, journal = {Nano Letters}, number = {12}, pages = {4919--4924}, publisher = {American Chemical Society}, title = {{Increased molecular conductance in Oligo[n]phenylene wires by thermally enhanced dihedral planarization}}, doi = {10.1021/acs.nanolett.2c01549}, volume = {22}, year = {2022}, } @article{17873, abstract = {AbstractA critical overview of the theory of the chirality‐induced spin selectivity (CISS) effect, that is, phenomena in which the chirality of molecular species imparts significant spin selectivity to various electron processes, is provided. Based on discussions in a recently held workshop, and further work published since, the status of CISS effects—in electron transmission, electron transport, and chemical reactions—is reviewed. For each, a detailed discussion of the state‐of‐the‐art in theoretical understanding is provided and remaining challenges and research opportunities are identified.}, author = {Evers, Ferdinand and Aharony, Amnon and Bar‐Gill, Nir and Entin‐Wohlman, Ora and Hedegård, Per and Hod, Oded and Jelinek, Pavel and Kamieniarz, Grzegorz and Lemeshko, Mikhail and Michaeli, Karen and Mujica, Vladimiro and Naaman, Ron and Paltiel, Yossi and Refaely‐Abramson, Sivan and Tal, Oren and Thijssen, Jos and Thoss, Michael and van Ruitenbeek, Jan M. and Venkataraman, Latha and Waldeck, David H. and Yan, Binghai and Kronik, Leeor}, issn = {0935-9648}, journal = {Advanced Materials}, number = {13}, publisher = {Wiley}, title = {{Theory of chirality induced spin selectivity: Progress and challenges}}, doi = {10.1002/adma.202106629}, volume = {34}, year = {2022}, } @article{17874, abstract = {Redox-active two-dimensional polymers (RA-2DPs) are promising lithium battery organic cathode materials due to their regular porosities and high chemical stabilities. However, weak electrical conductivities inherent to the non-conjugated molecular motifs used thus far limit device performance and the practical relevance of these materials. We herein address this problem by developing a modular approach to construct π-conjugated RA-2DPs with a new polycyclic aromatic redox-active building block PDI-DA. Efficient imine-condensation between PDI-DA and two polyfunctional amine nodes followed by quantitative alkyl chain removal produced RA-2DPs TAPPy-PDI and TAPB-PDI as conjugated, porous, polycrystalline networks. In-plane conjugation and permanent porosity endow these materials with high electrical conductivity and high ion diffusion rates. As such, both RA-2DPs function as organic cathode materials with good rate performance and excellent cycling stability. Importantly, the improved design enables higher areal mass-loadings than were previously available, which drives a practical demonstration of TAPPy-PDI as the power source for a series of LED lights. Collectively, this investigation discloses viable synthetic methodologies and design principles for the realization of high-performance organic cathode materials.}, author = {Jin, Zexin and Cheng, Qian and Evans, Austin M. and Gray, Jesse and Zhang, Ruiwen and Bao, Si Tong and Wei, Fengkai and Venkataraman, Latha and Yang, Yuan and Nuckolls, Colin}, issn = {2041-6539}, journal = {Chemical Science}, number = {12}, pages = {3533--3538}, publisher = {Royal Society of Chemistry}, title = {{π-Conjugated redox-active two-dimensional polymers as organic cathode materials}}, doi = {10.1039/d1sc07157b}, volume = {13}, year = {2022}, } @article{17875, abstract = {Nanoscale plasmonic structures have been primarily characterized through scattering studies, but electroluminescence offers an exciting alternative from a technological standpoint by removing the need for optical excitation. In sub-nanometer biased junctions, electronic tunneling can serve as the excitation source for plasmon-coupled electroluminescence, but the gap size dependence to this plasmonic enhancement has not been characterized. Here, we simultaneously probe the electroluminescence and conductance of Au tunnel junctions. We find that plasmonic enhancement increases as the gap size is reduced for junctions biased between 1.4 and 1.8 V, consistent with the behavior of charge transfer plasmons. At biases above 1.9 V, we see decreasing plasmonic enhancement with the decreasing gap, showing quenching due to tunneling in remarkable agreement with the trends observed for high energy plasmons in scattering experiments. Critically, we find that plasmonic enhancement of electroluminescence is gap size-dependent and, furthermore, is in agreement with the nature of modes excited by scattering.}, author = {Paoletta, Angela L. and Fung, E-Dean and Venkataraman, Latha}, issn = {2330-4022}, journal = {ACS Photonics}, number = {2}, pages = {688--693}, publisher = {American Chemical Society}, title = {{Gap size-dependent plasmonic enhancement in electroluminescent tunnel junctions}}, doi = {10.1021/acsphotonics.1c01757}, volume = {9}, year = {2022}, }