In the design of near-infrared (NIR)-absorbing organic semiconductors, not only chromophoric π-conjugated backbones that govern the molecular electronic structures but also solubilizing substituents, which can significantly affect the solid-state packing structures, are crucial factors in tailoring solid-state optical and electrical properties as well as solution processability. In this study, we systematically investigated the structures and properties of a series of core- and end-alkylated donor–acceptor–donor triads based on a naphthodithiophenedione acceptor to elucidate the impact of the alkylation site on their solid-state structures and properties. Although the alkylation site marginally affects their molecular electronic structures, all of the core-alkylated triads showed significant red shifts of the main absorption band from the solution to the solid state, in sharp contrast to the blue shifts observed for the end-alkylated triads. Single-crystal X-ray analysis and thin-film X-ray diffraction revealed that the contrasting solid-state optical properties are likely attributed to the distinctly different arrangements of the chromophores in the solid state, depending on the alkylation site. The end-alkylated triads tend to form interchromophore cofacial and/or side-by-side arrangements, which results in the blue shift of absorption bands, whereas the core-alkylated triads tend to avoid such interchromophore arrangement and rather promote an in-plane orientation of the transition electric dipole moments in a slip-stacking manner, which leads to the red shift of absorption bands. Furthermore, the alkyl groups on the core effectively reduce the core-to-core interaction, thus improving the solubility of materials without compromising carrier transport properties. These results provide valuable insights into molecular design for developing solution-processable NIR-absorbing organic semiconductors.
{"title":"Core- versus End-Alkylation: Tailoring Solid-State Structures and Properties of Near-Infrared-Absorbing Organic Semiconductors Based on Naphthodithiophenediones","authors":"Kohsuke Kawabata, Kiyohito Mashimo, Kazuo Takimiya","doi":"10.1021/acs.chemmater.4c02436","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02436","url":null,"abstract":"In the design of near-infrared (NIR)-absorbing organic semiconductors, not only chromophoric π-conjugated backbones that govern the molecular electronic structures but also solubilizing substituents, which can significantly affect the solid-state packing structures, are crucial factors in tailoring solid-state optical and electrical properties as well as solution processability. In this study, we systematically investigated the structures and properties of a series of core- and end-alkylated donor–acceptor–donor triads based on a naphthodithiophenedione acceptor to elucidate the impact of the alkylation site on their solid-state structures and properties. Although the alkylation site marginally affects their molecular electronic structures, all of the core-alkylated triads showed significant red shifts of the main absorption band from the solution to the solid state, in sharp contrast to the blue shifts observed for the end-alkylated triads. Single-crystal X-ray analysis and thin-film X-ray diffraction revealed that the contrasting solid-state optical properties are likely attributed to the distinctly different arrangements of the chromophores in the solid state, depending on the alkylation site. The end-alkylated triads tend to form interchromophore cofacial and/or side-by-side arrangements, which results in the blue shift of absorption bands, whereas the core-alkylated triads tend to avoid such interchromophore arrangement and rather promote an in-plane orientation of the transition electric dipole moments in a slip-stacking manner, which leads to the red shift of absorption bands. Furthermore, the alkyl groups on the core effectively reduce the core-to-core interaction, thus improving the solubility of materials without compromising carrier transport properties. These results provide valuable insights into molecular design for developing solution-processable NIR-absorbing organic semiconductors.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"15 2 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142777284","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 : 2024-12-04DOI: 10.1021/acs.chemmater.4c02198
Tyger H. Salters, James Colagiuri, Andre Koch Liston, Josh Leeman, Tanya Berry, Leslie M. Schoop
The solid solution LnSbxTe2–x–δ (Ln = lanthanide) is a family of square-net topological semimetals that exhibit tunable charge density wave (CDW) distortions and band filling dependent on x, offering broad opportunities to examine the interplay of topological electronic states, CDW, and magnetism. While several Ln series have been characterized, gaps in the literature remain, inviting a systematic survey of the remaining composition space that is synthetically accessible. We present our efforts to synthesize LnSbxTe2–x–δ across the remaining lanthanides via chemical vapor transport. Compiling our results with the reported literature, we generate a stability phase diagram across the ranges of Ln and x. We find a stability boundary for intermediate x beyond Tb, while x = 1 and x = 0 can be isolated up to Ho and Dy, respectively. SEM and XRD analyses of unsuccessful reactions indicated the formation of several stable binary phases. The presence of structurally related LnTe3 in samples suggests that stability is limited by the size of Ln, due to increasing compressive strain along the layer stacking axis with decreasing size. Finally, we demonstrate that late Ln can be stabilized in LnSbxTe2–x–δ via substitution into larger Ln members, synthesizing La1–yHoySbxTe2–x–δ as a proof of concept.
{"title":"Synthesis and Stability Phase Diagram of Topological Semimetal Family LnSbxTe2–x–δ","authors":"Tyger H. Salters, James Colagiuri, Andre Koch Liston, Josh Leeman, Tanya Berry, Leslie M. Schoop","doi":"10.1021/acs.chemmater.4c02198","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02198","url":null,"abstract":"The solid solution LnSb<sub><i>x</i></sub>Te<sub>2–<i>x</i>–δ</sub> (Ln = lanthanide) is a family of square-net topological semimetals that exhibit tunable charge density wave (CDW) distortions and band filling dependent on <i>x</i>, offering broad opportunities to examine the interplay of topological electronic states, CDW, and magnetism. While several Ln series have been characterized, gaps in the literature remain, inviting a systematic survey of the remaining composition space that is synthetically accessible. We present our efforts to synthesize LnSb<sub><i>x</i></sub>Te<sub>2–<i>x</i>–δ</sub> across the remaining lanthanides via chemical vapor transport. Compiling our results with the reported literature, we generate a stability phase diagram across the ranges of Ln and <i>x</i>. We find a stability boundary for intermediate <i>x</i> beyond Tb, while <i>x</i> = 1 and <i>x</i> = 0 can be isolated up to Ho and Dy, respectively. SEM and XRD analyses of unsuccessful reactions indicated the formation of several stable binary phases. The presence of structurally related LnTe<sub>3</sub> in samples suggests that stability is limited by the size of Ln, due to increasing compressive strain along the layer stacking axis with decreasing size. Finally, we demonstrate that late Ln can be stabilized in LnSb<sub><i>x</i></sub>Te<sub>2–<i>x</i>–δ</sub> via substitution into larger Ln members, synthesizing La<sub>1–<i>y</i></sub>Ho<sub><i>y</i></sub>Sb<sub><i>x</i></sub>Te<sub>2–<i>x</i>–δ</sub> as a proof of concept.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"12 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142763912","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 : 2024-12-04DOI: 10.1021/acs.chemmater.4c02831
Jian Zhang, Xianzhi Yang, Chen Chen, Yonghua Li, Jin Li, Wei Chen, Yan Cui, Xing’ao Li, Xinbao Zhu
The interface electronic structure of heterogeneous catalysts can be modulated by changing the surface coordination configuration, which is crucial to their catalytic activity. Herein, a surface phosphorus-grafted Ti3C2Tx MXene platform anchored with an MoS2 nanoflake heterojunction electrocatalyst was assembled through a simple phosphorus-hydrothermal method. An interface charge “bridge” has been created by grafting uniform P atoms coordinated with the surface O atoms of Ti3C2Tx (P-Ti3C2Tx), resulting in an interface charge-transfer channel between P-Ti3C2Tx and MoS2. Based on the ultrafast transient absorption spectroscopy, the fastest electron-transfer kinetics from P-Ti3C2Tx to MoS2 (1.7 ps) and the slowest electron–hole recombination speed (28 ps) were obtained over MoS2@P-Ti3C2Tx than those over MoS2@O-Ti3C2Tx and MoS2@OP-Ti3C2Tx. Benefiting from the lower carrier transport activation energy, MoS2@P-Ti3C2Tx exhibited the stirring electrocatalytic activity toward hydrogen evolution in all-pH media, which delivered three low overpotentials of 48.6, 63.2, and 70.5 mV at 10 mA cm–2 toward the hydrogen evolution in alkaline, acid, and neutral media, respectively. Grafting an atomic scale “bridge” to create an electron-transfer channel proposes a new strategy to design an efficient pH-universal hydrogen evolution heterojunction electrocatalyst.
{"title":"Surface Phosphorus Grafting of Ti3C2Tx MXene as an Interface Charge “Bridge” for Efficient Electrocatalytic Hydrogen Evolution in All-pH Media","authors":"Jian Zhang, Xianzhi Yang, Chen Chen, Yonghua Li, Jin Li, Wei Chen, Yan Cui, Xing’ao Li, Xinbao Zhu","doi":"10.1021/acs.chemmater.4c02831","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02831","url":null,"abstract":"The interface electronic structure of heterogeneous catalysts can be modulated by changing the surface coordination configuration, which is crucial to their catalytic activity. Herein, a surface phosphorus-grafted Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> MXene platform anchored with an MoS<sub>2</sub> nanoflake heterojunction electrocatalyst was assembled through a simple phosphorus-hydrothermal method. An interface charge “bridge” has been created by grafting uniform P atoms coordinated with the surface O atoms of Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> (P-Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub>), resulting in an interface charge-transfer channel between P-Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> and MoS<sub>2</sub>. Based on the ultrafast transient absorption spectroscopy, the fastest electron-transfer kinetics from P-Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> to MoS<sub>2</sub> (1.7 ps) and the slowest electron–hole recombination speed (28 ps) were obtained over MoS<sub>2</sub>@P-Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> than those over MoS<sub>2</sub>@O-Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> and MoS<sub>2</sub>@OP-Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub>. Benefiting from the lower carrier transport activation energy, MoS<sub>2</sub>@P-Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> exhibited the stirring electrocatalytic activity toward hydrogen evolution in all-pH media, which delivered three low overpotentials of 48.6, 63.2, and 70.5 mV at 10 mA cm<sup>–2</sup> toward the hydrogen evolution in alkaline, acid, and neutral media, respectively. Grafting an atomic scale “bridge” to create an electron-transfer channel proposes a new strategy to design an efficient pH-universal hydrogen evolution heterojunction electrocatalyst.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"12 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142777286","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 : 2024-12-03DOI: 10.1021/acs.chemmater.4c01892
Ekaterina Bellan, Martin Jakoobi, Vincent Collière, Yannick Coppel, Julien Trébosc, Olivier Lafon, Pierre Lecante, Paul Fleurat-Lessard, Céline Dupont, Jean-Cyrille Hierso, Pierre Fau, Katia Fajerwerg, Lauriane Pautrot-d’Alençon, Thierry Le Mercier, Myrtil L. Kahn
Semiconducting heterostructures are considered promising candidates for meeting specific environmental challenges, such as greener or decarbonated production of energy. However, optimizing the performance of these hybrid systems largely depends on the fine understanding of the mechanisms by which they are formed in relation to their mode of preparation. We report herein the synthesis of nanosized semiconducting heterostructures of ZnS@ZnO shell-core nature; this is from well-controlled preformed ZnO nanoparticles (NPs) modified via anion exchange process using (TMS)2S. The formation of these ZnS@ZnO heterostructures has been investigated in depth, shedding light specifically on the sulfidation mechanism and its dynamics. Our study reveals the dynamic evolution of the nanomaterial in the sulfidation process, evidencing that it is both driven by the initial presence of oxygen vacancies─acting as gateways for sulfur atoms─and also by the action in the medium of (TMS)2S, which as a sulfurizing agent behaves also as an oxygen atom extractor. The structural modification of the preformed monocrystalline ZnO nanomaterial into a polycrystalline ZnS hollow nanostructure occurs via amorphization–crystallization steps, which clearly depends on the amount of (TMS)2S in the reaction. This morphological transition to a hollow structure has been followed by multinuclear NMR spectroscopy (1H, 13C, 17O), and notably oxygen atoms at the interfaces of ZnS@ZnO heterostructures have been identified and quantified. Consistently, our study clearly establishes the link between the preparation mode of the ZnS@ZnO heterostructures and the modification of their optical band gaps as a function of their composition. The variation in optical properties, and the bowing of the band gap, depends on the sulfidation level, and this mode of sulfidation is clarified step-by-step by a DFT computational approach of surface and interface processes that is fully supported by the experimental characterization (XRD, WAXS, EDX line-analysis, HRTEM, STEM-HAADF) of these materials.
{"title":"Understanding Ion-Exchange Processes in the Synthesis of ZnSx@ZnO1–x Heterostructures from Controlled Sulfidation of ZnO Nanocrystals","authors":"Ekaterina Bellan, Martin Jakoobi, Vincent Collière, Yannick Coppel, Julien Trébosc, Olivier Lafon, Pierre Lecante, Paul Fleurat-Lessard, Céline Dupont, Jean-Cyrille Hierso, Pierre Fau, Katia Fajerwerg, Lauriane Pautrot-d’Alençon, Thierry Le Mercier, Myrtil L. Kahn","doi":"10.1021/acs.chemmater.4c01892","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c01892","url":null,"abstract":"Semiconducting heterostructures are considered promising candidates for meeting specific environmental challenges, such as greener or decarbonated production of energy. However, optimizing the performance of these hybrid systems largely depends on the fine understanding of the mechanisms by which they are formed in relation to their mode of preparation. We report herein the synthesis of nanosized semiconducting heterostructures of ZnS@ZnO shell-core nature; this is from well-controlled preformed ZnO nanoparticles (NPs) modified via anion exchange process using (TMS)<sub>2</sub>S. The formation of these ZnS@ZnO heterostructures has been investigated in depth, shedding light specifically on the sulfidation mechanism and its dynamics. Our study reveals the dynamic evolution of the nanomaterial in the sulfidation process, evidencing that it is both driven by the initial presence of oxygen vacancies─acting as gateways for sulfur atoms─and also by the action in the medium of (TMS)<sub>2</sub>S, which as a sulfurizing agent behaves also as an oxygen atom extractor. The structural modification of the preformed monocrystalline ZnO nanomaterial into a polycrystalline ZnS hollow nanostructure occurs via amorphization–crystallization steps, which clearly depends on the amount of (TMS)<sub>2</sub>S in the reaction. This morphological transition to a hollow structure has been followed by multinuclear NMR spectroscopy (<sup>1</sup>H, <sup>13</sup>C, <sup>17</sup>O), and notably oxygen atoms at the interfaces of ZnS@ZnO heterostructures have been identified and quantified. Consistently, our study clearly establishes the link between the preparation mode of the ZnS@ZnO heterostructures and the modification of their optical band gaps as a function of their composition. The variation in optical properties, and the bowing of the band gap, depends on the sulfidation level, and this mode of sulfidation is clarified step-by-step by a DFT computational approach of surface and interface processes that is fully supported by the experimental characterization (XRD, WAXS, EDX line-analysis, HRTEM, STEM-HAADF) of these materials.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"117 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142763907","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 : 2024-12-03DOI: 10.1021/acs.chemmater.4c02146
Alessia Provino, Thomas J. Emge, David Walker, Corey E. Frank, Suguru Yoshida, Venkatraman Gopalan, Mark Croft, Zheng Deng, Changqing Jin, Pietro Manfrinetti, Martha Greenblatt
Two new compounds, Zn2FeSbO6 and Zn2MnSbO6, have been synthesized under high-pressure and high-temperature conditions. The synthesis, single-crystal and powder X-ray diffraction, X-ray absorption near-edge spectroscopy (XANES), optical second harmonic generation (SHG), and magnetic and heat capacity measurements were carried out for both compounds and are described. The lattice parameters are a = 5.17754(6) Å and c = 13.80045(16) Å for Zn2FeSbO6 and a = 5.1889(10) Å and c = 14.0418(3) Å for Zn2MnSbO6. Single-crystal X-ray diffraction analyses indicate that Zn2FeSbO6 consists of a cocrystal of superimposed Ni3TeO6 (NTO) and ordered ilmenite (OIL) components with a ratio of approximately 2:1 and Zn2MnSbO6 contains two nearly identical, but noncrystallographically related, OIL components in a ratio of approximately 6:1. XANES analysis shows Fe3+ and Mn3+ as formal oxidation states for Fe and Mn cations, respectively, for these A2BB′O6 compounds. SHG measurements for Zn2MnSbO6 indicate that it is noncentrosymmetric and confirm the polar R3 (no. 146) space group strongly implied by single-crystal reflection data. The magnetic measurements reveal spin-glass behavior with antiferromagnetic (AFM) interactions in both compounds and a frustration factor (f) being significantly larger for Zn2MnSbO6 (f ≈ 20) compared to Zn2FeSbO6 (f ≈ 7). While Zn2FeSbO6 exhibits AFM ordering at a Néel temperature (TN) of 9 K, Zn2MnSbO6 shows magnetic ordering around 4 K. Additionally, the negative Curie–Weiss temperatures for both compounds corroborate the presence of AFM exchange interactions.
{"title":"Zn2MnSbO6 and Zn2FeSbO6: Two New Polar High-Pressure Ordered Corundum-Type Compounds","authors":"Alessia Provino, Thomas J. Emge, David Walker, Corey E. Frank, Suguru Yoshida, Venkatraman Gopalan, Mark Croft, Zheng Deng, Changqing Jin, Pietro Manfrinetti, Martha Greenblatt","doi":"10.1021/acs.chemmater.4c02146","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02146","url":null,"abstract":"Two new compounds, Zn<sub>2</sub>FeSbO<sub>6</sub> and Zn<sub>2</sub>MnSbO<sub>6</sub>, have been synthesized under high-pressure and high-temperature conditions. The synthesis, single-crystal and powder X-ray diffraction, X-ray absorption near-edge spectroscopy (XANES), optical second harmonic generation (SHG), and magnetic and heat capacity measurements were carried out for both compounds and are described. The lattice parameters are <i>a</i> = 5.17754(6) Å and <i>c</i> = 13.80045(16) Å for Zn<sub>2</sub>FeSbO<sub>6</sub> and <i>a</i> = 5.1889(10) Å and <i>c</i> = 14.0418(3) Å for Zn<sub>2</sub>MnSbO<sub>6</sub>. Single-crystal X-ray diffraction analyses indicate that Zn<sub>2</sub>FeSbO<sub>6</sub> consists of a cocrystal of superimposed Ni<sub>3</sub>TeO<sub>6</sub> (NTO) and ordered ilmenite (OIL) components with a ratio of approximately 2:1 and Zn<sub>2</sub>MnSbO<sub>6</sub> contains two nearly identical, but noncrystallographically related, OIL components in a ratio of approximately 6:1. XANES analysis shows Fe<sup>3+</sup> and Mn<sup>3+</sup> as formal oxidation states for Fe and Mn cations, respectively, for these A<sub>2</sub>BB′O<sub>6</sub> compounds. SHG measurements for Zn<sub>2</sub>MnSbO<sub>6</sub> indicate that it is noncentrosymmetric and confirm the polar <i>R</i>3 (no. 146) space group strongly implied by single-crystal reflection data. The magnetic measurements reveal spin-glass behavior with antiferromagnetic (AFM) interactions in both compounds and a frustration factor (<i>f</i>) being significantly larger for Zn<sub>2</sub>MnSbO<sub>6</sub> (<i>f</i> ≈ 20) compared to Zn<sub>2</sub>FeSbO<sub>6</sub> (<i>f</i> ≈ 7). While Zn<sub>2</sub>FeSbO<sub>6</sub> exhibits AFM ordering at a Néel temperature (<i>T</i><sub>N</sub>) of 9 K, Zn<sub>2</sub>MnSbO<sub>6</sub> shows magnetic ordering around 4 K. Additionally, the negative Curie–Weiss temperatures for both compounds corroborate the presence of AFM exchange interactions.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"13 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142760523","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 : 2024-12-03DOI: 10.1021/acs.chemmater.4c02422
Monika Schied, Hanna Pazniak, Florian Brette, Paolo Lacovig, Michael Paris, Florent Boucher, Silvano Lizzit, Vincent Mauchamp, Rosanna Larciprete
Two-dimensional transition metal carbides or nitrides, so-called MXenes, hold the prospect of a proactive emergence as innovative catalysts and device components owing to the specific qualities gained from the chemical species that functionalize the layers. Tuning the nature and the number of the surface terminations becomes the key factor for the effective use of MXenes in technology. This study explores the capability of H atoms to modify the surface composition of Ti3C2Tx flakes. While exposing the sample at room temperature to H atoms, the change of its surface chemical state is followed by synchrotron radiation X-ray photoelectron spectroscopy. It turns out that halogen terminations are progressively and substantially removed. In parallel, the O terminations are partially converted into OH groups, the O/OH ratio being possibly controlled by the OH–OH repulsion. The dramatic surface composition change leaves the valence state of the Ti atoms almost unchanged. Density functional theory simulations of the valence band spectra for different Ti3C2Tx model systems identify all spectral features and model the change of the electronic properties around the Fermi level. Heating the hydrogenated sample to 400 K removes the OH groups, leaving the MXene surface deprived of most of the pristine terminations, thus giving way to new, application-oriented functionalization.
{"title":"Reactivity of Ti3C2Tx MXene with Atomic Hydrogen: Tuning of Surface Terminations by Halogen Removal and Reversible O to OH Conversion","authors":"Monika Schied, Hanna Pazniak, Florian Brette, Paolo Lacovig, Michael Paris, Florent Boucher, Silvano Lizzit, Vincent Mauchamp, Rosanna Larciprete","doi":"10.1021/acs.chemmater.4c02422","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02422","url":null,"abstract":"Two-dimensional transition metal carbides or nitrides, so-called MXenes, hold the prospect of a proactive emergence as innovative catalysts and device components owing to the specific qualities gained from the chemical species that functionalize the layers. Tuning the nature and the number of the surface terminations becomes the key factor for the effective use of MXenes in technology. This study explores the capability of H atoms to modify the surface composition of Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> flakes. While exposing the sample at room temperature to H atoms, the change of its surface chemical state is followed by synchrotron radiation X-ray photoelectron spectroscopy. It turns out that halogen terminations are progressively and substantially removed. In parallel, the O terminations are partially converted into OH groups, the O/OH ratio being possibly controlled by the OH–OH repulsion. The dramatic surface composition change leaves the valence state of the Ti atoms almost unchanged. Density functional theory simulations of the valence band spectra for different Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> model systems identify all spectral features and model the change of the electronic properties around the Fermi level. Heating the hydrogenated sample to 400 K removes the OH groups, leaving the MXene surface deprived of most of the pristine terminations, thus giving way to new, application-oriented functionalization.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"74 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142760521","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 : 2024-12-03DOI: 10.1021/acs.chemmater.4c02592
Tongxin Zhou, Arulmonic Britto Seethalakshmi, Divakar Arumugam, Lihua Zhang, A. M. Milinda Abeykoon, Gihan Kwon, Daniel Olds, Xiaowei Teng
Vanadium-based oxides are intriguing electrode materials in aqueous electrochemical systems owing to their low cost and high theoretical capacity for alkali storage, especially lithium (Li) ions. However, a sequence of phase transformations and irreversible structure distortion upon Li-ion intercalation causes structural instability and has been a lingering problem for vanadium oxide electrodes. Here, we investigate lithium vanadate (Li–V3O8) for aqueous Li-ion intercalation and deintercalation processes. Unlike its crystalline V2O5 polymorph, Li–V3O8 retains monophasic lithiation, which is attributed to its disordered crystalline nature and large interplanar distance. Importantly, we show a unique and reversible sequence of disorder-to-order structural transition induced by the extent of lithiation, which indicates sequential interlayer and intralayer lithiation process, and vice versa in delithiation process, supported by electrokinetic analysis, in situ X-ray diffraction (XRD), and Debye scattering simulations. The absence of distortive phase transitions and multilithiation pathways facilitates Li-ion diffusion across the vanadate electrode materials to improve storage capacity. This work opens a new dimension for vanadium-based disordered oxides, accelerating the development of low-cost, aqueous electrochemical systems.
{"title":"Reversible Disorder-to-Order Transition Induced by Aqueous Lithiation in Vanadate Electrode Materials","authors":"Tongxin Zhou, Arulmonic Britto Seethalakshmi, Divakar Arumugam, Lihua Zhang, A. M. Milinda Abeykoon, Gihan Kwon, Daniel Olds, Xiaowei Teng","doi":"10.1021/acs.chemmater.4c02592","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02592","url":null,"abstract":"Vanadium-based oxides are intriguing electrode materials in aqueous electrochemical systems owing to their low cost and high theoretical capacity for alkali storage, especially lithium (Li) ions. However, a sequence of phase transformations and irreversible structure distortion upon Li-ion intercalation causes structural instability and has been a lingering problem for vanadium oxide electrodes. Here, we investigate lithium vanadate (Li–V<sub>3</sub>O<sub>8</sub>) for aqueous Li-ion intercalation and deintercalation processes. Unlike its crystalline V<sub>2</sub>O<sub>5</sub> polymorph, Li–V<sub>3</sub>O<sub>8</sub> retains monophasic lithiation, which is attributed to its disordered crystalline nature and large interplanar distance. Importantly, we show a unique and reversible sequence of disorder-to-order structural transition induced by the extent of lithiation, which indicates sequential interlayer and intralayer lithiation process, and <i>vice versa</i> in delithiation process, supported by electrokinetic analysis, <i>in situ</i> X-ray diffraction (XRD), and Debye scattering simulations. The absence of distortive phase transitions and multilithiation pathways facilitates Li-ion diffusion across the vanadate electrode materials to improve storage capacity. This work opens a new dimension for vanadium-based disordered oxides, accelerating the development of low-cost, aqueous electrochemical systems.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"13 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142760531","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 : 2024-12-03DOI: 10.1021/acs.chemmater.4c02887
Jiarong Lv, Gangji Yi, Xuan Zou, Hongkun Liu, Xiangyu Han, Ling Huang, Hongmei Zeng, Zhien Lin, Guohong Zou
Birefringent crystals with significant optical anisotropy have played a pivotal role in laser technology and scientific research by modulating and controlling light polarization. In this study, we have successfully synthesized three new birefringent materials with mixed-valence antimony, namely, KSb3O6, RbSb3O6, and α-Sb2O4, through the introduction of Sb3+ with stereochemically active lone pairs (SCALP) to the total oxygen system using a high-temperature solution method. To the best of our knowledge, K/RbSb3O6 represents the first alkali metal mixed-valence Sb-based oxide. Interestingly, despite their similar sandwich structure, these materials exhibit vastly different levels of birefringence (almost 10 times difference). It is worth noting that α-Sb2O4 demonstrates the largest experimental birefringence (0.201 at 546 nm) among non-π-conjugated Sb-based oxides to date, which can be attributed to the synergistic effect of SCALP group distortion and arrangement. These findings hold valuable implications for guiding future efforts in designing and synthesizing large birefringent materials.
{"title":"Birefringence Disparity Induced by Synergistic Effects of Stereochemically Active Lone Pairs","authors":"Jiarong Lv, Gangji Yi, Xuan Zou, Hongkun Liu, Xiangyu Han, Ling Huang, Hongmei Zeng, Zhien Lin, Guohong Zou","doi":"10.1021/acs.chemmater.4c02887","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02887","url":null,"abstract":"Birefringent crystals with significant optical anisotropy have played a pivotal role in laser technology and scientific research by modulating and controlling light polarization. In this study, we have successfully synthesized three new birefringent materials with mixed-valence antimony, namely, KSb<sub>3</sub>O<sub>6</sub>, RbSb<sub>3</sub>O<sub>6</sub>, and α-Sb<sub>2</sub>O<sub>4</sub>, through the introduction of Sb<sup>3+</sup> with stereochemically active lone pairs (SCALP) to the total oxygen system using a high-temperature solution method. To the best of our knowledge, K/RbSb<sub>3</sub>O<sub>6</sub> represents the first alkali metal mixed-valence Sb-based oxide. Interestingly, despite their similar sandwich structure, these materials exhibit vastly different levels of birefringence (almost 10 times difference). It is worth noting that α-Sb<sub>2</sub>O<sub>4</sub> demonstrates the largest experimental birefringence (0.201 at 546 nm) among non-π-conjugated Sb-based oxides to date, which can be attributed to the synergistic effect of SCALP group distortion and arrangement. These findings hold valuable implications for guiding future efforts in designing and synthesizing large birefringent materials.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"215 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142763908","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}
Oxychalcogenides have become notable contenders for infrared nonlinear optical (IR NLO) applications because of their diverse heteroanionic functional motifs. However, while the main group elements are well-explored for these motifs, transition elements have been less studied and lack high-performance materials. To address this gap, we investigated a series of noncentrosymmetric [Ba4(Ba6S)][(VOxS4–x)6] (space group: P63), the first V-based salt-inclusion oxychalcogenides demonstrating phase-matched IR-NLO properties. We achieved this by cation–anion module cosubstitution in the centrosymmetric structure of [Ba4(Ba6Cl2)][(VO4)6] (space group: P63/m). The novel [Ba4(Ba6S)][(VOxS4–x)6] features isolated heteroanionic [VOxS4–x]3– units, charge-balanced Ba2+ cations, and a one-dimensional cationic chain of [Ba6S]10+ octahedral units. Moreover, [Ba4(Ba6S)][(VO3S)6] exhibits notable properties including a high second-harmonic-generation intensity (1.33 × AgGaS2@2900 nm), a substantial laser-induced damage threshold (7.65 × AgGaS2), a broad IR cutoff edge (up to 11.2 μm), and significant birefringence for phase matching (Δn = 0.073@2900 nm). Structural analysis and DFT calculations demonstrate that the configuration of the [VO3S]3– units enhances NLO properties and increases structural anisotropy. Our findings suggest that V-based salt-inclusion oxychalcogenides are a promising class for IR-NLO applications and highlight cation–anion module cosubstitution as an effective approach for creating high-performance heteroanionic NLO crystals.
{"title":"Balanced IR Nonlinear Optical Performance Achieved by Cation–Anion Module Cosubstitution in V-Based Salt-Inclusion Oxychalcogenides","authors":"Mao-Yin Ran, Sheng-Hua Zhou, Bing-Xuan Li, Xin-Tao Wu, Hua Lin, Qi-Long Zhu","doi":"10.1021/acs.chemmater.4c02779","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02779","url":null,"abstract":"Oxychalcogenides have become notable contenders for infrared nonlinear optical (IR NLO) applications because of their diverse heteroanionic functional motifs. However, while the main group elements are well-explored for these motifs, transition elements have been less studied and lack high-performance materials. To address this gap, we investigated a series of noncentrosymmetric [Ba<sub>4</sub>(Ba<sub>6</sub>S)][(VO<sub><i>x</i></sub>S<sub>4–<i>x</i></sub>)<sub>6</sub>] (space group: <i>P</i>6<sub>3</sub>), the first V-based salt-inclusion oxychalcogenides demonstrating phase-matched IR-NLO properties. We achieved this by cation–anion module cosubstitution in the centrosymmetric structure of [Ba<sub>4</sub>(Ba<sub>6</sub>Cl<sub>2</sub>)][(VO<sub>4</sub>)<sub>6</sub>] (space group: <i>P</i>6<sub>3</sub>/<i>m</i>). The novel [Ba<sub>4</sub>(Ba<sub>6</sub>S)][(VO<sub><i>x</i></sub>S<sub>4–<i>x</i></sub>)<sub>6</sub>] features isolated heteroanionic [VO<sub><i>x</i></sub>S<sub>4–<i>x</i></sub>]<sup>3–</sup> units, charge-balanced Ba<sup>2+</sup> cations, and a one-dimensional cationic chain of [Ba<sub>6</sub>S]<sup>10+</sup> octahedral units. Moreover, [Ba<sub>4</sub>(Ba<sub>6</sub>S)][(VO<sub>3</sub>S)<sub>6</sub>] exhibits notable properties including a high second-harmonic-generation intensity (1.33 × AgGaS<sub>2</sub>@2900 nm), a substantial laser-induced damage threshold (7.65 × AgGaS<sub>2</sub>), a broad IR cutoff edge (up to 11.2 μm), and significant birefringence for phase matching (Δ<i>n</i> = 0.073@2900 nm). Structural analysis and DFT calculations demonstrate that the configuration of the [VO<sub>3</sub>S]<sup>3–</sup> units enhances NLO properties and increases structural anisotropy. Our findings suggest that V-based salt-inclusion oxychalcogenides are a promising class for IR-NLO applications and highlight cation–anion module cosubstitution as an effective approach for creating high-performance heteroanionic NLO crystals.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"18 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142760522","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 : 2024-12-03DOI: 10.1021/acs.chemmater.4c02109
Noa Azaria, Danielle Schweke, Lee Shelly, Shmuel Hayun
Ceria (CeO2) and doped ceria are well known for their catalytic surfaces that are active in various oxidation/reduction processes such as hydrogen production through thermochemical water splitting and three-way catalyst in combustion engines. Doping ceria with trivalent cations is expected to increase the concentration of oxygen vacancies due to charge compensation, but its effect on oxygen mobility or adsorption is not straightforward and depends on the specific trivalent element considered. In this study, we explore the effect of La addition on the bulk and surface properties of ceria by combining bulk (X-ray diffraction, thermogravimetry analysis, differential scanning calorimetry, and temperature-programmed desorption) and surface-sensitive techniques (X-ray photoelectron spectroscopy and water adsorption calorimetry). Three nanosized compositions of ceria doped with La were synthesized (at 5, 10, and 15% La3+) and thoroughly characterized. Compared with undoped ceria, the solid solutions obtained exhibited enhanced thermal stability. The solid solutions preserved their fluorite structure up to 1200 °C and exhibited a significantly reduced coarsening compared to pure ceria. The enhanced stability is attributed to the segregation of La to the surface. Doping of ceria with La led to an increase in the oxygen storage capacity, with the effect increasing with the increasing concentration of La. This increase was attributed to increased oxygen mobility with increasing La concentration. The addition of a small concentration of La (5%) leads to a significant increase in the amount of water adsorbed compared to pure ceria. Notably, water adsorption led to an enrichment of La on the surface, most pronounced for the highest La content, probably as the result of La diffusion from the subsurface to the surface. The heat of adsorption isotherms exhibits an unusual behavior, pointing to the need for further theoretical work.
{"title":"Effect of La Addition to Ceria on the Oxygen Storage Capacity and the Energetics of Water Adsorption","authors":"Noa Azaria, Danielle Schweke, Lee Shelly, Shmuel Hayun","doi":"10.1021/acs.chemmater.4c02109","DOIUrl":"https://doi.org/10.1021/acs.chemmater.4c02109","url":null,"abstract":"Ceria (CeO<sub>2</sub>) and doped ceria are well known for their catalytic surfaces that are active in various oxidation/reduction processes such as hydrogen production through thermochemical water splitting and three-way catalyst in combustion engines. Doping ceria with trivalent cations is expected to increase the concentration of oxygen vacancies due to charge compensation, but its effect on oxygen mobility or adsorption is not straightforward and depends on the specific trivalent element considered. In this study, we explore the effect of La addition on the bulk and surface properties of ceria by combining bulk (X-ray diffraction, thermogravimetry analysis, differential scanning calorimetry, and temperature-programmed desorption) and surface-sensitive techniques (X-ray photoelectron spectroscopy and water adsorption calorimetry). Three nanosized compositions of ceria doped with La were synthesized (at 5, 10, and 15% La<sup>3+</sup>) and thoroughly characterized. Compared with undoped ceria, the solid solutions obtained exhibited enhanced thermal stability. The solid solutions preserved their fluorite structure up to 1200 °C and exhibited a significantly reduced coarsening compared to pure ceria. The enhanced stability is attributed to the segregation of La to the surface. Doping of ceria with La led to an increase in the oxygen storage capacity, with the effect increasing with the increasing concentration of La. This increase was attributed to increased oxygen mobility with increasing La concentration. The addition of a small concentration of La (5%) leads to a significant increase in the amount of water adsorbed compared to pure ceria. Notably, water adsorption led to an enrichment of La on the surface, most pronounced for the highest La content, probably as the result of La diffusion from the subsurface to the surface. The heat of adsorption isotherms exhibits an unusual behavior, pointing to the need for further theoretical work.","PeriodicalId":33,"journal":{"name":"Chemistry of Materials","volume":"262 1","pages":""},"PeriodicalIF":8.6,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142763911","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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