Pub Date : 2024-11-18DOI: 10.1021/acs.jpcc.4c04167
F. Elfatouaki, R. Takassa, M. Alla, O. Farkad, Abdelkarim EL Mouncharih, S. Hassine, S. Giusepponi, E. A. Ibnouelghazi, A. Outzourhit, D. Abouelaoualim
Ruddlesden–Popper (RP) perovskite materials are gaining traction in optoelectronic applications due to their unique structure and adjustable properties. This study investigates the potential of RP (2D) Cs2GeI2Br2 and (3D) CsGeI2Br absorbers in enhancing perovskite solar cell (PSC) performance. Through rigorous analysis, we find that integrating RP phases improves charge transport and reduces defects, leading to superior device performance. The results showed a direct bandgap (1.45 eV for 2D), high optical absorption (above 50 × 104 cm–1 for 3D), low reflectivity, and energy loss, indicating solar cell suitability. The calculated effective mass values (me*, mh*) (0.245, 0.423 eV) for Cs2GeI2Br2 closely resemble those reported for Cs2PbI2Br2 and Cs2PbI2Cl2, indicating similar charge carrier behavior in these materials. Our research provides valuable insights for optimizing PSCs with alternative structures. Additionally, simulations explore various hole transport layers and temperature effects on key electrical parameters under standard AM 1.5 G solar radiation using the SCAPS-1D software, achieving a maximum efficiency of approximately 29.59% for the PSC prototype at an ambient temperature of 25 °C.
Ruddlesden-Popper (RP) 包晶材料因其独特的结构和可调节的特性，在光电应用领域正日益受到重视。本研究探讨了 RP (2D) Cs2GeI2Br2 和 (3D) CsGeI2Br 吸收体在提高包晶体太阳能电池 (PSC) 性能方面的潜力。通过严谨的分析，我们发现集成 RP 相可以改善电荷传输并减少缺陷，从而提高器件性能。结果显示，直接带隙（2D 为 1.45 eV）、高光吸收（3D 为 50 × 104 cm-1 以上）、低反射率和能量损耗表明太阳能电池的适用性。计算得出的 Cs2GeI2Br2 有效质量值 (me*, mh*) (0.245, 0.423 eV) 与 Cs2PbI2Br2 和 Cs2PbI2Cl2 的有效质量值非常接近，表明这些材料中的电荷载流子行为相似。我们的研究为优化具有替代结构的 PSC 提供了宝贵的见解。此外，在标准 AM 1.5 G 太阳辐射条件下，使用 SCAPS-1D 软件模拟探索了各种空穴传输层和温度对关键电气参数的影响，在环境温度为 25 °C 时，PSC 原型的最高效率约为 29.59%。
{"title":"Enhancing Perovskite Solar Cells Performance Through Investigation of Ruddlesden–Popper (2D) Cs2GeI2Br2 and (3D) CsGeI2Br Absorbers","authors":"F. Elfatouaki, R. Takassa, M. Alla, O. Farkad, Abdelkarim EL Mouncharih, S. Hassine, S. Giusepponi, E. A. Ibnouelghazi, A. Outzourhit, D. Abouelaoualim","doi":"10.1021/acs.jpcc.4c04167","DOIUrl":"https://doi.org/10.1021/acs.jpcc.4c04167","url":null,"abstract":"Ruddlesden–Popper (RP) perovskite materials are gaining traction in optoelectronic applications due to their unique structure and adjustable properties. This study investigates the potential of RP (2D) Cs<sub>2</sub>GeI<sub>2</sub>Br<sub>2</sub> and (3D) CsGeI<sub>2</sub>Br absorbers in enhancing perovskite solar cell (PSC) performance. Through rigorous analysis, we find that integrating RP phases improves charge transport and reduces defects, leading to superior device performance. The results showed a direct bandgap (1.45 eV for 2D), high optical absorption (above 50 × 10<sup>4</sup> cm<sup>–1</sup> for 3D), low reflectivity, and energy loss, indicating solar cell suitability. The calculated effective mass values (<i>m</i><sub>e</sub><sup>*</sup>, <i>m</i><sub>h</sub><sup>*</sup>) (0.245, 0.423 eV) for Cs<sub>2</sub>GeI<sub>2</sub>Br<sub>2</sub> closely resemble those reported for Cs<sub>2</sub>PbI<sub>2</sub>Br<sub>2</sub> and Cs<sub>2</sub>PbI<sub>2</sub>Cl<sub>2</sub>, indicating similar charge carrier behavior in these materials. Our research provides valuable insights for optimizing PSCs with alternative structures. Additionally, simulations explore various hole transport layers and temperature effects on key electrical parameters under standard AM 1.5 G solar radiation using the SCAPS-1D software, achieving a maximum efficiency of approximately 29.59% for the PSC prototype at an ambient temperature of 25 °C.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"22 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142671059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-18DOI: 10.1021/acs.jpcc.4c04821
José D. Gouveia, José R. B. Gomes
In this study, we employed density functional theory calculations to investigate the adsorption behavior of α and β isomers of d-glucopyranose, d-galactopyranose, d-fructopyranose, and d-mannopyranose on the Ti2CO2 MXene surface, in order to understand the potential of this material for sensing sugars. The adsorption process was found to occur via strong noncovalent interactions, primarily through hydrogen bonding and with the hexoses oriented parallel to the surface. The calculated adsorption energies vary between −0.78 (α-d-fructopyranose) and −1.00 eV (β-d-glucopyranose). Importantly, while the charge transfer was found to be negligible, the work function of the material was found to change by up to 0.3 eV in the case of the compound that adsorbs most strongly, β-d-glucopyranose, while less important changes were found for the other studied hexoses. We also explored the influence of defects in the MXene structure on the adsorption of β-d-glucopyranose and observed that oxygen or titanium vacancies enhance the adsorption strength. These findings indicate that the Ti2CO2 MXene is a promising candidate for selective glucopyranose sensing, which can be interesting for glucose detection applications.
{"title":"Adsorption of Hexoses on the Ti2CO2 MXene","authors":"José D. Gouveia, José R. B. Gomes","doi":"10.1021/acs.jpcc.4c04821","DOIUrl":"https://doi.org/10.1021/acs.jpcc.4c04821","url":null,"abstract":"In this study, we employed density functional theory calculations to investigate the adsorption behavior of α and β isomers of <span>d</span>-glucopyranose, <span>d</span>-galactopyranose, <span>d</span>-fructopyranose, and <span>d</span>-mannopyranose on the Ti<sub>2</sub>CO<sub>2</sub> MXene surface, in order to understand the potential of this material for sensing sugars. The adsorption process was found to occur via strong noncovalent interactions, primarily through hydrogen bonding and with the hexoses oriented parallel to the surface. The calculated adsorption energies vary between −0.78 (α-<span>d</span>-fructopyranose) and −1.00 eV (β-<span>d</span>-glucopyranose). Importantly, while the charge transfer was found to be negligible, the work function of the material was found to change by up to 0.3 eV in the case of the compound that adsorbs most strongly, β-<span>d</span>-glucopyranose, while less important changes were found for the other studied hexoses. We also explored the influence of defects in the MXene structure on the adsorption of β-<span>d</span>-glucopyranose and observed that oxygen or titanium vacancies enhance the adsorption strength. These findings indicate that the Ti<sub>2</sub>CO<sub>2</sub> MXene is a promising candidate for selective glucopyranose sensing, which can be interesting for glucose detection applications.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"99 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142671058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
CsPbBr3 perovskite quantum dots (PQDs) are promising candidates for scintillator materials due to their tunable emission wavelength, high light yield, high atomic number, and low cost. However, their poor environmental stability hinders further practical applications. Herein, CsPbBr3 PQD thin film scintillators are encapsulated with selected PMMA, PS, and ER with different thicknesses using the spin-coating method. Photoluminescence spectroscopy is employed to evaluate the light output affected by environmental stability. The results indicated that the PS film outperforms the other two encapsulants in the thermal stability tests at 100 °C and humidity stability tests at relative humidity levels of 95–100%. In particular, the thick PS film, measuring 34.49 μm, demonstrates excellent environmental stability, while the thicknesses of the films ranging from 1.44 to 34.5 μm do not influence the light output of the CsPbBr3 PQD thin-film scintillators, a finding that is corroborated by simulations. This work has significant implications for the practical application of all-inorganic perovskite scintillators in ionizing radiation detection.
{"title":"The Environmental Stability of CsPbBr3 PQD Thin-Film Scintillators with Encapsulants","authors":"Xiaogang Wang, Renjie Chen, Junliang Zhang, Chenxi Han, Yanling Guo, Ximeng Chen, Lin Chen","doi":"10.1021/acs.jpcc.4c06368","DOIUrl":"https://doi.org/10.1021/acs.jpcc.4c06368","url":null,"abstract":"CsPbBr<sub>3</sub> perovskite quantum dots (PQDs) are promising candidates for scintillator materials due to their tunable emission wavelength, high light yield, high atomic number, and low cost. However, their poor environmental stability hinders further practical applications. Herein, CsPbBr<sub>3</sub> PQD thin film scintillators are encapsulated with selected PMMA, PS, and ER with different thicknesses using the spin-coating method. Photoluminescence spectroscopy is employed to evaluate the light output affected by environmental stability. The results indicated that the PS film outperforms the other two encapsulants in the thermal stability tests at 100 °C and humidity stability tests at relative humidity levels of 95–100%. In particular, the thick PS film, measuring 34.49 μm, demonstrates excellent environmental stability, while the thicknesses of the films ranging from 1.44 to 34.5 μm do not influence the light output of the CsPbBr<sub>3</sub> PQD thin-film scintillators, a finding that is corroborated by simulations. This work has significant implications for the practical application of all-inorganic perovskite scintillators in ionizing radiation detection.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"35 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-18DOI: 10.1021/acs.jpcc.4c07016
Arianna Massaro, Francesca Fasulo, Ana B. Muñoz-García, Michele Pavone
Structural and dynamic properties of the poly(ethylene oxide)/anatase interface (i.e., PEO/TiO2) are explored via metadynamics simulations and density functional tight binding. 1-ns trajectories are reconstructed upon two different structure-related collective variables: interfacial Tisurf–OPEO distances and polymer chain torsion angles. The conformational freedom of PEO is significantly influenced by multiple favorable interactions with unsaturated Ti sites on the anatase surface. From these trajectories, several equilibrium structures extracted from the free-energy surface are analyzed using electronic structure calculations within density functional theory: the titania work function results in being largely influenced by the dynamically resolved structuring of PEO on the anatase surface. Besides the intrinsic valuable insights into the technologically relevant PEO/TiO2 interface, our findings provide the first innovative example of an affordable yet reliable computational protocol to describe a heterogeneous interface and predict the effects of molecular dynamics on relevant physicochemical properties.
{"title":"Elucidating Structural and Electronic Features of PEO/(101)-TiO2 Anatase Interfaces through First-Principles Metadynamics Simulations","authors":"Arianna Massaro, Francesca Fasulo, Ana B. Muñoz-García, Michele Pavone","doi":"10.1021/acs.jpcc.4c07016","DOIUrl":"https://doi.org/10.1021/acs.jpcc.4c07016","url":null,"abstract":"Structural and dynamic properties of the poly(ethylene oxide)/anatase interface (<i>i.e.</i>, PEO/TiO<sub>2</sub>) are explored <i>via</i> metadynamics simulations and density functional tight binding. 1-ns trajectories are reconstructed upon two different structure-related collective variables: interfacial Ti<sub>surf</sub>–O<sub>PEO</sub> distances and polymer chain torsion angles. The conformational freedom of PEO is significantly influenced by multiple favorable interactions with unsaturated Ti sites on the anatase surface. From these trajectories, several equilibrium structures extracted from the free-energy surface are analyzed using electronic structure calculations within density functional theory: the titania work function results in being largely influenced by the dynamically resolved structuring of PEO on the anatase surface. Besides the intrinsic valuable insights into the technologically relevant PEO/TiO<sub>2</sub> interface, our findings provide the first innovative example of an affordable yet reliable computational protocol to describe a heterogeneous interface and predict the effects of molecular dynamics on relevant physicochemical properties.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"249 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-18DOI: 10.1021/acs.jpcc.4c06826
Cooper Tezak, Jacob Clary, Sophie Gerits, Joshua Quinton, Benjamin Rich, Nicholas Singstock, Abdulaziz Alherz, Taylor Aubry, Struan Clark, Rachel Hurst, Mauro Del Ben, Christopher Sutton, Ravishankar Sundararaman, Charles Musgrave, Derek Vigil-Fowler
We present BEAST DB, an open-source database comprised of ab initio electrochemical data computed using grand-canonical density functional theory in implicit solvent at consistent calculation parameters. The database contains over 20,000 surface calculations and covers a broad set of heterogeneous catalyst materials and electrochemical reactions. Calculations were performed at self-consistent fixed potential as well as constant charge to facilitate comparisons to the computational hydrogen electrode. This article presents common use cases of the database to rationalize trends in catalyst activity, screen catalyst material spaces, understand elementary mechanistic steps, analyze the electronic structure, and train machine learning models to predict higher fidelity properties. Users can interact graphically with the database by querying for individual calculations to gain a granular understanding of reaction steps or by querying for an entire reaction pathway on a given material using an interactive reaction pathway tool. BEAST DB will be periodically updated, with planned future updates to include advanced electronic structure data, surface speciation studies, and greater reaction coverage.
我们介绍的 BEAST DB 是一个开源数据库，由在隐式溶剂中使用大规范密度泛函理论以一致的计算参数计算的 ab initio 电化学数据组成。该数据库包含 20,000 多项表面计算，涵盖了大量异质催化剂材料和电化学反应。计算是在自洽的固定电位和恒定电荷条件下进行的，以便于与计算氢电极进行比较。本文介绍了该数据库的常见使用案例，以合理解释催化剂活性趋势、筛选催化剂材料空间、了解基本机械步骤、分析电子结构以及训练机器学习模型以预测更高保真特性。用户可以通过查询单个计算结果与数据库进行图形交互，以获得对反应步骤的详细了解，或使用交互式反应途径工具查询特定材料的整个反应途径。BEAST DB 将定期更新，未来计划更新的内容包括高级电子结构数据、表面形态研究和更大的反应范围。
{"title":"BEAST DB: Grand-Canonical Database of Electrocatalyst Properties","authors":"Cooper Tezak, Jacob Clary, Sophie Gerits, Joshua Quinton, Benjamin Rich, Nicholas Singstock, Abdulaziz Alherz, Taylor Aubry, Struan Clark, Rachel Hurst, Mauro Del Ben, Christopher Sutton, Ravishankar Sundararaman, Charles Musgrave, Derek Vigil-Fowler","doi":"10.1021/acs.jpcc.4c06826","DOIUrl":"https://doi.org/10.1021/acs.jpcc.4c06826","url":null,"abstract":"We present BEAST DB, an open-source database comprised of ab initio electrochemical data computed using grand-canonical density functional theory in implicit solvent at consistent calculation parameters. The database contains over 20,000 surface calculations and covers a broad set of heterogeneous catalyst materials and electrochemical reactions. Calculations were performed at self-consistent fixed potential as well as constant charge to facilitate comparisons to the computational hydrogen electrode. This article presents common use cases of the database to rationalize trends in catalyst activity, screen catalyst material spaces, understand elementary mechanistic steps, analyze the electronic structure, and train machine learning models to predict higher fidelity properties. Users can interact graphically with the database by querying for individual calculations to gain a granular understanding of reaction steps or by querying for an entire reaction pathway on a given material using an interactive reaction pathway tool. BEAST DB will be periodically updated, with planned future updates to include advanced electronic structure data, surface speciation studies, and greater reaction coverage.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"32 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-18DOI: 10.1021/acs.jpcc.4c05979
Xue Yan, Kaiyun Chen, Gang Kevin Li, Christian Brandl, Jefferson Zhe Liu
Two-dimensional (2D) van der Waals (vdW) materials have emerged as vital components in various technological fields. Ion intercalation into vdW materials is a versatile technique for material exfoliation, property induction, and stacking-order manipulation. However, the role of the substrate and its consequential impact on ion intercalation thermodynamics in vdW materials are yet to be well understood. In this work, employing density functional theory (DFT) calculations, we investigate the interplay between the SiC substrate and Li+ ion intercalation in the strained bilayer graphene grown on the SiC (0001) substrate. Our analysis covers five stacking orders (AA, AB, BA, SP, and IM stackings), revealing that the SiC substrate enhances the thermostability of Li+ ion intercalation. This enhancement is attributed to the special sp3-hybrid carbon atoms in the bottom graphene layer. We observed that the SiC substrate promotes selective intercalation with a stacking preference, favoring AA stacking over the other four stackings. Surprisingly, the SiC substrate not only disrupts the crystal symmetry within bilayer graphene, leading to distinctive intercalation behaviors in AB and BA stackings ─absent in free-standing bilayer graphene─but also modulates the Fermi level shift downward by inducing p-type doping to facilitate Li+ ion intercalation. Our study offers a comprehensive understanding of the intricate relationship between substrates and ion intercalation in layered materials, thereby paving the way for tailored applications of layered vdW materials with substrates through ion intercalation.
二维范德华（vdW）材料已成为各个技术领域的重要组成部分。离子插层到 vdW 材料中是一种多功能技术，可用于材料剥离、属性诱导和堆叠阶操作。然而，基底的作用及其对 vdW 材料中离子插层热力学的影响仍有待深入了解。在这项工作中，我们利用密度泛函理论（DFT）计算，研究了在碳化硅（0001）基底上生长的应变双层石墨烯中，碳化硅基底与 Li+ 离子插层之间的相互作用。我们的分析涵盖了五种堆积阶（AA、AB、BA、SP 和 IM 堆积），结果表明，SiC 衬底增强了 Li+ 离子插层的耐热性。这种增强归因于底部石墨烯层中特殊的 sp3 杂化碳原子。我们观察到，SiC 衬底促进了具有堆叠偏好的选择性插层，AA 堆叠比其他四种堆叠更受青睐。令人惊讶的是，SiC 衬底不仅破坏了双层石墨烯内部的晶体对称性，导致 AB 和 BA 堆叠出现独特的插层行为--这在独立双层石墨烯中是不存在的--而且还通过诱导 p 型掺杂来调节费米级下移，从而促进 Li+ 离子的插层。我们的研究全面揭示了层状材料中基底与离子插层之间错综复杂的关系，从而为层状 vdW 材料通过离子插层与基底的定制应用铺平了道路。
{"title":"SiC Substrate-Enabled Modulation of Li+ Ion Intercalation Thermostability in Strained Bilayer Graphene","authors":"Xue Yan, Kaiyun Chen, Gang Kevin Li, Christian Brandl, Jefferson Zhe Liu","doi":"10.1021/acs.jpcc.4c05979","DOIUrl":"https://doi.org/10.1021/acs.jpcc.4c05979","url":null,"abstract":"Two-dimensional (2D) van der Waals (vdW) materials have emerged as vital components in various technological fields. Ion intercalation into vdW materials is a versatile technique for material exfoliation, property induction, and stacking-order manipulation. However, the role of the substrate and its consequential impact on ion intercalation thermodynamics in vdW materials are yet to be well understood. In this work, employing density functional theory (DFT) calculations, we investigate the interplay between the SiC substrate and Li<sup>+</sup> ion intercalation in the strained bilayer graphene grown on the SiC (0001) substrate. Our analysis covers five stacking orders (AA, AB, BA, SP, and IM stackings), revealing that the SiC substrate enhances the thermostability of Li<sup>+</sup> ion intercalation. This enhancement is attributed to the special sp<sup>3</sup>-hybrid carbon atoms in the bottom graphene layer. We observed that the SiC substrate promotes selective intercalation with a stacking preference, favoring AA stacking over the other four stackings. Surprisingly, the SiC substrate not only disrupts the crystal symmetry within bilayer graphene, leading to distinctive intercalation behaviors in AB and BA stackings ─absent in free-standing bilayer graphene─but also modulates the Fermi level shift downward by inducing p-type doping to facilitate Li<sup>+</sup> ion intercalation. Our study offers a comprehensive understanding of the intricate relationship between substrates and ion intercalation in layered materials, thereby paving the way for tailored applications of layered vdW materials with substrates through ion intercalation.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"13 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Developing a highly sensitive and accurate method to discriminate between amino acids and peptides is vital for establishing future healthcare testing technologies, such as liquid biopsy. This study proposes a highly sensitive technique based on surface-enhanced Raman scattering (SERS), which combines chemically linking an analyte with gold nanoparticles and aggregating them to produce hotspots. Furthermore, by combining rapid SERS imaging with slit-scanning Raman microscopy and deep learning based on a convolutional neural network, 20 proteinogenic amino acids were successfully detected and distinguished with accuracies exceeding 95%. Also, out of 39 types of dipeptides that have Phe at either the amino terminal or the carboxyl terminal, 19 types were identified with high accuracy. Even for dipeptides with lower identification accuracy, it was confirmed that they were recognized as one of the dipeptides with high structural similarity, such as cyclic structures and branched amino acids. Moreover, pathophysiologically relevant sequence differences in β-amyloid peptides were accurately discriminated with a sensitivity of approximately 975 zeptomoles.
{"title":"Rapid Surface-Enhanced Raman Scattering Imaging and Deep Learning for Highly Sensitive Discrimination of Amino Acids and Peptides","authors":"Masaya Okada, Kazuki Bando, Yuki Shimaoka, Yasunori Nawa, Kosuke Okada, Satoshi Fujita, Katsumasa Fujita, Shigeki Iwanaga","doi":"10.1021/acs.jpcc.4c02246","DOIUrl":"https://doi.org/10.1021/acs.jpcc.4c02246","url":null,"abstract":"Developing a highly sensitive and accurate method to discriminate between amino acids and peptides is vital for establishing future healthcare testing technologies, such as liquid biopsy. This study proposes a highly sensitive technique based on surface-enhanced Raman scattering (SERS), which combines chemically linking an analyte with gold nanoparticles and aggregating them to produce hotspots. Furthermore, by combining rapid SERS imaging with slit-scanning Raman microscopy and deep learning based on a convolutional neural network, 20 proteinogenic amino acids were successfully detected and distinguished with accuracies exceeding 95%. Also, out of 39 types of dipeptides that have Phe at either the amino terminal or the carboxyl terminal, 19 types were identified with high accuracy. Even for dipeptides with lower identification accuracy, it was confirmed that they were recognized as one of the dipeptides with high structural similarity, such as cyclic structures and branched amino acids. Moreover, pathophysiologically relevant sequence differences in β-amyloid peptides were accurately discriminated with a sensitivity of approximately 975 zeptomoles.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"21 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-18DOI: 10.1021/acs.jpcc.4c06343
Daoyu Zhang, Yinhao Zhao, Minnan Yang
Using two-dimensional (2D) semiconductors as channel materials of field-effect transistors (FETs) has made significant advances in recent years. However, the relevant theory lags behind experiment. For example, the current–voltage relationship for 3D FET devices has still been used to analyze the performance parameters of 2D FETs. Here, we reexamine the relationship for 3D FETs and find that the concept of threshold voltage in it is not valid for 2D ones because 2D channel semiconductors with atomic-level thickness do not have the concept of surface potential used to define the threshold voltage of 3D FETs. From the current–voltage relationship derived by us for 2D back-gate FETs, the theoretical expression of the 2D threshold voltage is extracted, which describes a particular gate voltage that causes a 2D channel material going into the critical state of degeneracy, and it depends on the parameters such as the ideal work-affinity difference, the net charge in the oxide, and the applied drain voltage. The relevant experimental data also support our theoretical definition of the threshold voltage. The parameters present in the 2D threshold voltage can provide theoretical guidance on the modulation of the threshold voltage of 2D FETs.
{"title":"Theoretical Threshold Voltage of Two-Dimensional Semiconductor Field-Effect Transistors","authors":"Daoyu Zhang, Yinhao Zhao, Minnan Yang","doi":"10.1021/acs.jpcc.4c06343","DOIUrl":"https://doi.org/10.1021/acs.jpcc.4c06343","url":null,"abstract":"Using two-dimensional (2D) semiconductors as channel materials of field-effect transistors (FETs) has made significant advances in recent years. However, the relevant theory lags behind experiment. For example, the current–voltage relationship for 3D FET devices has still been used to analyze the performance parameters of 2D FETs. Here, we reexamine the relationship for 3D FETs and find that the concept of threshold voltage in it is not valid for 2D ones because 2D channel semiconductors with atomic-level thickness do not have the concept of surface potential used to define the threshold voltage of 3D FETs. From the current–voltage relationship derived by us for 2D back-gate FETs, the theoretical expression of the 2D threshold voltage is extracted, which describes a particular gate voltage that causes a 2D channel material going into the critical state of degeneracy, and it depends on the parameters such as the ideal work-affinity difference, the net charge in the oxide, and the applied drain voltage. The relevant experimental data also support our theoretical definition of the threshold voltage. The parameters present in the 2D threshold voltage can provide theoretical guidance on the modulation of the threshold voltage of 2D FETs.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"69 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142671109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coating a substrate with a self-assembled monolayer (SAM) is known as an effective surface modification method for improving the quality of organic semiconductor films formed on it. However, there is still a lack of comprehensive understanding regarding the formation of molecular orientation on SAM surfaces. Highly ordered SAMs were prepared on SiO2 substrates using octadecyltrichlorosilane (OTS). The temperature dependence of the molecular orientation of pentacene films prepared on the OTS substrates was investigated by p-polarized multiple-angle incidence resolution spectrometry (pMAIRS). It was found that pentacene molecules had standing orientations preferentially on the OTS surface regardless of the growth temperature. This indicates that the interaction between the OTS surface and the lying molecules is small, and the self-assembling of the molecules and the formation of standing-oriented crystallites are promoted even when the kinetic energy of depositing molecules is low.
众所周知，在基底上涂覆自组装单层（SAM）是一种有效的表面改性方法，可提高在基底上形成的有机半导体薄膜的质量。然而，人们对 SAM 表面分子取向的形成仍缺乏全面的了解。研究人员使用十八烷基三氯硅烷（OTS）在二氧化硅基底上制备了高度有序的 SAM。通过对偏振多角入射分辨光谱法（pMAIRS）研究了在 OTS 基底上制备的并五苯薄膜分子取向的温度依赖性。结果发现，无论生长温度如何，并五苯分子都优先在 OTS 表面上驻留取向。这表明 OTS 表面与静止分子之间的相互作用很小，即使沉积分子的动能很低，也能促进分子的自组装和静止取向晶体的形成。
{"title":"Standing Orientation of Pentacene Promoted on Octadecyltrichlorosilane Self-Assembled Monolayers Revealed by pMAIRS","authors":"Sae Nagai, Nobutaka Shioya, Takeshi Hasegawa, Taka-aki Ishibashi","doi":"10.1021/acs.jpcc.4c04062","DOIUrl":"https://doi.org/10.1021/acs.jpcc.4c04062","url":null,"abstract":"Coating a substrate with a self-assembled monolayer (SAM) is known as an effective surface modification method for improving the quality of organic semiconductor films formed on it. However, there is still a lack of comprehensive understanding regarding the formation of molecular orientation on SAM surfaces. Highly ordered SAMs were prepared on SiO<sub>2</sub> substrates using octadecyltrichlorosilane (OTS). The temperature dependence of the molecular orientation of pentacene films prepared on the OTS substrates was investigated by p-polarized multiple-angle incidence resolution spectrometry (pMAIRS). It was found that pentacene molecules had standing orientations preferentially on the OTS surface regardless of the growth temperature. This indicates that the interaction between the OTS surface and the lying molecules is small, and the self-assembling of the molecules and the formation of standing-oriented crystallites are promoted even when the kinetic energy of depositing molecules is low.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"11 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142671108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-17DOI: 10.1021/acs.jpcc.4c04988
Andrew J. E. Rowberg, Chris G. Van de Walle
Yttrium oxyhydride (YHO) undergoes a reversible photochromic transition when exposed to ultraviolet light. However, the mechanism for this transformation is not fully understood, and the structure and precise chemical composition of YHO remain under debate. Here, we use first-principles density functional theory calculations with a hybrid functional to study the structure, chemical stability, and point defect properties of YHO. As experiments have shown, we find that YHO prefers a cubic structure, with H and O anions present in equal concentrations and located on tetrahedral sites. Stoichiometric and ordered YHO is chemically stable, but it has a wide band gap of 5.01 eV, considerably larger than that measured in experiments (2.4–3.8 eV). On the other hand, Y4H10O has a smaller band gap of 2.97 eV and also has a region of chemical stability; thus, the actual material may include some fraction of this H-rich structure. The defect chemistry of YHO is dominated by anionic antisite species (HO and OH), with hydrogen interstitials (Hi) and vacancies (VH) also present in reasonably high concentrations. We show that antisite disorder lowers the band gap relative to the perfectly ordered structure, bringing the magnitude of the gap into closer agreement with experiment. Based on our calculations of defect migration and the positions of defect states relative to the band edges, we link the onset of photochromic behavior to the reaction HO– → VO0 + Hi–, which follows photoexcitation of a HO+ defect. Hi– can subsequently migrate away and be trapped by additional HO+ defects, contributing to the persistence of the reaction, while the resultant oxygen vacancy, VO0, introduces an occupied defect state that leads to optical absorption at visible wavelengths. Our results can explain reported discrepancies between experimental and computational results for YHO, and they allow us to propose specific atomic-scale processes that can lead to photochromism. Understanding these mechanisms is key for unlocking YHO’s application in devices ranging from smart windows and optoelectronics to electrochemical synapses for neural networks.
{"title":"Defect Properties, Anion Ordering, and Photochromic Mechanism in Yttrium Oxyhydride","authors":"Andrew J. E. Rowberg, Chris G. Van de Walle","doi":"10.1021/acs.jpcc.4c04988","DOIUrl":"https://doi.org/10.1021/acs.jpcc.4c04988","url":null,"abstract":"Yttrium oxyhydride (YHO) undergoes a reversible photochromic transition when exposed to ultraviolet light. However, the mechanism for this transformation is not fully understood, and the structure and precise chemical composition of YHO remain under debate. Here, we use first-principles density functional theory calculations with a hybrid functional to study the structure, chemical stability, and point defect properties of YHO. As experiments have shown, we find that YHO prefers a cubic structure, with H and O anions present in equal concentrations and located on tetrahedral sites. Stoichiometric and ordered YHO is chemically stable, but it has a wide band gap of 5.01 eV, considerably larger than that measured in experiments (2.4–3.8 eV). On the other hand, Y<sub>4</sub>H<sub>10</sub>O has a smaller band gap of 2.97 eV and also has a region of chemical stability; thus, the actual material may include some fraction of this H-rich structure. The defect chemistry of YHO is dominated by anionic antisite species (H<sub>O</sub> and O<sub>H</sub>), with hydrogen interstitials (H<sub><i>i</i></sub>) and vacancies (<i>V</i><sub>H</sub>) also present in reasonably high concentrations. We show that antisite disorder lowers the band gap relative to the perfectly ordered structure, bringing the magnitude of the gap into closer agreement with experiment. Based on our calculations of defect migration and the positions of defect states relative to the band edges, we link the onset of photochromic behavior to the reaction H<sub>O</sub><sup>–</sup> → <i>V</i><sub>O</sub><sup>0</sup> + H<sub><i>i</i></sub><sup>–</sup>, which follows photoexcitation of a H<sub>O</sub><sup>+</sup> defect. H<sub><i>i</i></sub><sup>–</sup> can subsequently migrate away and be trapped by additional H<sub>O</sub><sup>+</sup> defects, contributing to the persistence of the reaction, while the resultant oxygen vacancy, <i>V</i><sub>O</sub><sup>0</sup>, introduces an occupied defect state that leads to optical absorption at visible wavelengths. Our results can explain reported discrepancies between experimental and computational results for YHO, and they allow us to propose specific atomic-scale processes that can lead to photochromism. Understanding these mechanisms is key for unlocking YHO’s application in devices ranging from smart windows and optoelectronics to electrochemical synapses for neural networks.","PeriodicalId":61,"journal":{"name":"The Journal of Physical Chemistry C","volume":"7 1","pages":""},"PeriodicalIF":4.126,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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