Pub Date : 2024-12-19DOI: 10.1021/acs.chemmater.4c02165
Duncan A. Peterson, Tyler W. Farnsworth, Adam H. Woomer, Zachary S. Fishman, Sydney H. Shapiro, Rebecca C. Radomsky, Emily A. Barron, Jonathan R. Thompson, Scott C. Warren
The synthesis of structurally precise materials that combine diverse building blocks will accelerate the development of artificial solids for electronics, energy, and medicine. Here, we utilize simulation to identify how organic molecules can self-assemble with 2D materials into periodic superlattices with alternating layers of molecules and 2D monolayers. We experimentally demonstrate the generalizability of this mechanism by applying it to 2D semiconductors and various organic molecules or polymers. The resulting superlattices have unique and well-defined lattice constants that depend on the dimensions of the organic species. We are able to design superlattices with a wide variety of molecules (photoresponsive, chelating, light-emitting moieties), suggesting that the self-assembly does not depend on any specific chemical interaction and yet can accommodate chemically diverse functional groups. We also observe that the 2D materials within the superlattices (MoS2, WSe2) remain quantum-confined, even though the superlattice retains excellent electrical conductivity. This introduction of a mechanism and its experimental realization yield a general design strategy for a large class of quantum-confined, molecule–2D hybrid materials.
{"title":"Generalized Assembly of Semiconductor–Molecule Superlattices","authors":"Duncan A. Peterson, Tyler W. Farnsworth, Adam H. Woomer, Zachary S. Fishman, Sydney H. Shapiro, Rebecca C. Radomsky, Emily A. Barron, Jonathan R. Thompson, Scott C. Warren","doi":"10.1021/acs.chemmater.4c02165","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02165","url":null,"abstract":"The synthesis of structurally precise materials that combine diverse building blocks will accelerate the development of artificial solids for electronics, energy, and medicine. Here, we utilize simulation to identify how organic molecules can self-assemble with 2D materials into periodic superlattices with alternating layers of molecules and 2D monolayers. We experimentally demonstrate the generalizability of this mechanism by applying it to 2D semiconductors and various organic molecules or polymers. The resulting superlattices have unique and well-defined lattice constants that depend on the dimensions of the organic species. We are able to design superlattices with a wide variety of molecules (photoresponsive, chelating, light-emitting moieties), suggesting that the self-assembly does not depend on any specific chemical interaction and yet can accommodate chemically diverse functional groups. We also observe that the 2D materials within the superlattices (MoS<sub>2</sub>, WSe<sub>2</sub>) remain quantum-confined, even though the superlattice retains excellent electrical conductivity. This introduction of a mechanism and its experimental realization yield a general design strategy for a large class of quantum-confined, molecule–2D hybrid materials.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"23 7 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142849742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-18DOI: 10.1021/acs.chemmater.4c02245
Joesene Soto, Qihao Li, Zixiao Shi, Andrés Molina Villarino, David Muller, Héctor D. Abruña
Catalysis has been crucial in advancing and commercializing energy conversion technologies. It is essential to identify abundant, active, and stable materials to enable the reliable and cost-efficient use of catalysts in renewable technologies, such as fuel cells (FCs) and electrolyzers. Suitable candidates, such as nonprecious metals, can be found in first-row transition metals, where materials such as bimetallics, metal oxides, and metal nitrides can be readily synthesized. Recently, these materials have exhibited high activity toward the oxygen reduction (ORR) and oxygen evolution (OER) reactions in alkaline media, which, in turn, were related to promising performance in FCs and electrolyzers. However, most of these studies have not gone beyond half-cell reactions. In this study, we explored the synthesis of a metal nitride, Ni3FeN, and its application as an electrocatalyst for ORR and OER. We developed procedures for the synthesis of Ni3FeN nanocrystals with different carbon loadings using a one-step ammonolysis route. We show that the pristine structure of the material encompasses a nitride core and an oxide shell with a thickness of a few nanometers. However, the bulk electronic structure is mainly dominated by the Ni3FeN phase. The nitride exhibited an impressive and stable ORR performance in 1 M KOH favoring the 4 e– pathway. The material exhibited a slight decrease in E1/2 of 10 mV (from 0.85 to 0.84 V vs RHE) during a prolonged (100 K) accelerated stress test (AST). The AST degradation at ORR potentials indicates that the catalyst aggregates into larger nanoparticles, forming a Ni@NiFeOx structure. After tests at OER potentials, the catalyst breaks into smaller nanoparticles and mainly favors the NiFeOx structure. MEA testing of the Ni3FeN ORR catalyst in a hydrogen-fueled alkaline exchange membrane fuel cell (AEMFC) yielded a peak power density of ca. 700 mW/cm2; among the highest reported for nitride and NiFe-based materials. We believe that this work could enable the use of NiFe-based materials as viable, inexpensive alternatives for fuel cell applications.
催化对能源转换技术的发展和商业化至关重要。必须找到丰富、活跃和稳定的材料，才能在燃料电池（FC）和电解槽等可再生技术中可靠、经济地使用催化剂。在第一排过渡金属中可以找到合适的候选材料，如非贵金属，在这些金属中可以很容易地合成双金属、金属氧化物和金属氮化物等材料。最近，这些材料在碱性介质中的氧还原（ORR）和氧进化（OER）反应中表现出很高的活性，这反过来又与 FC 和电解槽中的良好性能有关。然而，这些研究大多没有超出半电池反应的范围。在本研究中，我们探讨了金属氮化物 Ni3FeN 的合成及其作为 ORR 和 OER 电催化剂的应用。我们开发了使用一步氨解路线合成不同碳负载的 Ni3FeN 纳米晶体的程序。我们的研究表明，该材料的原始结构包括氮核和厚度为几纳米的氧化物外壳。然而，主体电子结构主要由 Ni3FeN 相主导。氮化物在 1 M KOH 中表现出令人印象深刻的稳定 ORR 性能，有利于 4 e- 途径。在长时间（100 K）的加速应力测试（AST）中，该材料的 E1/2 值略微下降了 10 mV（与 RHE 相比，从 0.85 V 降至 0.84 V）。AST 在 ORR 电位下的降解表明催化剂聚集成了较大的纳米颗粒，形成了 Ni@NiFeOx 结构。在 OER 电位下进行测试后，催化剂破碎成较小的纳米颗粒，并主要倾向于 NiFeOx 结构。在以氢气为燃料的碱性交换膜燃料电池（AEMFC）中对 Ni3FeN ORR 催化剂进行了 MEA 测试，结果表明其峰值功率密度约为 700 mW/cm2，是氮化物和镍铁合金材料中最高的。我们相信，这项工作能使镍钴基材料成为燃料电池应用中可行的廉价替代品。
{"title":"Surface Modulation Insights of High-Performing Ni–Fe Nitride Fuel Cell and Electrolyzer Electrocatalysts","authors":"Joesene Soto, Qihao Li, Zixiao Shi, Andrés Molina Villarino, David Muller, Héctor D. Abruña","doi":"10.1021/acs.chemmater.4c02245","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02245","url":null,"abstract":"Catalysis has been crucial in advancing and commercializing energy conversion technologies. It is essential to identify abundant, active, and stable materials to enable the reliable and cost-efficient use of catalysts in renewable technologies, such as fuel cells (FCs) and electrolyzers. Suitable candidates, such as nonprecious metals, can be found in first-row transition metals, where materials such as bimetallics, metal oxides, and metal nitrides can be readily synthesized. Recently, these materials have exhibited high activity toward the oxygen reduction (ORR) and oxygen evolution (OER) reactions in alkaline media, which, in turn, were related to promising performance in FCs and electrolyzers. However, most of these studies have not gone beyond half-cell reactions. In this study, we explored the synthesis of a metal nitride, Ni<sub>3</sub>FeN, and its application as an electrocatalyst for ORR and OER. We developed procedures for the synthesis of Ni<sub>3</sub>FeN nanocrystals with different carbon loadings using a one-step ammonolysis route. We show that the pristine structure of the material encompasses a nitride core and an oxide shell with a thickness of a few nanometers. However, the bulk electronic structure is mainly dominated by the Ni<sub>3</sub>FeN phase. The nitride exhibited an impressive and stable ORR performance in 1 M KOH favoring the 4 e<sup>–</sup> pathway. The material exhibited a slight decrease in <i>E</i><sub>1/2</sub> of 10 mV (from 0.85 to 0.84 V vs RHE) during a prolonged (100 K) accelerated stress test (AST). The AST degradation at ORR potentials indicates that the catalyst aggregates into larger nanoparticles, forming a Ni@NiFeOx structure. After tests at OER potentials, the catalyst breaks into smaller nanoparticles and mainly favors the NiFeOx structure. MEA testing of the Ni<sub>3</sub>FeN ORR catalyst in a hydrogen-fueled alkaline exchange membrane fuel cell (AEMFC) yielded a peak power density of ca. 700 mW/cm<sup>2</sup>; among the highest reported for nitride and NiFe-based materials. We believe that this work could enable the use of NiFe-based materials as viable, inexpensive alternatives for fuel cell applications.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"94 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142849751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-18DOI: 10.1021/acs.chemmater.4c02231
Alexander Shearer, Fabian Pieck, Josiah Yarbrough, Andreas Werbrouck, Ralf Tonner-Zech, Stacey F. Bent
Area-selective atomic layer deposition (AS-ALD) shows great potential for meeting the stringent demands of the semiconductor industry for precision nanopatterning. Small molecule inhibitors (SMIs) have recently proven to be a promising, industry-compatible means of achieving AS-ALD. In this work, we compare three nitrogenous aromatic SMIs – aniline, pyrrole, and pyridine – for their ability to block Al2O3 ALD on copper with (CuOx) and without (Cu) a native oxide. We find that pyrrole and aniline perform much better as inhibitors than pyridine does. Furthermore, when redosed on copper before every ALD cycle in an ABC scheme, pyrrole and aniline provide outstanding inhibition, facilitating the selective deposition of over 11 nm of Al2O3 on an SiO2 growth surface in the presence of Cu with 99.9% selectivity. By combining both theory and experiment, we provide new understanding of the mechanisms by which selectivity is prolonged and lost. First, we show that whereas pyrrole and aniline adsorb in a planar bonding orientation, pyridine binds upright at the copper surface, and we propose that the upright molecular orientation is the origin of the ineffective inhibition of pyridine. Second, we find that the CuOx surface is inherently more reactive than the Cu surface, leading to an eventual loss of selectivity, despite the redosing of the inhibitor. Finally, we observe that redosing of aniline protects the copper surface from undesired oxidation, whereas the redosing of pyridine does not. As such, we posit that a likely benefit of redosing is preventing oxidation and thus reducing reactive site formation during ALD. Through this work, we demonstrate the capability of nitrogenous aromatics to serve as SMIs for AS-ALD, and we contribute insights regarding the role of molecular orientation on inhibition and the impact of ALD process parameters on selectivity.
{"title":"Role of Molecular Orientation: Comparison of Nitrogenous Aromatic Small Molecule Inhibitors for Area-Selective Atomic Layer Deposition","authors":"Alexander Shearer, Fabian Pieck, Josiah Yarbrough, Andreas Werbrouck, Ralf Tonner-Zech, Stacey F. Bent","doi":"10.1021/acs.chemmater.4c02231","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02231","url":null,"abstract":"Area-selective atomic layer deposition (AS-ALD) shows great potential for meeting the stringent demands of the semiconductor industry for precision nanopatterning. Small molecule inhibitors (SMIs) have recently proven to be a promising, industry-compatible means of achieving AS-ALD. In this work, we compare three nitrogenous aromatic SMIs – aniline, pyrrole, and pyridine – for their ability to block Al<sub>2</sub>O<sub>3</sub> ALD on copper with (CuO<sub><i>x</i></sub>) and without (Cu) a native oxide. We find that pyrrole and aniline perform much better as inhibitors than pyridine does. Furthermore, when redosed on copper before every ALD cycle in an ABC scheme, pyrrole and aniline provide outstanding inhibition, facilitating the selective deposition of over 11 nm of Al<sub>2</sub>O<sub>3</sub> on an SiO<sub>2</sub> growth surface in the presence of Cu with 99.9% selectivity. By combining both theory and experiment, we provide new understanding of the mechanisms by which selectivity is prolonged and lost. First, we show that whereas pyrrole and aniline adsorb in a planar bonding orientation, pyridine binds upright at the copper surface, and we propose that the upright molecular orientation is the origin of the ineffective inhibition of pyridine. Second, we find that the CuO<sub><i>x</i></sub> surface is inherently more reactive than the Cu surface, leading to an eventual loss of selectivity, despite the redosing of the inhibitor. Finally, we observe that redosing of aniline protects the copper surface from undesired oxidation, whereas the redosing of pyridine does not. As such, we posit that a likely benefit of redosing is preventing oxidation and thus reducing reactive site formation during ALD. Through this work, we demonstrate the capability of nitrogenous aromatics to serve as SMIs for AS-ALD, and we contribute insights regarding the role of molecular orientation on inhibition and the impact of ALD process parameters on selectivity.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"23 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142849743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-18DOI: 10.1021/acs.chemmater.4c02301
Max C. Gallant, Matthew J. McDermott, Bryant Li, Kristin A. Persson
New computational tools for solid-state synthesis recipe design are needed in order to accelerate the experimental realization of novel functional materials proposed by high-throughput materials discovery workflows. This work contributes a cellular automaton simulation framework for predicting the time-dependent evolution of intermediate and product phases during solid-state reactions as a function of precursor choice and amount, reaction atmosphere, and heating profile. The simulation captures the effects of reactant particle spatial distribution, particle melting, and reaction atmosphere. Reaction rates based on rudimentary kinetics are estimated using density functional theory data from the Materials Project and machine learning estimators for the melting point and the vibrational entropy component of the Gibbs free energy. The resulting simulation framework allows for the prediction of the likely outcome of a reaction recipe before any experiments are performed. We analyze five experimental solid-state recipes for BaTiO3, CaZrN2, and YMnO3 found in the literature to illustrate the performance of the model in capturing reaction selectivity and reaction pathways as a function of temperature and precursor choice. This simulation framework offers an easier way to optimize existing recipes, aid in the identification of intermediates, and design effective recipes for yet unrealized inorganic solids in silico.
{"title":"A Cellular Automaton Simulation for Predicting Phase Evolution in Solid-State Reactions","authors":"Max C. Gallant, Matthew J. McDermott, Bryant Li, Kristin A. Persson","doi":"10.1021/acs.chemmater.4c02301","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02301","url":null,"abstract":"New computational tools for solid-state synthesis recipe design are needed in order to accelerate the experimental realization of novel functional materials proposed by high-throughput materials discovery workflows. This work contributes a cellular automaton simulation framework for predicting the time-dependent evolution of intermediate and product phases during solid-state reactions as a function of precursor choice and amount, reaction atmosphere, and heating profile. The simulation captures the effects of reactant particle spatial distribution, particle melting, and reaction atmosphere. Reaction rates based on rudimentary kinetics are estimated using density functional theory data from the Materials Project and machine learning estimators for the melting point and the vibrational entropy component of the Gibbs free energy. The resulting simulation framework allows for the prediction of the likely outcome of a reaction recipe before any experiments are performed. We analyze five experimental solid-state recipes for BaTiO<sub>3</sub>, CaZrN<sub>2</sub>, and YMnO<sub>3</sub> found in the literature to illustrate the performance of the model in capturing reaction selectivity and reaction pathways as a function of temperature and precursor choice. This simulation framework offers an easier way to optimize existing recipes, aid in the identification of intermediates, and design effective recipes for yet unrealized inorganic solids <i>in silico</i>.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"47 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-18DOI: 10.1021/acs.chemmater.4c02478
Haijin Ni, Lei Gao, Jinlong Zhu, Dubin Huang, Wen Yin, Ruqiang Zou, Changping Li, Songbai Han
Solid Li-ion conductors require high ionic conductivity to ensure rapid Li+ transport within solid-state batteries, necessitating a thorough examination of the relationship between the structure and Li+ transport mechanisms. Factors such as crystal symmetries, anion electronegativity, and Li-anion bond lengths are critical in influencing the ionic conductivities of solid conductors. Furthermore, the relationship between Li+ transport and the dynamic behavior of anions, particularly through mechanisms such as the paddle-wheel effect, highlights the complexity of ionic transport in solid conductors. In this study, we focus on investigating the antiperovskite-type ionic conductor Li2OHX (X = Cl or Br), which integrates various static structural features with dynamic anion behavior, to delve deeper into the structure–function relationship. Employing Rietveld refinement on neutron powder diffraction, maximum entropy method analysis, and ab initio molecular dynamics simulations, our findings reveal that Li+ transport is influenced not only by static structural properties like space groups, anion electronegativity, Li vacancies, and Li–O bond lengths but also, and more crucially, by the dynamics of OH– anions. These insights highlight the pivotal role of anion dynamics and offer foundational guidelines for designing solid ionic conductors.
{"title":"Exploring Ionic Transport Mechanisms in Solid Conductors: A Dual Perspective on Static Structural Properties and Anion Dynamics","authors":"Haijin Ni, Lei Gao, Jinlong Zhu, Dubin Huang, Wen Yin, Ruqiang Zou, Changping Li, Songbai Han","doi":"10.1021/acs.chemmater.4c02478","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02478","url":null,"abstract":"Solid Li-ion conductors require high ionic conductivity to ensure rapid Li<sup>+</sup> transport within solid-state batteries, necessitating a thorough examination of the relationship between the structure and Li<sup>+</sup> transport mechanisms. Factors such as crystal symmetries, anion electronegativity, and Li-anion bond lengths are critical in influencing the ionic conductivities of solid conductors. Furthermore, the relationship between Li<sup>+</sup> transport and the dynamic behavior of anions, particularly through mechanisms such as the paddle-wheel effect, highlights the complexity of ionic transport in solid conductors. In this study, we focus on investigating the antiperovskite-type ionic conductor Li<sub>2</sub>OHX (X = Cl or Br), which integrates various static structural features with dynamic anion behavior, to delve deeper into the structure–function relationship. Employing Rietveld refinement on neutron powder diffraction, maximum entropy method analysis, and ab initio molecular dynamics simulations, our findings reveal that Li<sup>+</sup> transport is influenced not only by static structural properties like space groups, anion electronegativity, Li vacancies, and Li–O bond lengths but also, and more crucially, by the dynamics of OH<sup>–</sup> anions. These insights highlight the pivotal role of anion dynamics and offer foundational guidelines for designing solid ionic conductors.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"54 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-17DOI: 10.1021/acs.chemmater.4c02784
Hyun-Min Kim, Goo Min Park, Donghyeok Shin, Seong Min Park, Yuri Kim, Yang-Hee Kim, Yongwoo Kim, Kyoungwon Park, Chae Woo Ryu, Heesun Yang
This study explores the role of residual halide ions (Cl, Br, and I) in modulating the optical and electronic properties of heterostructured InP quantum dots (QDs) with ZnSe/ZnS double shells. By synthesizing halide-containing InP cores using aminophosphine chemistry, we investigate the impact of surface halides on the energy levels of red-, amber-, and green-emissive InP QDs. X-ray photoelectron and ultraviolet photoelectron spectroscopic analyses confirm the presence of halides on the InP core surface, which induces surface dipole and shift energy levels. Our findings reveal that the interfacial Cl and Br ions cause significant alterations in the conduction and valence band energy levels, resulting in band gap reduction and a photoluminescence (PL) red shift in the heterostructured QDs. These effects are the most pronounced for Cl-containing red-emissive QDs, while green-emissive QDs with I ions exhibit negligible changes. These results provide new insights into how surface halide ligands at the core–shell interface influence the optical performance of InP-based heterostructures, offering potential pathways for tuning the properties of QDs for advanced optoelectronic applications.
{"title":"Modulation of Optical and Electronic Properties in InP Quantum Dots through Residual Halide Ions at the Heterostructural Interface","authors":"Hyun-Min Kim, Goo Min Park, Donghyeok Shin, Seong Min Park, Yuri Kim, Yang-Hee Kim, Yongwoo Kim, Kyoungwon Park, Chae Woo Ryu, Heesun Yang","doi":"10.1021/acs.chemmater.4c02784","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02784","url":null,"abstract":"This study explores the role of residual halide ions (Cl, Br, and I) in modulating the optical and electronic properties of heterostructured InP quantum dots (QDs) with ZnSe/ZnS double shells. By synthesizing halide-containing InP cores using aminophosphine chemistry, we investigate the impact of surface halides on the energy levels of red-, amber-, and green-emissive InP QDs. X-ray photoelectron and ultraviolet photoelectron spectroscopic analyses confirm the presence of halides on the InP core surface, which induces surface dipole and shift energy levels. Our findings reveal that the interfacial Cl and Br ions cause significant alterations in the conduction and valence band energy levels, resulting in band gap reduction and a photoluminescence (PL) red shift in the heterostructured QDs. These effects are the most pronounced for Cl-containing red-emissive QDs, while green-emissive QDs with I ions exhibit negligible changes. These results provide new insights into how surface halide ligands at the core–shell interface influence the optical performance of InP-based heterostructures, offering potential pathways for tuning the properties of QDs for advanced optoelectronic applications.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"50 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-17DOI: 10.1021/acs.chemmater.4c02160
A. K. M. Manjur Hossain, Joseph McBride, Masoumeh Mahmoudi Gahrouei, Sabin Gautam, Jefferson A. Carter, Piumi Indrachapa Samarawickrama, John F. Ackerman, Laura Rita de Sousa Oliveira, Jinke Tang, Jifa Tian, Brian M. Leonard
Recent research has demonstrated the potential for topological superconductivity, anisotropic Majorana bound states, optical nonlinearity, and enhanced electrochemical activity for transition metal dichalcogenides (TMDs) with a 2M structure. These unique TMD compounds exhibit metastability and, upon heating, undergo a transition to the thermodynamically stable 2H phase. The 2M phase is commonly made at high temperatures using traditional solid-state methods, and this metastability further complicates the growth of large 2M WS2 crystals. Herein, a novel synthetic method was developed, focusing on a molten salt reaction to synthesize large 2H crystals and then inducing transformation to the 2M phase through intercalation and thermal treatment. The 2H crystals were intercalated via a room-temperature sodium naphthalenide solution, producing a previously unreported Na-intercalated 2H WS2 phase. Thermal heating was required to facilitate the phase transition to the intercalated 2M crystal structure. This phase transition was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), electron dispersive X-ray spectroscopy (EDS), and Raman spectroscopy, which confirmed the synthesis of the intercalated 2M phase. Upon deintercalation, crystal and powder samples showed superconductivity with a Tc of 8.6–8.7 K, similar to previously reported values. The generality of this process was further demonstrated using alkali metal triethyl borohydride to intercalate 2H WS2 and produced the desired 2M phase. This novel synthetic method has broad implications for discovering metastable phases in other TMD families and layered materials. Separation of the intercalation and phase transition also has the potential to allow for large-scale synthesis of this technologically important phase with greater control over each step of the reaction.
{"title":"Intercalation-Induced Topotactic Phase Transformation of Tungsten Disulfide Crystals","authors":"A. K. M. Manjur Hossain, Joseph McBride, Masoumeh Mahmoudi Gahrouei, Sabin Gautam, Jefferson A. Carter, Piumi Indrachapa Samarawickrama, John F. Ackerman, Laura Rita de Sousa Oliveira, Jinke Tang, Jifa Tian, Brian M. Leonard","doi":"10.1021/acs.chemmater.4c02160","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02160","url":null,"abstract":"Recent research has demonstrated the potential for topological superconductivity, anisotropic Majorana bound states, optical nonlinearity, and enhanced electrochemical activity for transition metal dichalcogenides (TMDs) with a 2M structure. These unique TMD compounds exhibit metastability and, upon heating, undergo a transition to the thermodynamically stable 2H phase. The 2M phase is commonly made at high temperatures using traditional solid-state methods, and this metastability further complicates the growth of large 2M WS<sub>2</sub> crystals. Herein, a novel synthetic method was developed, focusing on a molten salt reaction to synthesize large 2H crystals and then inducing transformation to the 2M phase through intercalation and thermal treatment. The 2H crystals were intercalated via a room-temperature sodium naphthalenide solution, producing a previously unreported Na-intercalated 2H WS<sub>2</sub> phase. Thermal heating was required to facilitate the phase transition to the intercalated 2M crystal structure. This phase transition was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), electron dispersive X-ray spectroscopy (EDS), and Raman spectroscopy, which confirmed the synthesis of the intercalated 2M phase. Upon deintercalation, crystal and powder samples showed superconductivity with a <i>T</i><sub>c</sub> of 8.6–8.7 K, similar to previously reported values. The generality of this process was further demonstrated using alkali metal triethyl borohydride to intercalate 2H WS<sub>2</sub> and produced the desired 2M phase. This novel synthetic method has broad implications for discovering metastable phases in other TMD families and layered materials. Separation of the intercalation and phase transition also has the potential to allow for large-scale synthesis of this technologically important phase with greater control over each step of the reaction.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"43 2 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-17DOI: 10.1021/acs.chemmater.4c02271
Kristin L. Lewis, Jonathan D. Hoang, Michael F. Toney, Timothy J. White
Liquid crystalline elastomers (LCEs) are soft materials which disorder upon heating through the isotropic transition temperature. The order-disorder phase transition of LCEs results in a contraction of up to ∼50% along the aligned axis. Motivated by this distinctive stimuli-response, LCEs are increasingly considered as low-density actuators. Generally, LCEs are composed entirely of covalent bonds. Recently, we have prepared LCEs with intramesogenic supramolecular bonds from dimerized oxybenzoic acid derivatives and documented distinctive thermomechanical response in these supramolecular LCEs. Here, we report a detailed investigation of phase transitions in supramolecular LCEs by systematically varying the composition to affect the strength of the intermolecular interactions in the polymer network. The order-disorder phase transition is shown to be influenced by the conformation and dissociation of supramolecular dimers. Distinctly, this report isolates and details an LCE composition which undergoes an intermediate transition to an incommensurate phase at lower temperatures than the order-disorder transition.
{"title":"Order–Disorder Transition of Supramolecular Liquid Crystalline Elastomers","authors":"Kristin L. Lewis, Jonathan D. Hoang, Michael F. Toney, Timothy J. White","doi":"10.1021/acs.chemmater.4c02271","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02271","url":null,"abstract":"Liquid crystalline elastomers (LCEs) are soft materials which disorder upon heating through the isotropic transition temperature. The order-disorder phase transition of LCEs results in a contraction of up to ∼50% along the aligned axis. Motivated by this distinctive stimuli-response, LCEs are increasingly considered as low-density actuators. Generally, LCEs are composed entirely of covalent bonds. Recently, we have prepared LCEs with intramesogenic supramolecular bonds from dimerized oxybenzoic acid derivatives and documented distinctive thermomechanical response in these supramolecular LCEs. Here, we report a detailed investigation of phase transitions in supramolecular LCEs by systematically varying the composition to affect the strength of the intermolecular interactions in the polymer network. The order-disorder phase transition is shown to be influenced by the conformation and dissociation of supramolecular dimers. Distinctly, this report isolates and details an LCE composition which undergoes an intermediate transition to an incommensurate phase at lower temperatures than the order-disorder transition.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"19 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-16DOI: 10.1021/acs.chemmater.4c03025
Rohit Kumar Rohj, Animesh Bhui, Shaili Sett, Arindam Ghosh, Kanishka Biswas, D. D. Sarma
A comprehensive understanding of thermal transport is crucial for many applications, including heat dissipation systems, thermal barrier coatings, and harnessing potentials of thermoelectric materials. Here, we report an ultralow thermal conductivity, κ, in a p-type layered chalcogenide, TlCuZrSe3. Our investigation reveals that the anisotropic values of κ in two perpendicular directions in this compound vary between 0.88 and 0.41 Wm–1K–1 and 1.15–0.62 Wm–1K–1, respectively, over the temperature range of 295–600 K. The low-temperature specific heat data could only be explained by considering Einstein oscillator terms in addition to the conventional Debye model-based contributions, consistent with the presence of localized Tl1+ rattlers. The unique anisotropic crystal structure of TlCuZrSe3 and the rattling of Tl1+ ions lead to the generation of low-frequency phonons. These relatively flat optical phonon modes hybridize with acoustic phonons, giving rise to strong anharmonicity and phonon scattering channels. Raman spectroscopy confirms that these low-frequency phonon modes have extremely short lifetimes (∼1 ps), explaining the ultralow κ values, approaching the disordered limit, in this highly crystalline material.
{"title":"Ultralow Thermal Conductivity Approaching the Disordered Limit in Crystalline TlCuZrSe3","authors":"Rohit Kumar Rohj, Animesh Bhui, Shaili Sett, Arindam Ghosh, Kanishka Biswas, D. D. Sarma","doi":"10.1021/acs.chemmater.4c03025","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c03025","url":null,"abstract":"A comprehensive understanding of thermal transport is crucial for many applications, including heat dissipation systems, thermal barrier coatings, and harnessing potentials of thermoelectric materials. Here, we report an ultralow thermal conductivity, κ, in a p-type layered chalcogenide, TlCuZrSe<sub>3</sub>. Our investigation reveals that the anisotropic values of κ in two perpendicular directions in this compound vary between 0.88 and 0.41 Wm<sup>–1</sup>K<sup>–1</sup> and 1.15–0.62 Wm<sup>–1</sup>K<sup>–1</sup>, respectively, over the temperature range of 295–600 K. The low-temperature specific heat data could only be explained by considering Einstein oscillator terms in addition to the conventional Debye model-based contributions, consistent with the presence of localized Tl<sup>1+</sup> rattlers. The unique anisotropic crystal structure of TlCuZrSe<sub>3</sub> and the rattling of Tl<sup>1+</sup> ions lead to the generation of low-frequency phonons. These relatively flat optical phonon modes hybridize with acoustic phonons, giving rise to strong anharmonicity and phonon scattering channels. Raman spectroscopy confirms that these low-frequency phonon modes have extremely short lifetimes (∼1 ps), explaining the ultralow κ values, approaching the disordered limit, in this highly crystalline material.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"4 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-16DOI: 10.1021/acs.chemmater.4c02756
Xiliang Lian, Damien Dambournet, Mathieu Salanne
Solid-state ionic conductors are of primary importance for the design of tomorrow’s batteries. In lithium- or sodium-ion-based materials, the alkali cations diffuse through three-dimensional channels consisting of interconnected tetrahedral or octahedral sites with low free energy barriers between them. Fluoride ion conductors stand out in this landscape since the materials with the highest conductivities belong to the MSnF4 family (in which M2+ is a divalent cation), whose structure is layered and characterized by double-layers of Sn2+ and M2+ cations along a given direction. Importantly, these materials display stereoactive electron lone pairs (LPs) that seemingly play an important role not only in stabilizing the Sn–Sn layer but also in modulating the fluoride ion diffusive behavior. However, despite previous experimental and simulation studies, the involvement of the LPs in the fluoride ion conduction mechanism remains to be quantitatively understood. In this work, we simulate the BaSnF4 tetragonal structure using machine learning-based molecular dynamics, in which the interaction potential is trained on density functional theory data. We investigated the role of the Sn–LP–Sn layer in lowering the diffusion energy landscape. In particular, we show how the F– ions jump across this layer and occur much more frequently than in the Ba–F–Ba one, resulting in the formation of vacancies in the Ba–Sn layers. Concurrently, the LP stereochemical activity fluctuates to accommodate the F ions jumping. In addition, the presence of the LP layer enhances the flexibility of the Sn ions, which leads to an increase in two-dimensional diffusion by several orders of magnitude. These results contribute to our understanding of the interplay between LPs and ionic diffusion, helping to explain the good performance of the material in fluoride-ion batteries.
{"title":"Stereoactive Electron Lone Pairs Facilitate Fluoride Ion Diffusion in Tetragonal BaSnF4","authors":"Xiliang Lian, Damien Dambournet, Mathieu Salanne","doi":"10.1021/acs.chemmater.4c02756","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02756","url":null,"abstract":"Solid-state ionic conductors are of primary importance for the design of tomorrow’s batteries. In lithium- or sodium-ion-based materials, the alkali cations diffuse through three-dimensional channels consisting of interconnected tetrahedral or octahedral sites with low free energy barriers between them. Fluoride ion conductors stand out in this landscape since the materials with the highest conductivities belong to the MSnF<sub>4</sub> family (in which M<sup>2+</sup> is a divalent cation), whose structure is layered and characterized by double-layers of Sn<sup>2+</sup> and M<sup>2+</sup> cations along a given direction. Importantly, these materials display stereoactive electron lone pairs (LPs) that seemingly play an important role not only in stabilizing the Sn–Sn layer but also in modulating the fluoride ion diffusive behavior. However, despite previous experimental and simulation studies, the involvement of the LPs in the fluoride ion conduction mechanism remains to be quantitatively understood. In this work, we simulate the BaSnF<sub>4</sub> tetragonal structure using machine learning-based molecular dynamics, in which the interaction potential is trained on density functional theory data. We investigated the role of the Sn–LP–Sn layer in lowering the diffusion energy landscape. In particular, we show how the F<sup>–</sup> ions jump across this layer and occur much more frequently than in the Ba–F–Ba one, resulting in the formation of vacancies in the Ba–Sn layers. Concurrently, the LP stereochemical activity fluctuates to accommodate the F ions jumping. In addition, the presence of the LP layer enhances the flexibility of the Sn ions, which leads to an increase in two-dimensional diffusion by several orders of magnitude. These results contribute to our understanding of the interplay between LPs and ionic diffusion, helping to explain the good performance of the material in fluoride-ion batteries.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"88 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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