Tawhid Pranto, Carla C. Fraenza, Frederik Philippi, Daniel Rauber, Christopher W. M. Kay, Tom Welton, Steven G. Greenbaum, Sophia Suarez
There is increasing interest in studying molecular motions in ionic liquids to gain better insights into their transport properties and to expand their applications. In this study, we have employed the fast field cycling relaxometry and pulsed field gradient nuclear magnetic resonance techniques to investigate the rotational and translational dynamics of fluorinated imide-based ionic liquids (ILs) at different temperatures. We have studied a total of six ILs composed of the 1-butyl-3-methylimidazolium cation ([BMIM]+) combined with chemically modified analogs of the bis((trifluoromethyl)sulfonyl)imide anion ([NTf2]− or [TFSI]−). The primary objective of this paper is to broaden the understanding of how the anion's conformational flexibility, fluorination, and mass affect the molecular dynamics of cations and anions. Our results indicate that flexibility has the most significant impact on the rotational and translational motions of ions. Meanwhile, the effect of fluorination and mass is only relevant when conformational flexibility does not change significantly between the ILs being compared.
{"title":"Dynamics of fluorinated imide-based ionic liquids using nuclear magnetic resonance techniques","authors":"Tawhid Pranto, Carla C. Fraenza, Frederik Philippi, Daniel Rauber, Christopher W. M. Kay, Tom Welton, Steven G. Greenbaum, Sophia Suarez","doi":"10.1039/d4cp03166k","DOIUrl":"https://doi.org/10.1039/d4cp03166k","url":null,"abstract":"There is increasing interest in studying molecular motions in ionic liquids to gain better insights into their transport properties and to expand their applications. In this study, we have employed the fast field cycling relaxometry and pulsed field gradient nuclear magnetic resonance techniques to investigate the rotational and translational dynamics of fluorinated imide-based ionic liquids (ILs) at different temperatures. We have studied a total of six ILs composed of the 1-butyl-3-methylimidazolium cation ([BMIM]<small><sup>+</sup></small>) combined with chemically modified analogs of the bis((trifluoromethyl)sulfonyl)imide anion ([NTf<small><sub>2</sub></small>]<small><sup>−</sup></small> or [TFSI]<small><sup>−</sup></small>). The primary objective of this paper is to broaden the understanding of how the anion's conformational flexibility, fluorination, and mass affect the molecular dynamics of cations and anions. Our results indicate that flexibility has the most significant impact on the rotational and translational motions of ions. Meanwhile, the effect of fluorination and mass is only relevant when conformational flexibility does not change significantly between the ILs being compared.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"12 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142968509","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}
Enci Zuo, Yingying Chen, Gang Jiang, Liang Zhao, Jiguang Du
In spite of a substantial amount of research has been conducted to unravel the structural configurations of selenium under pressure, the exquisite sensitivity of seleni-um's p-orbital electrons to this external force, leading to a plethora of structural varia-tions, leaves several intermediary phases still shrouded in mystery. We, herein, systemat-ically identify the structural and electronic transformations of selenium under high pres-sure up to 300 GPa, employing crystal structure prediction in conjunction with first-principles calculations. Our results for the transition sequence (P3121→C2/m→R3(_)m→Im3(_)m) of selenium are in good agreement with experimental ones. In particular, we first clarified the knowledge pertaining to the atomic arrangement within the monoclinic C2/m phase of selenium. Electron-phonon coupling calculations indicate that the super-conductivity observed in this material, akin to that in Tellurium, is realized via a phase transition. Furthermore, the superconducting critical temperature (Tc) displays a con-sistent rise as the material experiences high-pressure phase transitions from C2/m to R3(_)m and then to Im3(_)m, achieving a maximum Tc of 13.06 K in the Im3(_)m phase at 97.5 GPa. Our findings illuminate the path towards a deeper comprehension of the high-pressure structure and physics of selenium, prompting the need for innovative experi-mental and theoretical research.
{"title":"Phase transition and superconductivity of selenium under pressure","authors":"Enci Zuo, Yingying Chen, Gang Jiang, Liang Zhao, Jiguang Du","doi":"10.1039/d4cp04078c","DOIUrl":"https://doi.org/10.1039/d4cp04078c","url":null,"abstract":"In spite of a substantial amount of research has been conducted to unravel the structural configurations of selenium under pressure, the exquisite sensitivity of seleni-um's p-orbital electrons to this external force, leading to a plethora of structural varia-tions, leaves several intermediary phases still shrouded in mystery. We, herein, systemat-ically identify the structural and electronic transformations of selenium under high pres-sure up to 300 GPa, employing crystal structure prediction in conjunction with first-principles calculations. Our results for the transition sequence (P3121→C2/m→R3(_)m→Im3(_)m) of selenium are in good agreement with experimental ones. In particular, we first clarified the knowledge pertaining to the atomic arrangement within the monoclinic C2/m phase of selenium. Electron-phonon coupling calculations indicate that the super-conductivity observed in this material, akin to that in Tellurium, is realized via a phase transition. Furthermore, the superconducting critical temperature (Tc) displays a con-sistent rise as the material experiences high-pressure phase transitions from C2/m to R3(_)m and then to Im3(_)m, achieving a maximum Tc of 13.06 K in the Im3(_)m phase at 97.5 GPa. Our findings illuminate the path towards a deeper comprehension of the high-pressure structure and physics of selenium, prompting the need for innovative experi-mental and theoretical research.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"16 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142968512","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}
Hai-Bo Li, Xiu-Neng Song, Chuankui Wang, Weijie Hua, Yong Ma
Fluorinated graphdiyne (F-GDY) materials exhibit exceptional performance in various applications, such as luminescent devices, electron transport, and energy conversion. Although F-GDY has been successfully synthesized, there is a lack of comprehensive identification of fluorinated configurations, either by theory or experiment. In this work, we investigated seven representative F-GDY configurations with low dopant concentrations and simulated their carbon and fluorine 1s X-ray photoelectron spectroscopy (XPS) and carbon 1s near-edge X-ray absorption fine-structure (NEXAFS) spectra. The goal was to establish the structure-spectroscopy relation for these materials. The simulated XPS spectra closely match the experimental data, providing sensitive identifications of certain fluorinated structures, although challenges still persist in distinguishing a few similar configurations. In contrast, the NEXAFS spectra, generated by three non-equivalent carbon atoms at the K-edges, offer more detailed information and are more sensitive for identifying all different F-GDY structures. Our theoretical study provides valuable insights for future experimental identification of F-GDY structures. These findings underscore the utility of computational X-ray spectroscopy in advancing the understanding and development of novel carbon-based materials.
{"title":"Towards sensitive identification of fluorinated graphdiyne configurations by computational X-ray spectroscopy","authors":"Hai-Bo Li, Xiu-Neng Song, Chuankui Wang, Weijie Hua, Yong Ma","doi":"10.1039/d4cp04723k","DOIUrl":"https://doi.org/10.1039/d4cp04723k","url":null,"abstract":"Fluorinated graphdiyne (F-GDY) materials exhibit exceptional performance in various applications, such as luminescent devices, electron transport, and energy conversion. Although F-GDY has been successfully synthesized, there is a lack of comprehensive identification of fluorinated configurations, either by theory or experiment. In this work, we investigated seven representative F-GDY configurations with low dopant concentrations and simulated their carbon and fluorine 1s X-ray photoelectron spectroscopy (XPS) and carbon 1s near-edge X-ray absorption fine-structure (NEXAFS) spectra. The goal was to establish the structure-spectroscopy relation for these materials. The simulated XPS spectra closely match the experimental data, providing sensitive identifications of certain fluorinated structures, although challenges still persist in distinguishing a few similar configurations. In contrast, the NEXAFS spectra, generated by three non-equivalent carbon atoms at the K-edges, offer more detailed information and are more sensitive for identifying all different F-GDY structures. Our theoretical study provides valuable insights for future experimental identification of F-GDY structures. These findings underscore the utility of computational X-ray spectroscopy in advancing the understanding and development of novel carbon-based materials.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"84 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939512","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}
Energetic materials often possess different polymorphs that exhibit distinguishable performances. As a typical energetic material, hexanitrohexaazaisowurtzitane (CL-20 or HNIW) is one of the most powerful explosives nowadays. Phase transition of CL-20 induced by ubiquitous water vapor leading to an increase in sensitivity and a decrease in energy level is a key bottleneck that limiting the widespread application of CL-20-based explosives. Herein, solid-solid phase transition behavior of CL-20 induced by water vapor and the relating mechanism has been investigated. The results show that CL-20 undergoes an irreversible ε to α phase transition at an initial temperature of 104 °C in the presence of water vapor, much lower than that induced by thermal stimulation merely. According to XRD results and phase transition kinetics analysis, a four-parameter model is established to describe the phase transition process as a function of time. Theoretical calculations further support the promoting effect of water molecule on the phase transition. Based on experimental and theoretical results, possible mechanism of steam-induced solid-solid phase transition of CL-20 is put forward. This work will provide a theoretical basis for the reliability design of CL-20-based energetic materials, and also for the study on polymorphic transition inhibition of organic crystals to obtain the preferred phase.
{"title":"Mechanism investigation on solid-solid phase transition of CL-20 induced by water vapor","authors":"Ya Guo, Xuetong Cai, Fangbao Jiao, Zhicheng Guo, Qi Huang, Qi Zhang","doi":"10.1039/d4cp04494k","DOIUrl":"https://doi.org/10.1039/d4cp04494k","url":null,"abstract":"Energetic materials often possess different polymorphs that exhibit distinguishable performances. As a typical energetic material, hexanitrohexaazaisowurtzitane (CL-20 or HNIW) is one of the most powerful explosives nowadays. Phase transition of CL-20 induced by ubiquitous water vapor leading to an increase in sensitivity and a decrease in energy level is a key bottleneck that limiting the widespread application of CL-20-based explosives. Herein, solid-solid phase transition behavior of CL-20 induced by water vapor and the relating mechanism has been investigated. The results show that CL-20 undergoes an irreversible <em>ε</em> to <em>α</em> phase transition at an initial temperature of 104 °C in the presence of water vapor, much lower than that induced by thermal stimulation merely. According to XRD results and phase transition kinetics analysis, a four-parameter model is established to describe the phase transition process as a function of time. Theoretical calculations further support the promoting effect of water molecule on the phase transition. Based on experimental and theoretical results, possible mechanism of steam-induced solid-solid phase transition of CL-20 is put forward. This work will provide a theoretical basis for the reliability design of CL-20-based energetic materials, and also for the study on polymorphic transition inhibition of organic crystals to obtain the preferred phase.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"6 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939513","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}
Kun Hu, Yunpeng Yao, Zongli Hu, Lipengan Ye, Bin Tang, Wei Su
Driven by the pressing demand for integration and miniaturization within the terahertz (THz) spectrum, this research introduces an innovative approach to construct chiral structures using dichroicity as the target function. This initiative aims to tackle the prevalent issues of single-functionality, narrow application scope, and intricate design in conventional metasurfaces. The proposed multifunctional tunable metasurface employs a graphene-metal hybrid structure to address the critical constraints found in existing designs. When circularly polarized light is incident, the metasurface exhibits broadband circular dichroism (CD) function, generating CD intensities greater than 0.5 at 3.44-6.0 THz, and polarization switching function at 3.43-6.17 THz. When linearly polarized light is incident, the proposed design exhibits a broadband linear dichroism (LD) function, producing LD intensities greater than 0.5 at 2.25-5.65 THz and a polarization conversion function at 3.32-6.05 THz. Its broad bandwidth ensures that each function is competitive and effective. A noteworthy feature is the capability to adjust the graphene's chemical potential and the state of the incident light to finely calibrate the intensity of each functional aspect. This innovation makes the proposed multifunctional metasurface a significant reference for the development of chiral photodetectors, CD supermirrors, smart switches, and polarization digital imaging systems within the THz range.
{"title":"Design of graphene-based chiral trifunctional tunable terahertz metasurface","authors":"Kun Hu, Yunpeng Yao, Zongli Hu, Lipengan Ye, Bin Tang, Wei Su","doi":"10.1039/d4cp04423a","DOIUrl":"https://doi.org/10.1039/d4cp04423a","url":null,"abstract":"Driven by the pressing demand for integration and miniaturization within the terahertz (THz) spectrum, this research introduces an innovative approach to construct chiral structures using dichroicity as the target function. This initiative aims to tackle the prevalent issues of single-functionality, narrow application scope, and intricate design in conventional metasurfaces. The proposed multifunctional tunable metasurface employs a graphene-metal hybrid structure to address the critical constraints found in existing designs. When circularly polarized light is incident, the metasurface exhibits broadband circular dichroism (CD) function, generating CD intensities greater than 0.5 at 3.44-6.0 THz, and polarization switching function at 3.43-6.17 THz. When linearly polarized light is incident, the proposed design exhibits a broadband linear dichroism (LD) function, producing LD intensities greater than 0.5 at 2.25-5.65 THz and a polarization conversion function at 3.32-6.05 THz. Its broad bandwidth ensures that each function is competitive and effective. A noteworthy feature is the capability to adjust the graphene's chemical potential and the state of the incident light to finely calibrate the intensity of each functional aspect. This innovation makes the proposed multifunctional metasurface a significant reference for the development of chiral photodetectors, CD supermirrors, smart switches, and polarization digital imaging systems within the THz range.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"66 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936926","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}
Pressure-dependent reactions on the N2H3 potential energy surface (PES) are studied at the CCSDT(Q)/aug-cc-pVTZ level of theory. This work extends the N2H3 PES relative to previous literature studies by adding another isomer, NH3N, and additional bimolecular channels adjacent to the new isomer, NNH + H2, and H2NN + H. Theoretical predictions are made for the rate coefficients of all path and well-skipping pressure-dependent reactions. The theoretical analyses employ a combination of ab-initio transition state theory and master equation simulations. Pressure-dependent rate coefficients are computed for all reactions in the network. The dominant products of NH2 + NH(T) recombination are N2H2 + H, and at high pressures and low temperatures N2H3 formation becomes important. Collisions of H2NN + H on this surface yield mainly N2H2 + H as well. Important secondary reactions are H2NN + H <=> NNH + H2 at high temperatures and all examined pressures and H2NN + H <=> N2H3 at low temperatures and high pressures. None of these three reactions were considered by previous NH3 oxidation models with pressure-dependent rate coefficients. The rate coefficients obtained here should be useful in modeling ammonia, hydrazine, and hydrazine derivatives in various combustion environments.
{"title":"Pressure-Dependent Kinetic Analysis of the N2H3 Potential Energy Surface","authors":"Michal Keslin, Kfir Kaplan, Alon Grinberg Dana","doi":"10.1039/d4cp03837a","DOIUrl":"https://doi.org/10.1039/d4cp03837a","url":null,"abstract":"Pressure-dependent reactions on the N2H3 potential energy surface (PES) are studied at the CCSDT(Q)/aug-cc-pVTZ level of theory. This work extends the N2H3 PES relative to previous literature studies by adding another isomer, NH3N, and additional bimolecular channels adjacent to the new isomer, NNH + H2, and H2NN + H. Theoretical predictions are made for the rate coefficients of all path and well-skipping pressure-dependent reactions. The theoretical analyses employ a combination of ab-initio transition state theory and master equation simulations. Pressure-dependent rate coefficients are computed for all reactions in the network. The dominant products of NH2 + NH(T) recombination are N2H2 + H, and at high pressures and low temperatures N2H3 formation becomes important. Collisions of H2NN + H on this surface yield mainly N2H2 + H as well. Important secondary reactions are H2NN + H <=> NNH + H2 at high temperatures and all examined pressures and H2NN + H <=> N2H3 at low temperatures and high pressures. None of these three reactions were considered by previous NH3 oxidation models with pressure-dependent rate coefficients. The rate coefficients obtained here should be useful in modeling ammonia, hydrazine, and hydrazine derivatives in various combustion environments.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"35 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936923","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}
Yaroslav Nikiforov, Victoria A. Danilovsky, Natalia Baklanova
This work investigates the solid-state reaction between iridium and zirconium carbide, resulting in the formation of carbon and ZrIr3—an intermetallic compound of great interest for modern high-temperature materials science. We have found a transition of kinetic regimes in this reaction: from linear kinetics (when the chemical reaction is a limiting stage) at 1500 and 1550○C to `non-parabolic kinetics' at 1600○ C. Non-parabolic kinetics is characterized by thickness of a product layer being proportional to a power of time less than 1/2. The nature of non-parabolic kinetics was still an open question, which motivated us to develop a model of this kinetic regime. The proposed model accounts for the grain growth in the product phase and how it leads to the time dependence of the interdiffusion coefficient. We have obtained a complete analytic solution for this model and an equation that connects the grain-growth exponent and the power-law exponent of non-parabolic kinetics. The measurements of the thickness of the product layer and the average grain size of the intermetallic phase confirm the results of the theoretical solution.
{"title":"How grain structure evolution affects kinetics of a solid-state reaction: a case of interaction between iridium and zirconium carbide","authors":"Yaroslav Nikiforov, Victoria A. Danilovsky, Natalia Baklanova","doi":"10.1039/d4cp04302b","DOIUrl":"https://doi.org/10.1039/d4cp04302b","url":null,"abstract":"This work investigates the solid-state reaction between iridium and zirconium carbide, resulting in the formation of carbon and ZrIr<small><sub>3</sub></small>—an intermetallic compound of great interest for modern high-temperature materials science. We have found a transition of kinetic regimes in this reaction: from linear kinetics (when the chemical reaction is a limiting stage) at 1500 and 1550<small><sup>○</sup></small>C to `non-parabolic kinetics' at 1600<small><sup>○</sup></small> C. Non-parabolic kinetics is characterized by thickness of a product layer being proportional to a power of time less than 1/2. The nature of non-parabolic kinetics was still an open question, which motivated us to develop a model of this kinetic regime. The proposed model accounts for the grain growth in the product phase and how it leads to the time dependence of the interdiffusion coefficient. We have obtained a complete analytic solution for this model and an equation that connects the grain-growth exponent and the power-law exponent of non-parabolic kinetics. The measurements of the thickness of the product layer and the average grain size of the intermetallic phase confirm the results of the theoretical solution.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"28 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936924","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}
Naphthalenediimide (NDI)-based donor–acceptor co-polymers with tunable electronic, optical, mechanical, and transport properties have shown immense potential as n-type conducting polymers in organic (opto)electronics. During the operation, the polymers undergo reduction at different charged states, which alters their (opto)electronic properties mainly due to the formation of the quasiparticles, polaron/bipolaron. The theoretical study based on quantum mechanical calculations can provide us with a detailed understanding of their (opto)electronic properties, which is missing to a great extent. To date, a theoretical understanding of how these properties vary with reduction levels for NDI-based polymers is completely missing. Herein, the evolution of the electronic structure and optical properties of the naphthalenediimide dithienylvinylene (NDI-TVT) polymer with varying reduction levels (Cred) is studied using density functional theory and time-dependent density functional theory, respectively, in the gaseous phase and solvent phase. We have envisaged that at lower reduction levels, Cred ≤ 100% (i.e., up to one negative charge per NDI moiety), only radical anions, i.e., polarons, are formed. The bipolarons are observed to be formed only at higher reduction levels, Cred > 100%. We note the coexistence of polarons and bipolarons for the intermediate reduction levels (100% < Cred < 200%). Finally, at 200% reduction levels, the presence of two electrons per NDI unit leads to the completely spin-resolved bipolaronic state formation, where one bipolaron is localized at every NDI unit. This aforementioned evolution of polarons and bipolarons with varying reduction levels is also prominently reflected in the calculated UV-vis-NIR absorption spectra. The detailed theoretical insights gained from the evolution of the (opto)electronic properties of NDI-TVT with reduction levels due to the formation of polaronic/bipolaronic states can guide the systematic design of n-type NDI-TVT-based (opto)electronic devices and in their advancement.
{"title":"Evolution of electronic structure and optical properties of naphthalenediimide dithienylvinylene (NDI-TVT) polymer as a function of reduction level: a density functional theory study","authors":"Sushri Soumya Jena, Mohit Garg, Sarbani Ghosh","doi":"10.1039/d4cp02770a","DOIUrl":"https://doi.org/10.1039/d4cp02770a","url":null,"abstract":"Naphthalenediimide (NDI)-based donor–acceptor co-polymers with tunable electronic, optical, mechanical, and transport properties have shown immense potential as n-type conducting polymers in organic (opto)electronics. During the operation, the polymers undergo reduction at different charged states, which alters their (opto)electronic properties mainly due to the formation of the quasiparticles, polaron/bipolaron. The theoretical study based on quantum mechanical calculations can provide us with a detailed understanding of their (opto)electronic properties, which is missing to a great extent. To date, a theoretical understanding of how these properties vary with reduction levels for NDI-based polymers is completely missing. Herein, the evolution of the electronic structure and optical properties of the naphthalenediimide dithienylvinylene (NDI-TVT) polymer with varying reduction levels (<em>C</em><small><sub>red</sub></small>) is studied using density functional theory and time-dependent density functional theory, respectively, in the gaseous phase and solvent phase. We have envisaged that at lower reduction levels, <em>C</em><small><sub>red</sub></small> ≤ 100% (<em>i.e.</em>, up to one negative charge per NDI moiety), only radical anions, <em>i.e.</em>, polarons, are formed. The bipolarons are observed to be formed only at higher reduction levels, <em>C</em><small><sub>red</sub></small> > 100%. We note the coexistence of polarons and bipolarons for the intermediate reduction levels (100% < <em>C</em><small><sub>red</sub></small> < 200%). Finally, at 200% reduction levels, the presence of two electrons per NDI unit leads to the completely spin-resolved bipolaronic state formation, where one bipolaron is localized at every NDI unit. This aforementioned evolution of polarons and bipolarons with varying reduction levels is also prominently reflected in the calculated UV-vis-NIR absorption spectra. The detailed theoretical insights gained from the evolution of the (opto)electronic properties of NDI-TVT with reduction levels due to the formation of polaronic/bipolaronic states can guide the systematic design of n-type NDI-TVT-based (opto)electronic devices and in their advancement.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"23 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936925","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}
One of the most subtle steps in the single-molecule approach to the flux through the membrane channel, which uses the one-dimensional Smoluchowski equation, is to describe the molecule's “behavior” at the contacts between the channel openings and the bulk. Earlier, to handle this issue, we introduced the so-called “radiation boundary conditions” that account for the interplay between the two types of trajectories of the molecules starting at the openings, specifically, the ones that eventually return to the channel and the ones that escape to infinity. The latter trajectories represent the true translocation events on the condition that initially the molecule entered the channel from the opposite side. Here, we demonstrate that the single molecule approach based on the one-dimensional Smoluchowski equation with radiation boundary conditions leads to the same expression for the flux through the channel as the conventional approach based on the linear transport theory.
{"title":"Flux through membrane channel: linear transport vs. single-molecule approaches","authors":"Alexander M. Berezhkovskii, Sergey M. Bezrukov","doi":"10.1039/d4cp04109g","DOIUrl":"https://doi.org/10.1039/d4cp04109g","url":null,"abstract":"One of the most subtle steps in the single-molecule approach to the flux through the membrane channel, which uses the one-dimensional Smoluchowski equation, is to describe the molecule's “behavior” at the contacts between the channel openings and the bulk. Earlier, to handle this issue, we introduced the so-called “radiation boundary conditions” that account for the interplay between the two types of trajectories of the molecules starting at the openings, specifically, the ones that eventually return to the channel and the ones that escape to infinity. The latter trajectories represent the true translocation events on the condition that initially the molecule entered the channel from the opposite side. Here, we demonstrate that the single molecule approach based on the one-dimensional Smoluchowski equation with radiation boundary conditions leads to the same expression for the flux through the channel as the conventional approach based on the linear transport theory.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"1 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936922","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}
Correction for ‘The effect of particle size on the optical and electronic properties of hydrogenated silicon nanoparticles’ by Eimear Madden et al., Phys. Chem. Chem. Phys., 2024, 26, 11695–11707, https://doi.org/10.1039/D4CP00119B.
{"title":"Correction: The effect of particle size on the optical and electronic properties of hydrogenated silicon nanoparticles","authors":"Eimear Madden, Martijn A. Zwijnenburg","doi":"10.1039/d4cp90219j","DOIUrl":"https://doi.org/10.1039/d4cp90219j","url":null,"abstract":"Correction for ‘The effect of particle size on the optical and electronic properties of hydrogenated silicon nanoparticles’ by Eimear Madden <em>et al.</em>, <em>Phys. Chem. Chem. Phys.</em>, 2024, <strong>26</strong>, 11695–11707, https://doi.org/10.1039/D4CP00119B.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"14 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936921","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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