Noncentrosymmetry is the prerequisite for second-order nonlinear optical (NLO) activity, yet rationally converting centrosymmetric (CS) lattice into noncentrosymmetric (NCS) framework while simultaneously enhancing structural robustness remains nontrivial. Herein, we demonstrate a symmetry-breaking structural transformation from CS KInGeS4 to NCS KInGe2S6, in which the insertion of {[Ge2S7]6–}∞ chains disrupts the inversion symmetry in {[InGe2S6]−}∞ layers, and triggers a topological reorganization from layered architecture into a 3D framework. This architectural evolution endows the [InS4] tetrahedra with the highest degree of geometric distortion and the largest hyperpolarizability among known [InS4]-based functional building units. Crucially, KInGe2S6 exhibits a balanced set of favorable NLO performances, including a wide bandgap (Eg = 3.2 eV), phase matchable second-harmonic generation (0.4 × AgGaS2), moderate birefringence (Δn = 0.08@546 nm), and a high laser-induced damage threshold (7.18 × AgGaS2). First-principles calculations corroborate that the NLO effect originates primarily from the cooperative alignment of distorted [MS4] (M = In, Ge) tetrahedra. This work presents a strategy for developing high-performance mid-infrared NLO crystals through the synergistic control of dimensionality engineering and symmetry breaking.
{"title":"{[Ge2S7]6–}∞ Chains-Mediated Framework Reorganization Triggers Dimensional Upgrade and Infrared Nonlinear Optical Response","authors":"Wen-Rui Zhou, Zhen-Cheng Wu, Yong-Han Liu, Mao-Yin Ran, Sheng-Ping Guo","doi":"10.1021/acs.chemmater.6c00418","DOIUrl":"https://doi.org/10.1021/acs.chemmater.6c00418","url":null,"abstract":"Noncentrosymmetry is the prerequisite for second-order nonlinear optical (NLO) activity, yet rationally converting centrosymmetric (CS) lattice into noncentrosymmetric (NCS) framework while simultaneously enhancing structural robustness remains nontrivial. Herein, we demonstrate a symmetry-breaking structural transformation from CS KInGeS<sub>4</sub> to NCS KInGe<sub>2</sub>S<sub>6</sub>, in which the insertion of {[Ge<sub>2</sub>S<sub>7</sub>]<sup>6–</sup>}<sub>∞</sub> chains disrupts the inversion symmetry in {[InGe<sub>2</sub>S<sub>6</sub>]<sup>−</sup>}<sub>∞</sub> layers, and triggers a topological reorganization from layered architecture into a 3<i>D</i> framework. This architectural evolution endows the [InS<sub>4</sub>] tetrahedra with the highest degree of geometric distortion and the largest hyperpolarizability among known [InS<sub>4</sub>]-based functional building units. Crucially, KInGe<sub>2</sub>S<sub>6</sub> exhibits a balanced set of favorable NLO performances, including a wide bandgap (<i>E</i><sub>g</sub> = 3.2 eV), phase matchable second-harmonic generation (0.4 × AgGaS<sub>2</sub>), moderate birefringence (Δ<i>n</i> = 0.08@546 nm), and a high laser-induced damage threshold (7.18 × AgGaS<sub>2</sub>). First-principles calculations corroborate that the NLO effect originates primarily from the cooperative alignment of distorted [MS<sub>4</sub>] (M = In, Ge) tetrahedra. This work presents a strategy for developing high-performance mid-infrared NLO crystals through the synergistic control of dimensionality engineering and symmetry breaking.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"197 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147489678","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 : 2026-03-19DOI: 10.1021/acs.chemmater.5c03047
Mareike Dittmar, Julia Voß, Sebastian Hentschel, Lars Klemeyer, Dorota Koziej, Dennis Bonatz, Charlotte Ruhmlieb, Tobias Kipp, Alf Mews
We present a method for preparing NiPt-alloy tips on CdSe-core/CdS-shell dot-in-rod nanoparticles (DRs). The formation of the NiPt tips is separated into a two-step synthesis, where first Ni tips are grown, which then serve as nucleation sites for Pt before an alloying process occurs. Thus, the NiPt tips are formed in a seed-mediated approach. We find that the reactivity of the Ni tips can be controlled by oxygen treatment, while the reactivity of the lateral surface of the DRs can be tuned by ligands. Monitoring the growth dynamics of the NiPt reveals that an oxide layer on the Ni tips delays the nucleation of Pt, but it does not inevitably prevent it if a combination of oleic acid and oleylamine initiates oxide-layer conversion due to oleate formation. Without conversion, the oxide layer can be utilized to inhibit the NiPt formation. The choice of ligands can be exploited to enable or prevent separate Pt particle growth on the lateral semiconductor rod surface. Especially the DRs with NiPt-alloy tips show superior activity toward HER in both electrocatalytic and photocatalytic experiments.
{"title":"Seed-Mediated Synthesis of NiPt-Alloy-Tipped CdSe/CdS Nanocrystals for Photocatalysis","authors":"Mareike Dittmar, Julia Voß, Sebastian Hentschel, Lars Klemeyer, Dorota Koziej, Dennis Bonatz, Charlotte Ruhmlieb, Tobias Kipp, Alf Mews","doi":"10.1021/acs.chemmater.5c03047","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c03047","url":null,"abstract":"We present a method for preparing NiPt-alloy tips on CdSe-core/CdS-shell dot-in-rod nanoparticles (DRs). The formation of the NiPt tips is separated into a two-step synthesis, where first Ni tips are grown, which then serve as nucleation sites for Pt before an alloying process occurs. Thus, the NiPt tips are formed in a seed-mediated approach. We find that the reactivity of the Ni tips can be controlled by oxygen treatment, while the reactivity of the lateral surface of the DRs can be tuned by ligands. Monitoring the growth dynamics of the NiPt reveals that an oxide layer on the Ni tips delays the nucleation of Pt, but it does not inevitably prevent it if a combination of oleic acid and oleylamine initiates oxide-layer conversion due to oleate formation. Without conversion, the oxide layer can be utilized to inhibit the NiPt formation. The choice of ligands can be exploited to enable or prevent separate Pt particle growth on the lateral semiconductor rod surface. Especially the DRs with NiPt-alloy tips show superior activity toward HER in both electrocatalytic and photocatalytic experiments.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"85 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147490164","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 : 2026-03-19DOI: 10.1021/acs.chemmater.5c03187
Seungjun Cha, Courtney Brea, Aaron Malinoski, Chen Wang, Guoxiang Hu
Passivation of surface defects of cesium lead halide (CsPbX3, X = Cl, Br, I) nanocrystals is crucial to improving the stability and photoluminescence of these materials for further optoelectronic applications. Many ligands have been examined for surface passivation; however, a ligand design principle for improved photoluminescence quantum yield (PLQY) is still not available. Here, we report a combined computational and experimental study to systematically investigate 27 commercially available ligands and develop foundational guidelines. Using first-principles density functional theory, we calculated the binding energy of the ligands on the CsPbBr3 nanocrystal. We find a volcano relationship between ligand binding energy and the experimental PLQY, which reveals the negative impact of overly strong binding energy. We further perform electronic structure analysis and time-resolved optical spectroscopy to reveal that these strong-binding ligands can withdraw more electrons from the surface and induce trap states within the bandgap. With this, we develop a design principle for the PLQY of CsPbBr3 nanocrystals, highlighting the importance of the ligand binding energy comparable to that of the native halide species. We further applied this design principle to quantum-confined CsPbCl3 and CsPbI3 nanocrystals, and our computational predictions have been successfully validated by experiments.
卤化铯铅（CsPbX3, X = Cl, Br， I）纳米晶体表面缺陷的钝化是提高材料稳定性和光致发光性能的关键。许多配体已被检测表面钝化；然而，提高光致发光量子产率（PLQY）的配体设计原理仍然不可用。在这里，我们报告了一项结合计算和实验的研究，系统地调查了27种商业上可用的配体，并制定了基本的指导方针。利用第一性原理密度泛函理论，计算了配体在CsPbBr3纳米晶体上的结合能。我们发现配体结合能与实验PLQY呈火山关系，揭示了结合能过强的负面影响。我们进一步进行了电子结构分析和时间分辨光学光谱分析，揭示了这些强结合配体可以从表面提取更多的电子，并在带隙内诱导陷阱态。在此基础上，我们提出了CsPbBr3纳米晶体PLQY的设计原则，强调了配体结合能与天然卤化物相媲美的重要性。我们进一步将这一设计原理应用于量子受限的CsPbCl3和CsPbI3纳米晶体，并通过实验成功验证了我们的计算预测。
{"title":"Design Principles for Surface-Passivating Ligands of Cesium Lead Halide Perovskite Nanocrystals in the Strongly Quantum-Confined Regime","authors":"Seungjun Cha, Courtney Brea, Aaron Malinoski, Chen Wang, Guoxiang Hu","doi":"10.1021/acs.chemmater.5c03187","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c03187","url":null,"abstract":"Passivation of surface defects of cesium lead halide (CsPbX<sub>3</sub>, X = Cl, Br, I) nanocrystals is crucial to improving the stability and photoluminescence of these materials for further optoelectronic applications. Many ligands have been examined for surface passivation; however, a ligand design principle for improved photoluminescence quantum yield (PLQY) is still not available. Here, we report a combined computational and experimental study to systematically investigate 27 commercially available ligands and develop foundational guidelines. Using first-principles density functional theory, we calculated the binding energy of the ligands on the CsPbBr<sub>3</sub> nanocrystal. We find a volcano relationship between ligand binding energy and the experimental PLQY, which reveals the negative impact of overly strong binding energy. We further perform electronic structure analysis and time-resolved optical spectroscopy to reveal that these strong-binding ligands can withdraw more electrons from the surface and induce trap states within the bandgap. With this, we develop a design principle for the PLQY of CsPbBr<sub>3</sub> nanocrystals, highlighting the importance of the ligand binding energy comparable to that of the native halide species. We further applied this design principle to quantum-confined CsPbCl<sub>3</sub> and CsPbI<sub>3</sub> nanocrystals, and our computational predictions have been successfully validated by experiments.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"54 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147489676","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 : 2026-03-19DOI: 10.1021/acs.chemmater.5c03118
Islamiyat Ojelade, Erica Truong, Tej P. Poudel, Sawankumar Patel, Pawan K. Ojha, Yudan Chen, Ifeoluwa Oyekunle, Yongkang Jin, Md Mahinur Islam, Tehreem Toheed, Hannah Matos-Pimentel, Joey Peterson, Yan-Yan Hu
Slow cooling and heating cycles at relatively low temperatures (25 to 100 °C) are demonstrated to be an effective and practical strategy for improving ionic conductivity in oxyhalide, halide, and thiophosphate glass-ceramic electrolytes. In this study, Li3PO4–LiI, Li3YBr6, and Li3PS4 were chosen as the representative systems. Thermal conditioning improves Li+-ion conduction by over 40%. Advanced characterizations using high-resolution NMR and XRD reveal four underlying mechanisms responsible for the increase in ionic conductivity, including the removal of low-conductivity impurities, the formation of high-conductivity phases, modification of the anion network, active cation redistribution, and enhanced ion mobility.
{"title":"Thermal Conditioning: An Effective and Inexpensive Strategy for Enhancing Ion Transport in Glass-Ceramics","authors":"Islamiyat Ojelade, Erica Truong, Tej P. Poudel, Sawankumar Patel, Pawan K. Ojha, Yudan Chen, Ifeoluwa Oyekunle, Yongkang Jin, Md Mahinur Islam, Tehreem Toheed, Hannah Matos-Pimentel, Joey Peterson, Yan-Yan Hu","doi":"10.1021/acs.chemmater.5c03118","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c03118","url":null,"abstract":"Slow cooling and heating cycles at relatively low temperatures (25 to 100 °C) are demonstrated to be an effective and practical strategy for improving ionic conductivity in oxyhalide, halide, and thiophosphate glass-ceramic electrolytes. In this study, Li<sub>3</sub>PO<sub>4</sub>–LiI, Li<sub>3</sub>YBr<sub>6</sub>, and Li<sub>3</sub>PS<sub>4</sub> were chosen as the representative systems. Thermal conditioning improves Li<sup>+</sup>-ion conduction by over 40%. Advanced characterizations using high-resolution NMR and XRD reveal four underlying mechanisms responsible for the increase in ionic conductivity, including the removal of low-conductivity impurities, the formation of high-conductivity phases, modification of the anion network, active cation redistribution, and enhanced ion mobility.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"10 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147489675","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 : 2026-03-19DOI: 10.1021/acs.chemmater.6c00046
Richie Fong, Pablo Trevino Lara, Nauman Mubarak, Yixuan Zhang, Sang-Jun Lee, Dong-Hwa Seo, Jinhyuk Lee
Disordered rock-salt (DRX) cathodes have emerged as promising candidates for low-cost, high-energy lithium-ion batteries that are free of nickel and cobalt. However, their practical use is hindered by rapid capacity and voltage degradation during cycling. This degradation has largely been attributed to chemical instability at high charge states, where unstable oxygen oxidation leads to oxygen loss, electrolyte decomposition, and transition metal dissolution. Recently, mechanical instability has been recognized as a key issue, driven by large volume changes in DRX particles that induce composite electrode-level cracks and pores. Here, through combined in situ and ex situ characterization with density functional theory calculations and machine learning applied to a model DRX compound, Li1.2Mn0.6Nb0.2O2, we demonstrate that irreversible oxygen loss triggers cascading lattice expansion in DRX, establishing strong coupling between chemical and mechanical instabilities that leads to composite electrode damage and accelerated performance degradation. Notably, we show that this coupled degradation pathway can be significantly mitigated by employing a highly concentrated electrolyte, which suppresses oxygen loss and stabilizes the DRX structure. These findings provide a more complete understanding of DRX degradation and highlight electrolyte engineering as a key strategy to improve the durability of high-energy DRX cathodes across material, composite electrode, and cell levels.
{"title":"Suppressing Oxygen-Loss-Driven Lattice Expansion Cascades in Disordered Rock-Salt Li-Ion Cathodes via Electrolyte Engineering","authors":"Richie Fong, Pablo Trevino Lara, Nauman Mubarak, Yixuan Zhang, Sang-Jun Lee, Dong-Hwa Seo, Jinhyuk Lee","doi":"10.1021/acs.chemmater.6c00046","DOIUrl":"https://doi.org/10.1021/acs.chemmater.6c00046","url":null,"abstract":"Disordered rock-salt (DRX) cathodes have emerged as promising candidates for low-cost, high-energy lithium-ion batteries that are free of nickel and cobalt. However, their practical use is hindered by rapid capacity and voltage degradation during cycling. This degradation has largely been attributed to chemical instability at high charge states, where unstable oxygen oxidation leads to oxygen loss, electrolyte decomposition, and transition metal dissolution. Recently, mechanical instability has been recognized as a key issue, driven by large volume changes in DRX particles that induce composite electrode-level cracks and pores. Here, through combined in situ and ex situ characterization with density functional theory calculations and machine learning applied to a model DRX compound, Li<sub>1.2</sub>Mn<sub>0.6</sub>Nb<sub>0.2</sub>O<sub>2</sub>, we demonstrate that irreversible oxygen loss triggers cascading lattice expansion in DRX, establishing strong coupling between chemical and mechanical instabilities that leads to composite electrode damage and accelerated performance degradation. Notably, we show that this coupled degradation pathway can be significantly mitigated by employing a highly concentrated electrolyte, which suppresses oxygen loss and stabilizes the DRX structure. These findings provide a more complete understanding of DRX degradation and highlight electrolyte engineering as a key strategy to improve the durability of high-energy DRX cathodes across material, composite electrode, and cell levels.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"49 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147490165","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 : 2026-03-19DOI: 10.1021/acs.chemmater.5c03323
Maria Maniadi, Marie Guesdon, Kostiantyn Tieriekhov, Aseem Rajan Kshirsagar, Davide Spirito, Beatriz Martín-García, Nicolas Mercier, Oriol Arteaga, Mikaël Kepenekian, Claudine Katan, Alexandre Abhervé
With the emergence of chiral hybrid metal-halide and low-dimensional halide perovskite materials, the propensity to generate polarized electroluminescence in LED devices using this family of hybrid semiconductors is questioned. To evaluate this potential, some efforts have been undertaken in order to reveal their intrinsic circularly polarized luminescence (CPL) in either the single-crystal or thin-film state. However, the strong anisotropy in the optical properties of such highly crystalline materials can affect CPL measurements, especially in biaxial compounds, leading to the dominance of artifacts and/or CPL of macroscopic origin, which have been sometimes overlooked. Here, we wish to investigate the origins of CPL signals recorded using one-dimensional compounds of the general formula (A)PbBr3 (A = monovalent cation). To achieve this, we complement the crystal structure determination with optical property analysis (photoluminescence and circular dichroism), Raman spectroscopy, and computational modeling. CPL measurements reveal that the circularly polarized signal is dominated by the combination of linearly polarized optical effects from the sample and the detection system (i.e., artifacts), while the combination of two linearly polarized optical phenomena from the sample could give rise to nonreciprocal CPL, i.e., a reproducible CPL that is dependent on the direction of propagation. This study suggests that, with a careful choice of organic cation, chiral hybrid metal-halides could afford reciprocal CPL with glum values lying in the 10–3 order of magnitude, a degree of polarization that might be increased in electroluminescence due to the presence of nonreciprocal effects.
{"title":"On the Origin of Circularly Polarized Luminescence in Chiral One-Dimensional (A)PbBr3 Single Crystals","authors":"Maria Maniadi, Marie Guesdon, Kostiantyn Tieriekhov, Aseem Rajan Kshirsagar, Davide Spirito, Beatriz Martín-García, Nicolas Mercier, Oriol Arteaga, Mikaël Kepenekian, Claudine Katan, Alexandre Abhervé","doi":"10.1021/acs.chemmater.5c03323","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c03323","url":null,"abstract":"With the emergence of chiral hybrid metal-halide and low-dimensional halide perovskite materials, the propensity to generate polarized electroluminescence in LED devices using this family of hybrid semiconductors is questioned. To evaluate this potential, some efforts have been undertaken in order to reveal their intrinsic circularly polarized luminescence (CPL) in either the single-crystal or thin-film state. However, the strong anisotropy in the optical properties of such highly crystalline materials can affect CPL measurements, especially in biaxial compounds, leading to the dominance of artifacts and/or CPL of macroscopic origin, which have been sometimes overlooked. Here, we wish to investigate the origins of CPL signals recorded using one-dimensional compounds of the general formula (A)PbBr<sub>3</sub> (A = monovalent cation). To achieve this, we complement the crystal structure determination with optical property analysis (photoluminescence and circular dichroism), Raman spectroscopy, and computational modeling. CPL measurements reveal that the circularly polarized signal is dominated by the combination of linearly polarized optical effects from the sample and the detection system (i.e., artifacts), while the combination of two linearly polarized optical phenomena from the sample could give rise to nonreciprocal CPL, i.e., a reproducible CPL that is dependent on the direction of propagation. This study suggests that, with a careful choice of organic cation, chiral hybrid metal-halides could afford reciprocal CPL with <i>g</i><sub>lum</sub> values lying in the 10<sup>–3</sup> order of magnitude, a degree of polarization that might be increased in electroluminescence due to the presence of nonreciprocal effects.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"13 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147489677","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 : 2026-03-19DOI: 10.1021/acs.chemmater.5c03454
Eliza K. Price, Seryio Saris, Angelina Rogatch, Jimin Kwag, Anna C. Clark, Gergely Nagy, William A. Tisdale
The surface termination and ligand passivation of semiconducting nanocrystals (NCs) impact the stability, optical properties, and self-assembly of NCs. In this work, we definitively characterize the surface of lead sulfide (PbS) NCs synthesized from excess PbCl2. With a combination of small-angle neutron scattering (SANS), photoluminescence, and 1D and 2D NMR experiments, we show that the surface termination of PbS NCs depends on the presence of PbCl2 during ligand exchange. When excess PbCl2 is removed prior to ligand exchange, PbS[RNH3+Cl–] NCs are obtained, which are terminated by a monolayer of PbClx on the {100}PbS facet and passivated by oleylammonium chloride ligands. On the other hand, when excess PbCl2 remains in solution during ligand exchange, lead oleate forms and attaches to the {111}PbS facets of PbS[RNH3+Cl–] NCs, creating PbS@PbClx NCs. PbS@PbClx NCs are coated in an epitaxial layer of PbClx on both the {100}PbS and {111}PbS facets, making them 0.3–0.4 nm larger on average than PbS[RNH3+Cl–] NCs with identical absorption wavelengths. Additionally, PbS@PbClx NCs have a consistently higher photoluminescence quantum yield and longer photoluminescence lifetimes than PbS[RNH3+Cl–] NCs. This study clarifies the surface structure of PbS NCs synthesized from excess PbCl2, highlighting ligand exchange strategies and reconciling observations from across the literature.
{"title":"Variable Surface Termination and Ligand Passivation of Lead Sulfide Nanocrystals Synthesized with Excess Lead Chloride","authors":"Eliza K. Price, Seryio Saris, Angelina Rogatch, Jimin Kwag, Anna C. Clark, Gergely Nagy, William A. Tisdale","doi":"10.1021/acs.chemmater.5c03454","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c03454","url":null,"abstract":"The surface termination and ligand passivation of semiconducting nanocrystals (NCs) impact the stability, optical properties, and self-assembly of NCs. In this work, we definitively characterize the surface of lead sulfide (PbS) NCs synthesized from excess PbCl<sub>2</sub>. With a combination of small-angle neutron scattering (SANS), photoluminescence, and 1D and 2D NMR experiments, we show that the surface termination of PbS NCs depends on the presence of PbCl<sub>2</sub> during ligand exchange. When excess PbCl<sub>2</sub> is removed prior to ligand exchange, PbS[RNH<sub>3</sub><sup>+</sup>Cl<sup>–</sup>] NCs are obtained, which are terminated by a monolayer of PbCl<sub><i>x</i></sub> on the {100}<sub>PbS</sub> facet and passivated by oleylammonium chloride ligands. On the other hand, when excess PbCl<sub>2</sub> remains in solution during ligand exchange, lead oleate forms and attaches to the {111}<sub>PbS</sub> facets of PbS[RNH<sub>3</sub><sup>+</sup>Cl<sup>–</sup>] NCs, creating PbS@PbCl<sub><i>x</i></sub> NCs. PbS@PbCl<sub><i>x</i></sub> NCs are coated in an epitaxial layer of PbCl<sub><i>x</i></sub> on both the {100}<sub>PbS</sub> and {111}<sub>PbS</sub> facets, making them 0.3–0.4 nm larger on average than PbS[RNH<sub>3</sub><sup>+</sup>Cl<sup>–</sup>] NCs with identical absorption wavelengths. Additionally, PbS@PbCl<sub><i>x</i></sub> NCs have a consistently higher photoluminescence quantum yield and longer photoluminescence lifetimes than PbS[RNH<sub>3</sub><sup>+</sup>Cl<sup>–</sup>] NCs. This study clarifies the surface structure of PbS NCs synthesized from excess PbCl<sub>2,</sub> highlighting ligand exchange strategies and reconciling observations from across the literature.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"1 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147492869","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 : 2026-03-18DOI: 10.1021/acs.chemmater.6c00089
Shradha R. Joshi, Martin A. Schroer, Markus Winterer
The design of nanoparticles (NPs) with dedicated material properties relevant for specific applications relies on a fundamental understanding of the underlying (trans-)formation mechanisms. Combining experimental observations during particle formation with corresponding simulations offers mechanistic insights necessary to optimize particle characteristics. Chemical vapor synthesis (CVS) is a gas-phase NP synthesis technique enabling scalable production of NPs with desired characteristics. The time–temperature, T(t), profile of the CVS reaction mainly governs the (trans-)formation of NPs. Ex situ investigations to determine correlations between process parameters and particle characteristics often suffer from information loss due to aging or oxidation of transient species, aggregation, or preferred orientations of nanocrystals. These discrepancies may be avoided by in situ and operando probing: where and while the particles are formed. Here, we report results on in situ X-ray diffraction of tin oxide (SnO2) NPs during CVS using synchrotron radiation to observe the evolving crystal structure as the particles form and grow. Especially, the influence of the T(t) profile on the crystal structure of NPs is investigated in situ. Experimental results are complemented by simulations using a physicochemical model of the CVS process. Combining in situ and operando experiments with simulations uncovers the underlying (trans-)formation mechanisms and indicates a dynamic evolution of NP structures. Additionally, temperatures of the nanocrystals in the CVS process are determined by Rietveld refinement of the in situ and operando XRD data via thermal expansion of the lattice parameters.
{"title":"Observing Structural Evolution of Tin Oxide Nanocrystals during Chemical Vapor Synthesis by In Situ and Operando X-ray Diffraction","authors":"Shradha R. Joshi, Martin A. Schroer, Markus Winterer","doi":"10.1021/acs.chemmater.6c00089","DOIUrl":"https://doi.org/10.1021/acs.chemmater.6c00089","url":null,"abstract":"The design of nanoparticles (NPs) with dedicated material properties relevant for specific applications relies on a fundamental understanding of the underlying (trans-)formation mechanisms. Combining experimental observations during particle formation with corresponding simulations offers mechanistic insights necessary to optimize particle characteristics. Chemical vapor synthesis (CVS) is a gas-phase NP synthesis technique enabling scalable production of NPs with desired characteristics. The time–temperature, <i>T(t)</i>, profile of the CVS reaction mainly governs the (trans-)formation of NPs. Ex situ investigations to determine correlations between process parameters and particle characteristics often suffer from information loss due to aging or oxidation of transient species, aggregation, or preferred orientations of nanocrystals. These discrepancies may be avoided by in situ and operando probing: <i>where</i> and <i>while</i> the particles are formed. Here, we report results on in situ X-ray diffraction of tin oxide (SnO<sub>2</sub>) NPs during CVS using synchrotron radiation to observe the evolving crystal structure as the particles form and grow. Especially, the influence of the <i>T(t)</i> profile on the crystal structure of NPs is investigated in situ. Experimental results are complemented by simulations using a physicochemical model of the CVS process. Combining in situ and operando experiments with simulations uncovers the underlying (trans-)formation mechanisms and indicates a dynamic evolution of NP structures. Additionally, temperatures of the nanocrystals in the CVS process are determined by Rietveld refinement of the in situ and operando XRD data via thermal expansion of the lattice parameters.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"17 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147471771","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 : 2026-03-18DOI: 10.1021/acs.chemmater.5c03167
Chao Zeng, Haoliang Liu, Shangyong Wu, Huaxuan He, Guodong Meng, Le Shi, Kai Wu, Yonghong Cheng, Bing Xiao
The synthesis of phase-pure out-of-plane ordered MAX phases (o-MAX) Cr2VAlC2 and Cr2V2AlC3 is notoriously challenging and often hindered by parasitic reactions inherent to conventional elemental powder routes. This work combines thermodynamic calculations with experimental synthesis to validate the proposed solid-state reaction pathways employing Cr2AlC and VC as starting compositions to prepare high-purity o-Cr2VAlC2 and o-Cr2V2AlC3 MAX phases in the Cr–V–Al-C system. The thermodynamic formability of 312 and 413 MAX phases is evaluated by calculating the formation enthalpies and Gibbs free energies for both fully ordered o-MAX phases and their corresponding solid solutions, confirming the high thermodynamic stability of o-MAX compounds in comparison to solid solution forms from both typical elemental powder metallurgy and solid-state reaction synthesis. Combining the linear programming optimization algorithm for reaction thermodynamics and the systematic experimental verifications of phase formation kinetics, high yields of o-Cr2VAlC2 (82.0 wt %) and o-Cr2V2AlC3 (88.7 wt %) MAX phases are obtained with starting compositions as Cr2AlC/VC = 1:1.2 and 1:1.9 at the sintering temperature of 1500 °C. Using the JMAK equation, the apparent activation energies for phase nucleation and growth of o-Cr2VAlC2 and o-Cr2V2AlC3 phases are found to be 313.6 and 98.4 kJ mol–1, respectively. The calculated electronic density of states and bond orders for solid solutions and fully ordered MAX phases confirm that the stabilization of higher-order o-MAX phases in the Cr–V–Al-C system is mainly attributed to the significant reduction of Cr–C and V–C bond orders for those antisite atoms in disordered structures. This work elucidates a new pragmatic strategy to precisely tailor both reaction thermodynamics and kinetics for the synthesis of o-MAX phases in general.
{"title":"Reaction Thermodynamics and Kinetics of Solid-State Reaction Synthesis for High-Purity Out-of-Plane Ordered Cr2VAlC2 and Cr2V2AlC3 MAX Phases","authors":"Chao Zeng, Haoliang Liu, Shangyong Wu, Huaxuan He, Guodong Meng, Le Shi, Kai Wu, Yonghong Cheng, Bing Xiao","doi":"10.1021/acs.chemmater.5c03167","DOIUrl":"https://doi.org/10.1021/acs.chemmater.5c03167","url":null,"abstract":"The synthesis of phase-pure out-of-plane ordered MAX phases (o-MAX) Cr<sub>2</sub>VAlC<sub>2</sub> and Cr<sub>2</sub>V<sub>2</sub>AlC<sub>3</sub> is notoriously challenging and often hindered by parasitic reactions inherent to conventional elemental powder routes. This work combines thermodynamic calculations with experimental synthesis to validate the proposed solid-state reaction pathways employing Cr<sub>2</sub>AlC and VC as starting compositions to prepare high-purity o-Cr<sub>2</sub>VAlC<sub>2</sub> and o-Cr<sub>2</sub>V<sub>2</sub>AlC<sub>3</sub> MAX phases in the Cr–V–Al-C system. The thermodynamic formability of 312 and 413 MAX phases is evaluated by calculating the formation enthalpies and Gibbs free energies for both fully ordered o-MAX phases and their corresponding solid solutions, confirming the high thermodynamic stability of o-MAX compounds in comparison to solid solution forms from both typical elemental powder metallurgy and solid-state reaction synthesis. Combining the linear programming optimization algorithm for reaction thermodynamics and the systematic experimental verifications of phase formation kinetics, high yields of o-Cr<sub>2</sub>VAlC<sub>2</sub> (82.0 wt %) and o-Cr<sub>2</sub>V<sub>2</sub>AlC<sub>3</sub> (88.7 wt %) MAX phases are obtained with starting compositions as Cr<sub>2</sub>AlC/VC = 1:1.2 and 1:1.9 at the sintering temperature of 1500 °C. Using the JMAK equation, the apparent activation energies for phase nucleation and growth of o-Cr<sub>2</sub>VAlC<sub>2</sub> and o-Cr<sub>2</sub>V<sub>2</sub>AlC<sub>3</sub> phases are found to be 313.6 and 98.4 kJ mol<sup>–1</sup>, respectively. The calculated electronic density of states and bond orders for solid solutions and fully ordered MAX phases confirm that the stabilization of higher-order o-MAX phases in the Cr–V–Al-C system is mainly attributed to the significant reduction of Cr–C and V–C bond orders for those antisite atoms in disordered structures. This work elucidates a new pragmatic strategy to precisely tailor both reaction thermodynamics and kinetics for the synthesis of o-MAX phases in general.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"52 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147471772","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 : 2026-03-17DOI: 10.1021/acs.chemmater.6c00114
Ming Jiang, Aopeng Song, Yigang Yan, Wenqian Feng, Hongjiao Li, Bin Liang
Precise identification of high-entropy alloys (HEAs) from the vast chemical space remains a challenge across various application fields. Focusing on HEAs for hydrogen storage, this study investigates the applicability and limitations of the physically intuitive hydrogen affinity (ΔHaff) as an energetic descriptor for predicting the macroscopic performance, using comprehensive density functional theory simulations, statistical sampling, and experimental validation of V–Ti-based HEAs. Results reveal a near-equal thermodynamic preference for tetrahedral and octahedral hydrogen occupation sites in BCC HEAs and element-specific hydrogen selectivity at low concentrations. The developed ΔHaff descriptor exhibits strong linear correlations with hydrogen binding energy and hydride formation enthalpy, establishing a design principle targeting a medium ΔHaff value of approximately −25 kJ/mol H. Guided by this principle and Hume–Rothery rules, nine HEAs were designed and experimentally validated. Among them, V3Ti3Cr2Fe2 emerged as a promising candidate, demonstrating a reversible capacity of 2.1 wt % at room temperature. Together with literature data, ΔHaff shows a robust linear relationship with mean metallic radius as well as hydride desorption temperature for BCC alloys but fails to correlate with storage capacity. The limitation is mainly rooted in secondary phase formation, surface deactivation as well as significant selectivity of hydrogen binding at low H/M ratios. This work provides atomic insights into the mechanisms governing HEA performance and establishes directions for complex systems subject to multifaceted influences.
{"title":"Applicability and Limitations of Hydrogen Affinity As a Descriptor for Designing High-Entropy Alloys for Hydrogen Storage","authors":"Ming Jiang, Aopeng Song, Yigang Yan, Wenqian Feng, Hongjiao Li, Bin Liang","doi":"10.1021/acs.chemmater.6c00114","DOIUrl":"https://doi.org/10.1021/acs.chemmater.6c00114","url":null,"abstract":"Precise identification of high-entropy alloys (HEAs) from the vast chemical space remains a challenge across various application fields. Focusing on HEAs for hydrogen storage, this study investigates the applicability and limitations of the physically intuitive hydrogen affinity (Δ<i>H</i><sub>aff</sub>) as an energetic descriptor for predicting the macroscopic performance, using comprehensive density functional theory simulations, statistical sampling, and experimental validation of V–Ti-based HEAs. Results reveal a near-equal thermodynamic preference for tetrahedral and octahedral hydrogen occupation sites in BCC HEAs and element-specific hydrogen selectivity at low concentrations. The developed Δ<i>H</i><sub>aff</sub> descriptor exhibits strong linear correlations with hydrogen binding energy and hydride formation enthalpy, establishing a design principle targeting a medium Δ<i>H</i><sub>aff</sub> value of approximately −25 kJ/mol H. Guided by this principle and Hume–Rothery rules, nine HEAs were designed and experimentally validated. Among them, V<sub>3</sub>Ti<sub>3</sub>Cr<sub>2</sub>Fe<sub>2</sub> emerged as a promising candidate, demonstrating a reversible capacity of 2.1 wt % at room temperature. Together with literature data, Δ<i>H</i><sub>aff</sub> shows a robust linear relationship with mean metallic radius as well as hydride desorption temperature for BCC alloys but fails to correlate with storage capacity. The limitation is mainly rooted in secondary phase formation, surface deactivation as well as significant selectivity of hydrogen binding at low H/M ratios. This work provides atomic insights into the mechanisms governing HEA performance and establishes directions for complex systems subject to multifaceted influences.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"11 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2026-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147466052","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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