One of the key challenges in the large‐scale application of perovskite solar cells is stability. Researchers have found that passivation molecules play a crucial role in mitigating interface defects, thereby enhancing stability. Traditionally, the design of passivation molecules has relied on the expertise of chemists and materials scientists. In this study, we introduce a novel approach driven by a language model and dipole‐moment‐knowledge‐based strategy for passivation molecule design. Specifically, we employ the open‐source Gemma model, which is pre‐trained and fine‐tuned on the PubChem and QM9 datasets. This fine‐tuning enables Gemma to generate passivation molecules with higher dipole moments. Further density functional theory (DFT) validation reveals that molecules designed by Gemma improve the stability of perovskite structures with surface defects by approximately 27.75%. Additionally, electronic density of states and charge distribution analysis further support these findings. This study highlights the potential of language models in the design of next‐generation photovoltaic device materials, particularly in passivation molecule development.
{"title":"Dipole‐Moment‐Knowledge‐Guided Molecular Design for Perovskite Surface Passivation: A Gemma‐Language‐Model and DFT‐Driven Framework","authors":"Tianhui Jiang, Yifeng Gao, Guozhen Liu, Guoxiang Zhao, Junjie Hu, Rongjian Sa, Peng Gao","doi":"10.1002/adts.202501318","DOIUrl":"https://doi.org/10.1002/adts.202501318","url":null,"abstract":"One of the key challenges in the large‐scale application of perovskite solar cells is stability. Researchers have found that passivation molecules play a crucial role in mitigating interface defects, thereby enhancing stability. Traditionally, the design of passivation molecules has relied on the expertise of chemists and materials scientists. In this study, we introduce a novel approach driven by a language model and dipole‐moment‐knowledge‐based strategy for passivation molecule design. Specifically, we employ the open‐source Gemma model, which is pre‐trained and fine‐tuned on the PubChem and QM9 datasets. This fine‐tuning enables Gemma to generate passivation molecules with higher dipole moments. Further density functional theory (DFT) validation reveals that molecules designed by Gemma improve the stability of perovskite structures with surface defects by approximately 27.75%. Additionally, electronic density of states and charge distribution analysis further support these findings. This study highlights the potential of language models in the design of next‐generation photovoltaic device materials, particularly in passivation molecule development.","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"75 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145559563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Natthapong Jampaiboon, Chayanon Atthapak, Thiti Bovornratanaraks, Björn Alling, Annop Ektarawong
This study presents a comprehensive first‐principles investigation of and , focusing on their thermodynamic stability and mechanical behavior. The results reveal that, at absolute zero, Hf‐rich with , is thermodynamically stable, whereas Y‐rich with and with are unstable against decomposition into relevant competing phases, i.e., solid solution and for Y‐rich and , and ‐rhombohedral B for . However, near‐stability of Y‐rich , where , with formation energies within 4 meV per atom above the Hf−Y−B convex hull implies its potential entropy‐driven thermodynamic stabilization at elevated temperatures. Both and are mechanically stable, according to the Born stability criteria, and Vegard's law is largely obeyed for their structural parameters and elastic moduli. Hf‐rich exhibits superhard behavior with a maximum Vickers hardness of 43.9 GPa at = 0.167, while that of ranges between 33 and 39 GPa and peaks at 38.2 GPa for = 0.875. The maximum Vickers hardness values of and surpass those of their constituent compounds. These findings offer fundamental insights into stabilities and mechanical performance of the − and − mixtures, providing theoretical guidance for future development of advanced metal boride‐based hard‐coating materials.
{"title":"Thermodynamic Consideration and Mechanical Behavior of Boride‐Containing Solid Solutions of Hafnium−Yttrium−Boron System Revealed by a First‐Principles Analysis","authors":"Natthapong Jampaiboon, Chayanon Atthapak, Thiti Bovornratanaraks, Björn Alling, Annop Ektarawong","doi":"10.1002/adts.202501517","DOIUrl":"https://doi.org/10.1002/adts.202501517","url":null,"abstract":"This study presents a comprehensive first‐principles investigation of and , focusing on their thermodynamic stability and mechanical behavior. The results reveal that, at absolute zero, Hf‐rich with , is thermodynamically stable, whereas Y‐rich with and with are unstable against decomposition into relevant competing phases, i.e., solid solution and for Y‐rich and , and ‐rhombohedral B for . However, near‐stability of Y‐rich , where , with formation energies within 4 meV per atom above the Hf−Y−B convex hull implies its potential entropy‐driven thermodynamic stabilization at elevated temperatures. Both and are mechanically stable, according to the Born stability criteria, and Vegard's law is largely obeyed for their structural parameters and elastic moduli. Hf‐rich exhibits superhard behavior with a maximum Vickers hardness of 43.9 GPa at = 0.167, while that of ranges between 33 and 39 GPa and peaks at 38.2 GPa for = 0.875. The maximum Vickers hardness values of and surpass those of their constituent compounds. These findings offer fundamental insights into stabilities and mechanical performance of the − and − mixtures, providing theoretical guidance for future development of advanced metal boride‐based hard‐coating materials.","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"28 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145535429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Technology Computer-Aided Design (TCAD) modeling is a vital tool for the design of complex optoelectronic devices such as III-V multijunction solar cells. In this work, Bayesian optimization is proposed as a robust framework that is able to tackle difficulties that arise in the optimization of expensive to evaluate black-box functions, such as TCAD solvers. This method is applied to a lattice-matched GaInP/Ga(In)As/Ge triple junction solar cell, which incorporates a distributed Bragg reflector for space applications. The results show a path to increase the efficiency of current commercial space triple junction solar cells.
{"title":"Using Bayesian Optimization to Increase the Efficiency of III-V Multijunction Solar Cells","authors":"Pablo F. Palacios, Carlos Algora","doi":"10.1002/adts.202500821","DOIUrl":"https://doi.org/10.1002/adts.202500821","url":null,"abstract":"Technology Computer-Aided Design (TCAD) modeling is a vital tool for the design of complex optoelectronic devices such as III-V multijunction solar cells. In this work, Bayesian optimization is proposed as a robust framework that is able to tackle difficulties that arise in the optimization of expensive to evaluate black-box functions, such as TCAD solvers. This method is applied to a lattice-matched GaInP/Ga(In)As/Ge triple junction solar cell, which incorporates a distributed Bragg reflector for space applications. The results show a path to increase the efficiency of current commercial space triple junction solar cells.","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"127 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145531882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The proposed perovskite device structure considers several factors to realize their significance on device performance. Initially, the PCE variation between the two absorber halides is investigated, yielding a maximum PCE of 24.31% for CH3NH3SnBr3 and 27.37% for CH3NH3SnI3. Additionally, the SCAPS‐1D simulation assesses the contribution of distinct HTMs and ETMs. By further optimizing these layers along with diverse intrinsic parameters, the device's PCE increased from 27.37% to 40.17%. To improve predictive capabilities, a dataset of 29565 is generated utilizing the SCAPS‐1D simulator for CH3NH3SnI3‐based solar cells. Data preprocessing in Python applied leakage‐safe Pearson correlation filtering: within each highly collinear group (|r| ≥ 0.90), one representative predictor is retained and the remainder are excluded to reduce multicollinearity and improve interpretability. Six machine learning models are tested, and Random Forest is validated to be the most credible performer with an R2 of 96% and an RMSE of 0.210. The optimized configuration — FTO/WS 2 (ETL)/CH 3 NH 3 SnI 3 (absorber)/V 2 O 5 (HTL)/Pt (back contact) — achieves a record simulated efficiency of 40.17%, surpassing prior reports. This performance is attributed to WS 2 ’s favorable band alignment, CH 3 NH 3 SnI 3 ’s strong absorption, and V 2 O 5 ’s stability. The combined SCAPS–ML framework not only accelerates optimization but also provides actionable design rules for environmentally sustainable, lead‐free PSCs.
{"title":"Optimization of Lead‐Free Perovskite Solar Cell Architecture Using Machine Learning and Numerical Simulations","authors":"Md. Arifur Rahman, Mohammad Jahangir Alam","doi":"10.1002/adts.202501590","DOIUrl":"https://doi.org/10.1002/adts.202501590","url":null,"abstract":"The proposed perovskite device structure considers several factors to realize their significance on device performance. Initially, the PCE variation between the two absorber halides is investigated, yielding a maximum PCE of 24.31% for CH3NH3SnBr3 and 27.37% for CH3NH3SnI3. Additionally, the SCAPS‐1D simulation assesses the contribution of distinct HTMs and ETMs. By further optimizing these layers along with diverse intrinsic parameters, the device's PCE increased from 27.37% to 40.17%. To improve predictive capabilities, a dataset of 29565 is generated utilizing the SCAPS‐1D simulator for CH3NH3SnI3‐based solar cells. Data preprocessing in Python applied leakage‐safe Pearson correlation filtering: within each highly collinear group (|r| ≥ 0.90), one representative predictor is retained and the remainder are excluded to reduce multicollinearity and improve interpretability. Six machine learning models are tested, and Random Forest is validated to be the most credible performer with an R2 of 96% and an RMSE of 0.210. The optimized configuration — FTO/WS <jats:sub>2</jats:sub> (ETL)/CH <jats:sub>3</jats:sub> NH <jats:sub>3</jats:sub> SnI <jats:sub>3</jats:sub> (absorber)/V <jats:sub>2</jats:sub> O <jats:sub>5</jats:sub> (HTL)/Pt (back contact) — achieves a record simulated efficiency of 40.17%, surpassing prior reports. This performance is attributed to WS <jats:sub>2</jats:sub> ’s favorable band alignment, CH <jats:sub>3</jats:sub> NH <jats:sub>3</jats:sub> SnI <jats:sub>3</jats:sub> ’s strong absorption, and V <jats:sub>2</jats:sub> O <jats:sub>5</jats:sub> ’s stability. The combined SCAPS–ML framework not only accelerates optimization but also provides actionable design rules for environmentally sustainable, lead‐free PSCs.","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"171 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145509681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chandon Sarker, Sushmita Sadhu Pakhi, M. N. H. Liton, M. R. Islam, Mst. H. Khatun, Mohammad Kamal Hossain, M. Shahjahan, Arpon Chakraborty
This study compiles the structural, mechanical, bonding, and dynamical characteristics of the recently synthesized rare earth metallic compounds MC 2 B 2 (M = Lu, La) by means of density functional theory (DFT). Both LuC 2 B 2 and LaC 2 B 2 crystallize in tetragonal symmetry. The negative cohesive energy of LuC 2 B 2 (−7.824 eV atom −1 ) and LaC 2 B 2 (−7.692 eV atom −1 ) ensured the stability of both compounds. The compounds exhibit mechanical stability with significant elastic anisotropy, ductility, and high hardness (22.84 and 21.84 GPa for LuC 2 B 2 and LaC 2 B 2 , respectively). The electronic band structures and density of states (DOS) indicate metallic behavior, predominantly influenced by Lu/La‐5d, B‐2p, and C‐2p states, showing mixed bonding characteristics with ionic and covalent contributions. Both compounds are hard and brittle in nature. Possessing a high melting point (2183.06 K for LuC 2 B 2 and 1873.82 K for LaC 2 B 2 ), the compounds are suitable for applications in thermally harsh conditions. Through Drude‐like low‐energy behavior, optical properties also confirmed metallic nature and showed significant reflection and absorption with a specific directional dependence, especially LuC 2 B 2 shows exceptional reflectivity (≈80%) in the infrared (IR) to lower upper ultraviolet (UV) regions. The findings collectively demonstrate that LuC 2 B 2 and LaC 2 B 2 are viable options for cutting‐edge technological applications that demand superior optoelectronic, thermophysical, and mechanical performance.
{"title":"Exploring the Multifunctional Properties of MC 2 B 2 (M = Lu, La) Structures Using Density Functional Theory","authors":"Chandon Sarker, Sushmita Sadhu Pakhi, M. N. H. Liton, M. R. Islam, Mst. H. Khatun, Mohammad Kamal Hossain, M. Shahjahan, Arpon Chakraborty","doi":"10.1002/adts.202501440","DOIUrl":"https://doi.org/10.1002/adts.202501440","url":null,"abstract":"This study compiles the structural, mechanical, bonding, and dynamical characteristics of the recently synthesized rare earth metallic compounds MC <jats:sub>2</jats:sub> B <jats:sub>2</jats:sub> (M = Lu, La) by means of density functional theory (DFT). Both LuC <jats:sub>2</jats:sub> B <jats:sub>2</jats:sub> and LaC <jats:sub>2</jats:sub> B <jats:sub>2</jats:sub> crystallize in tetragonal symmetry. The negative cohesive energy of LuC <jats:sub>2</jats:sub> B <jats:sub>2</jats:sub> (−7.824 eV atom <jats:sup>−1</jats:sup> ) and LaC <jats:sub>2</jats:sub> B <jats:sub>2</jats:sub> (−7.692 eV atom <jats:sup>−1</jats:sup> ) ensured the stability of both compounds. The compounds exhibit mechanical stability with significant elastic anisotropy, ductility, and high hardness (22.84 and 21.84 GPa for LuC <jats:sub>2</jats:sub> B <jats:sub>2</jats:sub> and LaC <jats:sub>2</jats:sub> B <jats:sub>2</jats:sub> , respectively). The electronic band structures and density of states (DOS) indicate metallic behavior, predominantly influenced by Lu/La‐5d, B‐2p, and C‐2p states, showing mixed bonding characteristics with ionic and covalent contributions. Both compounds are hard and brittle in nature. Possessing a high melting point (2183.06 K for LuC <jats:sub>2</jats:sub> B <jats:sub>2</jats:sub> and 1873.82 K for LaC <jats:sub>2</jats:sub> B <jats:sub>2</jats:sub> ), the compounds are suitable for applications in thermally harsh conditions. Through Drude‐like low‐energy behavior, optical properties also confirmed metallic nature and showed significant reflection and absorption with a specific directional dependence, especially LuC <jats:sub>2</jats:sub> B <jats:sub>2</jats:sub> shows exceptional reflectivity (≈80%) in the infrared (IR) to lower upper ultraviolet (UV) regions. The findings collectively demonstrate that LuC <jats:sub>2</jats:sub> B <jats:sub>2</jats:sub> and LaC <jats:sub>2</jats:sub> B <jats:sub>2</jats:sub> are viable options for cutting‐edge technological applications that demand superior optoelectronic, thermophysical, and mechanical performance.","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"184 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145509679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Ouadha, M. H. Elahmar, H. Rached, M. Caid, D. Rached, Y. Rached, S. Al‐Qaisi, A. Boutramine, N. Hacini
MAX phases, which combine metallic and ceramic characteristics, are promising candidates for operation in extreme environments owing to their exceptional structural and functional versatility. This study employs first principles density functional theory (DFT) to investigate the stability, mechanical anisotropy, and optical response of the novel M 4 GaC 3 (M = V, Nb, and Ta) MAX‐phases. All three compounds are confirmed to be thermodynamically and mechanically stable. A key finding is their outstanding performance, exhibiting ultra‐high stiffness and strong thermal resilience, which establishes their suitability for extreme thermomechanical conditions. Electronic structure analysis confirms metallic conductivity, while the optical spectra reveal high reflectivity in the visible and infrared ranges. These first‐principles predictions provide critical design insights, identifying the M 4 GaC 3 family as promising multifunctional materials for structural and functional roles in aerospace and high‐performance energy systems.
{"title":"Computational Design of M 4 GaC 3 (M = V, Nb, Ta) MAX‐Phases: Stability, Mechanical Strength, and Optical Response Under High Pressure and Temperature","authors":"I. Ouadha, M. H. Elahmar, H. Rached, M. Caid, D. Rached, Y. Rached, S. Al‐Qaisi, A. Boutramine, N. Hacini","doi":"10.1002/adts.202501514","DOIUrl":"https://doi.org/10.1002/adts.202501514","url":null,"abstract":"MAX phases, which combine metallic and ceramic characteristics, are promising candidates for operation in extreme environments owing to their exceptional structural and functional versatility. This study employs first principles density functional theory (DFT) to investigate the stability, mechanical anisotropy, and optical response of the novel M <jats:sub>4</jats:sub> GaC <jats:sub>3</jats:sub> (M = V, Nb, and Ta) MAX‐phases. All three compounds are confirmed to be thermodynamically and mechanically stable. A key finding is their outstanding performance, exhibiting ultra‐high stiffness and strong thermal resilience, which establishes their suitability for extreme thermomechanical conditions. Electronic structure analysis confirms metallic conductivity, while the optical spectra reveal high reflectivity in the visible and infrared ranges. These first‐principles predictions provide critical design insights, identifying the M <jats:sub>4</jats:sub> GaC <jats:sub>3</jats:sub> family as promising multifunctional materials for structural and functional roles in aerospace and high‐performance energy systems.","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"21 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145499106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuxuan Cao, Wei Zhou, Guangxiong Luo, Chenxi Zhang, C. P. Liang
This study employs semiempirical molecular orbital methods to evaluate the electronic and solvation characteristics of five common molecules as electrolyte additives and co‐solvents for alkali metal batteries. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) suggest that 1,2‐dimethoxyethane (DME), 1,2‐diethoxyethanes (DEE) and 1,3‐dioxolane (DOL) exhibit suitable redox activity for electrochemical process. However, after binding with one Li ion, DME distinguishes itself as a more promising solvent for alkali metal batteries. The solvation structure of DME with alkali metal ions is investigated. The geometric relaxation and electronic transfer imply that partial crystallization happens as the number of DME reaches the saturation point (maximum three DMEs). This crystallization improves the electrochemical stability and mediates the redox activity. In addition, fluorination of DME enhance DME's oxidation resistance and chemical stability, and partial fluorination with 4 F atoms (F4DME) displays the optimum properties. On the other hand, fluorination destabilizes the solvation structures with alkali metal ions, and reduces the saturated DMEs from three to two. The desolvation tendency and enhanced binding energy provide a viable way to tune the electrochemical performance of solvent, and thus enable a balance between chemical stability and electrochemical kinetics.
{"title":"Theoretical Screening for Electronic and Solvation Characteristics of Common Molecules as Electrolyte Additives and Co‐Solvents for Alkali Metal Batteries","authors":"Yuxuan Cao, Wei Zhou, Guangxiong Luo, Chenxi Zhang, C. P. Liang","doi":"10.1002/adts.202500767","DOIUrl":"https://doi.org/10.1002/adts.202500767","url":null,"abstract":"This study employs semiempirical molecular orbital methods to evaluate the electronic and solvation characteristics of five common molecules as electrolyte additives and co‐solvents for alkali metal batteries. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) suggest that 1,2‐dimethoxyethane (DME), 1,2‐diethoxyethanes (DEE) and 1,3‐dioxolane (DOL) exhibit suitable redox activity for electrochemical process. However, after binding with one Li ion, DME distinguishes itself as a more promising solvent for alkali metal batteries. The solvation structure of DME with alkali metal ions is investigated. The geometric relaxation and electronic transfer imply that partial crystallization happens as the number of DME reaches the saturation point (maximum three DMEs). This crystallization improves the electrochemical stability and mediates the redox activity. In addition, fluorination of DME enhance DME's oxidation resistance and chemical stability, and partial fluorination with 4 F atoms (F4DME) displays the optimum properties. On the other hand, fluorination destabilizes the solvation structures with alkali metal ions, and reduces the saturated DMEs from three to two. The desolvation tendency and enhanced binding energy provide a viable way to tune the electrochemical performance of solvent, and thus enable a balance between chemical stability and electrochemical kinetics.","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"368 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145491953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article develops a variational formulation for modeling a silicon semiconductor through a multi‐well approach utilizing phosphorus atoms as a dopant substance. The results are based on standard tools of calculus of variations and optimization theory. It is worth highlighting, the variational formulation here developed may be used to find an optimal phosphorus density distribution concerning an originally silicon density, in order to maximize the electrical conductivity of such a sample. Finally, in the last section, a numerical example is presented to illustrate the applicability of such results developed in the previous sections.
{"title":"A Variational Formulation for Modeling a Phosphorus Doped Silicon Semiconductor Through a Multi‐Well Approach","authors":"Fabio Silva Botelho","doi":"10.1002/adts.202501365","DOIUrl":"https://doi.org/10.1002/adts.202501365","url":null,"abstract":"This article develops a variational formulation for modeling a silicon semiconductor through a multi‐well approach utilizing phosphorus atoms as a dopant substance. The results are based on standard tools of calculus of variations and optimization theory. It is worth highlighting, the variational formulation here developed may be used to find an optimal phosphorus density distribution concerning an originally silicon density, in order to maximize the electrical conductivity of such a sample. Finally, in the last section, a numerical example is presented to illustrate the applicability of such results developed in the previous sections.","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"39 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145492387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Leonardo S. Barbosa, Willian O. Santos, Felix S. Costa, Edvan Moreira, David L. Azevedo
Niobium‐based MXenes show promising properties and applications, but have not yet been sufficiently investigated, especially with halogen surface terminations. This study investigates the structural, electronic, optical, vibrational, and thermodynamic properties of the unique trigonal (Nb‐MXene) monolayer using the density functional theory (DFT) formalism with the GGA‐PBE functional. The results of the lattice parameters and bond lengths are compared with the theoretical and experimental data for similar structures. The monolayer exhibits structural stability, since the phonon dispersion results do not reveal negative frequencies, with a cohesive energy of 4.36 eV per atom, and a negative formation energy of –3.85 eV, confirming thermodynamic stability. The band structure indicates that Nb‐MXene is a metal with potential applications as a supercapacitor, as well as revealing potential superconductor characteristics. The optical absorption properties reveal that Nb‐MXene is sensitive to the plane of polarization of incident light, absorbs in the visible region (400–700 nm), and has potential applications as a UVC (100–280 nm) optical filter and as an optical fiber sensor. Thermodynamic properties as a function of temperature are calculated up to 1000 K to characterize the stability of Nb‐MXene. Infrared (IR) and Raman spectra are calculated and assigned, serving as a useful theoretical reference for experimental monolayer characterization. The findings suggest that Nb‐MXene is a promising candidate for photonic and biomedical applications.
{"title":"Nb 2 CBr 2 MXene Monolayer as a Novel Material: A First Principle Study","authors":"Leonardo S. Barbosa, Willian O. Santos, Felix S. Costa, Edvan Moreira, David L. Azevedo","doi":"10.1002/adts.202500983","DOIUrl":"https://doi.org/10.1002/adts.202500983","url":null,"abstract":"Niobium‐based MXenes show promising properties and applications, but have not yet been sufficiently investigated, especially with halogen surface terminations. This study investigates the structural, electronic, optical, vibrational, and thermodynamic properties of the unique trigonal (Nb‐MXene) monolayer using the density functional theory (DFT) formalism with the GGA‐PBE functional. The results of the lattice parameters and bond lengths are compared with the theoretical and experimental data for similar structures. The monolayer exhibits structural stability, since the phonon dispersion results do not reveal negative frequencies, with a cohesive energy of 4.36 eV per atom, and a negative formation energy of –3.85 eV, confirming thermodynamic stability. The band structure indicates that Nb‐MXene is a metal with potential applications as a supercapacitor, as well as revealing potential superconductor characteristics. The optical absorption properties reveal that Nb‐MXene is sensitive to the plane of polarization of incident light, absorbs in the visible region (400–700 nm), and has potential applications as a UVC (100–280 nm) optical filter and as an optical fiber sensor. Thermodynamic properties as a function of temperature are calculated up to 1000 K to characterize the stability of Nb‐MXene. Infrared (IR) and Raman spectra are calculated and assigned, serving as a useful theoretical reference for experimental monolayer characterization. The findings suggest that Nb‐MXene is a promising candidate for photonic and biomedical applications.","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"1 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145491955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Additives, such as hydrate promoters or inhibitors, play a crucial role in hydrate growth by altering the thermodynamics or kinetics during the formation of hydrates. Ethylenediaminetetracetic acid (EDTA) bisamide can act as methane hydrate promoter or inhibitor based on length of alkyl side group due to shorter or longer alkyl chains, respectively. Molecular dynamics simulations effect of EDTA bisamide are reported with longer alkyl (n-heptyl) side group on selective sequestration of carbon dioxide during CH4-CO2 exchange in natural gas hydrates in a ternary-gas system with different third gas species (N2, H2S, Ar, Kr, and Xe). The results show there is formation of gas cluster in bulk liquid region due to hydrophobic tails of EDTA bisamide. The lifetime of Xe and CH4 clusters is the longest among the reported systems due to favorable interactions between Xe and CH4. The carbon dioxide sequestration in the newly formed sI-hydrate cages is the highest for Xe(3:1) system, followed by N2(2:2), and is the poorest in Ar(2.5:1.5) and H2S(2:2) systems. Xe and Ar show reverse trends in sequestration of carbon dioxide in presence of EDTA bisamide as compared to the earlier reported simulations in a ternary-gas system in the absence of additives (PCCP, 2023, 25, 30211–3022).
添加剂，如水合物促进剂或抑制剂，通过改变水合物形成过程中的热力学或动力学，在水合物生长中起着至关重要的作用。乙二胺四乙酸（EDTA）双酰胺由于烷基链较短或较长，根据烷基侧基的长度可以分别作为甲烷水合物的促进剂或抑制剂。本文报道了具有较长烷基（正庚基）侧基的EDTA双酰胺在具有不同第三种气体（n2、h2、Ar、Kr和Xe）的三元气体体系中，对天然气水合物中ch4 - CO 2交换过程中二氧化碳选择性封存的分子动力学模拟效应。结果表明，EDTA双酰胺的疏水尾部在体液区形成气团。由于Xe和ch4之间有利的相互作用，Xe和ch4簇的寿命是所报道的系统中最长的。在新形成的sI水合物笼中，二氧化碳固存在Xe（3:1）体系中最高，其次是n2（2:2）体系，而在Ar（2.5:1.5）和h2s（2:2）体系中最低。与之前报道的在没有添加剂的三元气体系统中进行的模拟相比，在EDTA双酰胺存在的情况下，Xe和Ar对二氧化碳的固存趋势相反（PCCP, 2023, 25, 30211-3022）。
{"title":"Molecular Dynamics Investigations Into Role of EDTA Bisamide in CO2-CH4 Exchange in NGHs in Presence of Flue and Noble Gases","authors":"Satyam Singh, Manju Sharma","doi":"10.1002/adts.202500649","DOIUrl":"10.1002/adts.202500649","url":null,"abstract":"<p>Additives, such as hydrate promoters or inhibitors, play a crucial role in hydrate growth by altering the thermodynamics or kinetics during the formation of hydrates. Ethylenediaminetetracetic acid (EDTA) bisamide can act as methane hydrate promoter or inhibitor based on length of alkyl side group due to shorter or longer alkyl chains, respectively. Molecular dynamics simulations effect of EDTA bisamide are reported with longer alkyl (n-heptyl) side group on selective sequestration of carbon dioxide during CH<sub>4</sub>-CO<sub>2</sub> exchange in natural gas hydrates in a ternary-gas system with different third gas species (N<sub>2</sub>, H<sub>2</sub>S, Ar, Kr, and Xe). The results show there is formation of gas cluster in bulk liquid region due to hydrophobic tails of EDTA bisamide. The lifetime of Xe and CH<sub>4</sub> clusters is the longest among the reported systems due to favorable interactions between Xe and CH<sub>4</sub>. The carbon dioxide sequestration in the newly formed sI-hydrate cages is the highest for Xe(3:1) system, followed by N<sub>2</sub>(2:2), and is the poorest in Ar(2.5:1.5) and H<sub>2</sub>S(2:2) systems. Xe and Ar show reverse trends in sequestration of carbon dioxide in presence of EDTA bisamide as compared to the earlier reported simulations in a ternary-gas system in the absence of additives (PCCP, 2023, <i>25</i>, 30211–3022).</p>","PeriodicalId":7219,"journal":{"name":"Advanced Theory and Simulations","volume":"8 12","pages":""},"PeriodicalIF":2.9,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145491952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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