Zixin Zhou, Min Zhou, Xiaobin Liao, Mengjun Zhou, Xiaolin Liu, Qian Liu, Yan Zhao
Hydrazine oxidation reaction (HzOR) provides a sustainable alternative to the sluggish oxygen evolution reaction (OER), with a low theoretical thermodynamic potential (−0.33 V vs. RHE). However, developing efficient non-precious-metal catalysts for HzOR remains challenging. Here, we employed density functional theory (DFT) simulations to systematically investigate the mechanism of transition metal atoms doping (Au, Cr, Fe, Mn, Mo, Ni, Pd, Pt) to boost the N-H bond cleavage in HzOR. Among the studied dopants, Cr and Mn exhibit exceptional catalytic activity, achieving ultralow ΔG for RDS of −0.02 eV (CoP-Cr) and 0.02 eV (CoP-Mn), significantly lower than the high-coordination cobalt sites on undoped CoP (0.11 eV). CoP-Cr aligns with descriptor-driven optimization, while CoP-Mn operates via dopant-induced charge redistribution. Furthermore, we identified the adsorption free energy of N–NH2 (ΔGad-N2H2-1) as a robust descriptor for catalytic activity in the reaction pathway involving distal configuration, showing strong correlations with ΔG of RDS. This work proposed a dual design strategy—descriptor-driven optimization (CoP-Cr) and charge-redistribution enhancement (CoP-Mn)—as a roadmap for developing earth-abundant, high-performance catalysts. These insights pave the way for advancing sustainable hydrogen production and environmental remediation technologies.
{"title":"Transition Metal-Doped Cobalt Phosphide for Efficient Hydrazine Oxidation: A Density Functional Theory Study","authors":"Zixin Zhou, Min Zhou, Xiaobin Liao, Mengjun Zhou, Xiaolin Liu, Qian Liu, Yan Zhao","doi":"10.1039/d5cp01150g","DOIUrl":"https://doi.org/10.1039/d5cp01150g","url":null,"abstract":"Hydrazine oxidation reaction (HzOR) provides a sustainable alternative to the sluggish oxygen evolution reaction (OER), with a low theoretical thermodynamic potential (−0.33 V vs. RHE). However, developing efficient non-precious-metal catalysts for HzOR remains challenging. Here, we employed density functional theory (DFT) simulations to systematically investigate the mechanism of transition metal atoms doping (Au, Cr, Fe, Mn, Mo, Ni, Pd, Pt) to boost the N-H bond cleavage in HzOR. Among the studied dopants, Cr and Mn exhibit exceptional catalytic activity, achieving ultralow ΔG for RDS of −0.02 eV (CoP-Cr) and 0.02 eV (CoP-Mn), significantly lower than the high-coordination cobalt sites on undoped CoP (0.11 eV). CoP-Cr aligns with descriptor-driven optimization, while CoP-Mn operates via dopant-induced charge redistribution. Furthermore, we identified the adsorption free energy of N–NH<small><sub>2</sub></small> (ΔG<small><sub>ad-N2H2-1</sub></small>) as a robust descriptor for catalytic activity in the reaction pathway involving distal configuration, showing strong correlations with ΔG of RDS. This work proposed a dual design strategy—descriptor-driven optimization (CoP-Cr) and charge-redistribution enhancement (CoP-Mn)—as a roadmap for developing earth-abundant, high-performance catalysts. These insights pave the way for advancing sustainable hydrogen production and environmental remediation technologies.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"90 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832143","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}
We present an algorithm for accelerating the search of a molecule's adsorption sites based on global optimization of surface adsorbate geometries. Our approach uses a machine-learning interatomic potential (moment tensor potential) to approximate the potential energy surface and an active learning algorithm for the automatic construction of an optimal training dataset. To validate our methodology, we compare the results across various well-known catalytic systems with surfaces of different crystallographic orientations and adsorbate geometries, including CO/Pd(111), NO/Pd(100), NH3/Cu(100), C6H6/Ag(111), and CH2CO/Rh(211). In all the cases, we observed an agreement of our results with the literature.
{"title":"Accelerating the global search of adsorbate molecule positions using machine-learning interatomic potentials with active learning","authors":"Olga Klimanova, Nikita Rybin, Alexander Shapeev","doi":"10.1039/d5cp00532a","DOIUrl":"https://doi.org/10.1039/d5cp00532a","url":null,"abstract":"We present an algorithm for accelerating the search of a molecule's adsorption sites based on global optimization of surface adsorbate geometries. Our approach uses a machine-learning interatomic potential (moment tensor potential) to approximate the potential energy surface and an active learning algorithm for the automatic construction of an optimal training dataset. To validate our methodology, we compare the results across various well-known catalytic systems with surfaces of different crystallographic orientations and adsorbate geometries, including CO/Pd(111), NO/Pd(100), NH<small><sub>3</sub></small>/Cu(100), C<small><sub>6</sub></small>H<small><sub>6</sub></small>/Ag(111), and CH<small><sub>2</sub></small>CO/Rh(211). In all the cases, we observed an agreement of our results with the literature.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"74 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832381","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}
Amino radical plays a central role in the pyrolysis and oxidation of ammonia. The practical utilization of pure ammonia as a fuel still faces several challenges. The dual-fuel combustion strategy, which involves blending low-reactivity NH3 with high-reactivity fuels, can effectively address these issues. In this work, we theoretically investigate the amino cross-reaction kinetics of the three saturated methyl esters including methyl formate (MF), methyl acetate (MA) and methyl propanoate (MP) (i.e., CnH2n + 1C(=O)OCH3, (n = 0, 1, 2)) and the three unsaturated methyl esters methyl acrylate (MAe), methyl butenoate (MB) and methyl crotonate (MC) (i.e., CmH2m - 1C(=O)OCH3, (m = 2, 3)). Comparing the energy barriers and reaction energies of these reactions calculated at two high-level electronic structure methods CCSD(T)/cc-pVxZ (x = T, Q) for MF, MA and MAe and CCSD(T)-F12/cc-pVTZ-F12 for MP, the M05-2X/jun-cc-pVTZ method has been selected due to the best performance with mean unsigned deviations (MUDs) from the CCSD(T) calculations of 0.23 kcal mol-1 (MF), 0.59 kcal mol-1 (MA), 0.55 kcal mol-1 (MP) and 0.38 kcal mol-1 (MAe). The rate constants of these reactions are calculated by using the multi-structural canonical variational transition state theory (MS-CVT/SCT) including the multi-dimensional small-curvature tunneling approximation, and the multiple-structure and torsional potential anharmonic effects at 500–2000 K. Our results are in good agreement with the available literature results and it can be found that the effect of different abstracting free radicals on the rate constants is greater than the effect of different fuels. Furthermore, based on our calculations, a combustion kinetic model has been proposed to elucidate the combustion mechanism of MAe/MP + ammonia mixtures. Kinetic analysis indicates that MAe generates reactive radicals in the initial stage due to its high reactivity, which disrupts the system and accelerates the consumption of NH3 through H-abstraction reactions. In the presence of MP, the important intermediate N2H2 is more likely to form N2H3 rather than NNH. This contributes to a deeper understanding of the combustion mechanism of ammonia/fatty acid methyl esters.
{"title":"Implication of amino cross-reactions on the ignition characteristics of ammonia-blended typical small saturated and unsaturated fatty acid methyl esters","authors":"Haixing Deng, Sihao Wang, Li Fu, Hongbo Ning","doi":"10.1039/d5cp00958h","DOIUrl":"https://doi.org/10.1039/d5cp00958h","url":null,"abstract":"Amino radical plays a central role in the pyrolysis and oxidation of ammonia. The practical utilization of pure ammonia as a fuel still faces several challenges. The dual-fuel combustion strategy, which involves blending low-reactivity NH3 with high-reactivity fuels, can effectively address these issues. In this work, we theoretically investigate the amino cross-reaction kinetics of the three saturated methyl esters including methyl formate (MF), methyl acetate (MA) and methyl propanoate (MP) (i.e., CnH2n + 1C(=O)OCH3, (n = 0, 1, 2)) and the three unsaturated methyl esters methyl acrylate (MAe), methyl butenoate (MB) and methyl crotonate (MC) (i.e., CmH2m - 1C(=O)OCH3, (m = 2, 3)). Comparing the energy barriers and reaction energies of these reactions calculated at two high-level electronic structure methods CCSD(T)/cc-pVxZ (x = T, Q) for MF, MA and MAe and CCSD(T)-F12/cc-pVTZ-F12 for MP, the M05-2X/jun-cc-pVTZ method has been selected due to the best performance with mean unsigned deviations (MUDs) from the CCSD(T) calculations of 0.23 kcal mol-1 (MF), 0.59 kcal mol-1 (MA), 0.55 kcal mol-1 (MP) and 0.38 kcal mol-1 (MAe). The rate constants of these reactions are calculated by using the multi-structural canonical variational transition state theory (MS-CVT/SCT) including the multi-dimensional small-curvature tunneling approximation, and the multiple-structure and torsional potential anharmonic effects at 500–2000 K. Our results are in good agreement with the available literature results and it can be found that the effect of different abstracting free radicals on the rate constants is greater than the effect of different fuels. Furthermore, based on our calculations, a combustion kinetic model has been proposed to elucidate the combustion mechanism of MAe/MP + ammonia mixtures. Kinetic analysis indicates that MAe generates reactive radicals in the initial stage due to its high reactivity, which disrupts the system and accelerates the consumption of NH3 through H-abstraction reactions. In the presence of MP, the important intermediate N2H2 is more likely to form N2H3 rather than NNH. This contributes to a deeper understanding of the combustion mechanism of ammonia/fatty acid methyl esters.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"17 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832141","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}
Valentin Schwaab, Fabian Düll, Philipp Bachmann, Felix Hemauer, Hans-Peter Steinrück, Christian Papp
We prepared a Pt-terminated PtRu near-surface alloy with a lateral concentration gradient on Pt(111). The near-surface alloy is exposed to CO at 100 K or O2 at 600 K and subsequently investigated using synchrotron-based high-resolution X-ray photoelectron spectroscopy. By moving the sample laterally under the focused X-ray beam (spot size ~0.05 mm), we were able to study locally different alloy compositions under identical measurement conditions. With increasing subsurface Ru concentration, we observe a gradual decrease in the CO occupancy of Pt bridge sites, while the amount of on-top adsorbed CO remains constant over the investigated compositional range. Oxidation of the alloy reveals a clear increase in the fraction of oxidized Ru atoms (the RuOx:Ru ratio) with increasing Ru content.
{"title":"Effect of the Ru concentration on the CO tolerance and the oxidizability of a composition spread PtRu/Pt(111) near-surface alloy","authors":"Valentin Schwaab, Fabian Düll, Philipp Bachmann, Felix Hemauer, Hans-Peter Steinrück, Christian Papp","doi":"10.1039/d5cp00295h","DOIUrl":"https://doi.org/10.1039/d5cp00295h","url":null,"abstract":"We prepared a Pt-terminated PtRu near-surface alloy with a lateral concentration gradient on Pt(111). The near-surface alloy is exposed to CO at 100 K or O2 at 600 K and subsequently investigated using synchrotron-based high-resolution X-ray photoelectron spectroscopy. By moving the sample laterally under the focused X-ray beam (spot size ~0.05 mm), we were able to study locally different alloy compositions under identical measurement conditions. With increasing subsurface Ru concentration, we observe a gradual decrease in the CO occupancy of Pt bridge sites, while the amount of on-top adsorbed CO remains constant over the investigated compositional range. Oxidation of the alloy reveals a clear increase in the fraction of oxidized Ru atoms (the RuOx:Ru ratio) with increasing Ru content.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"20 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832144","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}
D. C. Alders, D. J. Cette, R. J. M. Konings, A. L. Smith
Correction for ‘Experimental investigation and thermodynamic modelling assessment of the AECl2–NdCl3 (AE = Sr, Ba) systems’ by D. C. Alders et al., Phys. Chem. Chem. Phys., 2024, 26, 24041–24057, https://doi.org/10.1039/D4CP01784F.
{"title":"Correction: Experimental investigation and thermodynamic modelling assessment of the AECl2–NdCl3 (AE = Sr, Ba) systems","authors":"D. C. Alders, D. J. Cette, R. J. M. Konings, A. L. Smith","doi":"10.1039/d5cp90070k","DOIUrl":"https://doi.org/10.1039/d5cp90070k","url":null,"abstract":"Correction for ‘Experimental investigation and thermodynamic modelling assessment of the AECl<small><sub>2</sub></small>–NdCl<small><sub>3</sub></small> (AE = Sr, Ba) systems’ by D. C. Alders <em>et al.</em>, <em>Phys. Chem. Chem. Phys.</em>, 2024, <strong>26</strong>, 24041–24057, https://doi.org/10.1039/D4CP01784F.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"26 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832369","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}
Co(II) was doped into the diamagnetic one-dimensional framework of bis(dimethylglyoximato) Ni(II) and Pd(II) complex [Ni/PdII(Hdmg)2] (Hdmg = dimethylglyoximate anion) (hereafter referred to as Co@Ni and Co@Pd samples) to study magnetic properties as a potential spin qubit. The previous report of electron paramagnetic resonance (EPR) spectroscopy of this compound prepared using the same doping strategy in the Ni matrix observed a spectrum assigned to S = 1/2 Co(II) with gx = 2.58, gy = 2.26 gx = 1.98. The relatively large gx value, compared to those typically observed in [Co(Hdmg)2Bx] complexes (B = Lewis base ligand, x = 1 or 2), which fall within the ranges gx = 2.1 - 2.4, gy = 2.0 - 2.2 and gz ≈ 2.01, led to the interpretation of this species as Co(Hdmg)2 with an extremely axial interaction. However, our EPR analysis, combined with SQUID (superconducting quantum interference device) and XANES (X-ray absorption near-edge structure) analysis, revealed that the previously identified species are μ-O bridged dimers: [Co(Hdmg)(μ-Hdmg)]2 and [Co(Hdmg)(μ-Hdmg)][Ni/Pd(Hdmg)(μ-Hdmg)]. Furthermore, our liquid-helium temperature EPR spectra revealed a Co species with much greater axial g anisotropy (gx = 4.75 gy,z ≈ 0.75 for Co@Ni and gx = 4.2 gy,z ≈ 1.33 for Co@Pd). We assign this species to the truly planar Co(Hdmg)2 with negligibly weak axial interaction, which might have been overlooked in the previous EPR studies.
{"title":"Revisiting cobaloxime(II) chemistry and clearing misconceptions of cobaloxime(II) in diamagnetic Ni(II) and Pd(II) matrix by comprehensive magnetic measurements","authors":"Yukina Suzuki, Mirosław Arczyński, Masanori Wakizaka, Hisaaki Tanaka, Ryuta Ishikawa, Takefumi Yoshida, Takeshi Yamane, Kazunobu Sato, Ryota Sakamoto, Masahiro Yamashita","doi":"10.1039/d5cp00629e","DOIUrl":"https://doi.org/10.1039/d5cp00629e","url":null,"abstract":"Co(II) was doped into the diamagnetic one-dimensional framework of bis(dimethylglyoximato) Ni(II) and Pd(II) complex [Ni/Pd<small><sup>II</sup></small>(Hdmg)<small><sub>2</sub></small>] (Hdmg = dimethylglyoximate anion) (hereafter referred to as Co@Ni and Co@Pd samples) to study magnetic properties as a potential spin qubit. The previous report of electron paramagnetic resonance (EPR) spectroscopy of this compound prepared using the same doping strategy in the Ni matrix observed a spectrum assigned to <em>S</em> = 1/2 Co(II) with <em>g<small><sub>x</sub></small></em> = 2.58, <em>g<small><sub>y</sub></small></em> = 2.26 <em>g<small><sub>x</sub></small></em> = 1.98. The relatively large <em>g<small><sub>x</sub></small></em> value, compared to those typically observed in [Co(Hdmg)2Bx] complexes (B = Lewis base ligand, x = 1 or 2), which fall within the ranges <em>g<small><sub>x</sub></small></em> = 2.1 - 2.4, <em>g<small><sub>y</sub></small></em> = 2.0 - 2.2 and <em>g<small><sub>z</sub></small></em> ≈ 2.01, led to the interpretation of this species as Co(Hdmg)2 with an extremely axial interaction. However, our EPR analysis, combined with SQUID (superconducting quantum interference device) and XANES (X-ray absorption near-edge structure) analysis, revealed that the previously identified species are μ-O bridged dimers: [Co(Hdmg)(μ-Hdmg)]2 and [Co(Hdmg)(μ-Hdmg)][Ni/Pd(Hdmg)(μ-Hdmg)]. Furthermore, our liquid-helium temperature EPR spectra revealed a Co species with much greater axial <em>g</em> anisotropy (<em>g<small><sub>x</sub></small></em> = 4.75 <em>g<small><sub>y,z</sub></small></em> ≈ 0.75 for Co@Ni and <em>g<small><sub>x</sub></small></em> = 4.2 <em>g<small><sub>y,z</sub></small></em> ≈ 1.33 for Co@Pd). We assign this species to the truly planar Co(Hdmg)<small><sub>2</sub></small> with negligibly weak axial interaction, which might have been overlooked in the previous EPR studies.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"40 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832140","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}
The microwave spectrum of the non-rigid trans-cyclohexanediamine (C6H10(NH2)2) is investigated. It displays a large amplitude interconversion motion during which both amino groups are rotated through 117 degrees leading to tunneling splittings on the order of 21 MHz and line splittings on the order of 42 MHz for b- and c-type transitions. The tunneling is mediated by the quadrupole coupling hyperfine structure arising from both nitrogen atoms which leads to splittings on the same order of magnitude. The frequencies of the rotation-tunneling-hyperfine transitions are analyzed using a new theoretical model in which the large amplitude motion and the quadrupole coupling are treated simultaneously. Hyperfine matrix elements between (within) tunneling sublevels depend on the difference (sum) of the quadrupole coupling of the two nitrogen atoms. Using the theoretical formalism, 249 experimental frequencies are reproduced with an RMS value of 10 kHz, close to the experimental uncertainty. The spectroscopic parameters determined include usual rotational and distortion parameters; tunneling parameters describing the magnitude of the tunneling and its rotational dependence; and various components of the effective quadrupole coupling tensors.
{"title":"Hyperfine structure-tunneling coupling in trans-1,2-cyclohexanediamine revealed by rotational spectroscopy","authors":"Laurent Henri Coudert, Fan Xie, Melanie Schnell","doi":"10.1039/d5cp00586h","DOIUrl":"https://doi.org/10.1039/d5cp00586h","url":null,"abstract":"The microwave spectrum of the non-rigid trans-cyclohexanediamine (C6H10(NH2)2) is investigated. It displays a large amplitude interconversion motion during which both amino groups are rotated through 117 degrees leading to tunneling splittings on the order of 21 MHz and line splittings on the order of 42 MHz for b- and c-type transitions. The tunneling is mediated by the quadrupole coupling hyperfine structure arising from both nitrogen atoms which leads to splittings on the same order of magnitude. The frequencies of the rotation-tunneling-hyperfine transitions are analyzed using a new theoretical model in which the large amplitude motion and the quadrupole coupling are treated simultaneously. Hyperfine matrix elements between (within) tunneling sublevels depend on the difference (sum) of the quadrupole coupling of the two nitrogen atoms. Using the theoretical formalism, 249 experimental frequencies are reproduced with an RMS value of 10 kHz, close to the experimental uncertainty. The spectroscopic parameters determined include usual rotational and distortion parameters; tunneling parameters describing the magnitude of the tunneling and its rotational dependence; and various components of the effective quadrupole coupling tensors.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"38 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832138","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}
In this paper, we theoretically study the effects of twist and heterostrain on moiré excitons in the $MoSe_2/WSe_2$ heterobilayer. Using a continuum model, we analyze the band structures and wavefunction distributions of moiré excitons, photoluminescence spectra, and the hybridization between interlayer and intralayer moiré excitons. Our key findings reveal that, under the influence of twisting effect, moiré excitons flat bands emerge. Additionally, we observe that the bright states exhibit a linear and quadratic dependence on the twist angle. We predict the existence of a critical twist angle, $theta_c simeq 2^circ$, which distinguishes between localized and delocalized regimes. In contrast, the three-fold rotational symmetry breaking induced by heterostrain leads to significant tunability of the exciton band structure and the distribution of bright states. Moreover, exploring the strain magnitude and direction may enhance the brightness of moiré exciton bright states, emphasizing the importance of strain orientation in excitonic optical modulator applications. Furthermore, the combined effects of twist and strain result in a high degree of tunability in the hybridization between interlayer and intralayer excitons. Interestingly, under specific strain magnitudes and directions, such as normal compressive strain, we observe the emergence of a topological moiré exciton Chern insulator, featuring the protected edge modes. Our predictions may pave the way for exploring novel topological exciton phenomena and moiré exciton-correlated physics. They are particularly intriguing for potential device applications in the excitonic quantum anomalous Hall effect (EQAHE) enabled by the combined effects of strain and twist.
{"title":"Hybrid moiré excitons in strained heterobilayer of transition metal dichalcogenides","authors":"Houssem Eddine Hannachi, Sihem Jaziri","doi":"10.1039/d4cp04759a","DOIUrl":"https://doi.org/10.1039/d4cp04759a","url":null,"abstract":"In this paper, we theoretically study the effects of twist and heterostrain on moiré excitons in the $MoSe_2/WSe_2$ heterobilayer. Using a continuum model, we analyze the band structures and wavefunction distributions of moiré excitons, photoluminescence spectra, and the hybridization between interlayer and intralayer moiré excitons. Our key findings reveal that, under the influence of twisting effect, moiré excitons flat bands emerge. Additionally, we observe that the bright states exhibit a linear and quadratic dependence on the twist angle. We predict the existence of a critical twist angle, $theta_c simeq 2^circ$, which distinguishes between localized and delocalized regimes. In contrast, the three-fold rotational symmetry breaking induced by heterostrain leads to significant tunability of the exciton band structure and the distribution of bright states. Moreover, exploring the strain magnitude and direction may enhance the brightness of moiré exciton bright states, emphasizing the importance of strain orientation in excitonic optical modulator applications. Furthermore, the combined effects of twist and strain result in a high degree of tunability in the hybridization between interlayer and intralayer excitons. Interestingly, under specific strain magnitudes and directions, such as normal compressive strain, we observe the emergence of a topological moiré exciton Chern insulator, featuring the protected edge modes. Our predictions may pave the way for exploring novel topological exciton phenomena and moiré exciton-correlated physics. They are particularly intriguing for potential device applications in the excitonic quantum anomalous Hall effect (EQAHE) enabled by the combined effects of strain and twist.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"108 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143837450","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}
Lulu Zhou, Zhanhan Hu, Wei Shi, Yixiao Zhang, Yangyang Zhu, Yi Liao, Yachen Xu, Jialu Gu, Weixia Lan, Bin Wei
We investigated the degradation performance of organic light-emitting diodes (OLEDs) under different ultraviolet (UV) irradiation intensities and demonstrated that the stretched exponential decay (SED) model, applicable in electrical aging, is also suitable for describing the luminance-time curves in photoaging. In this way, OLED lifetime acquired at low UV illumination could be fitted with that obtained at high illumination. We also demonstrated how UV radiation affects the interface at ITO/hole transporting layer, which led to its degradation. This was elucidated through changes in the mobility of single-carrier devices and XPS characterization of the films before and after UV irradiation. These findings reveal the external behavior and internal mechanism of OLED in light aging, providing a reliable research direction for enhancing the stability of organic electronic devices.
{"title":"Research on the Influence of Ultraviolet Radiation on OLED and the Luminance Attenuation Model of Light Aging","authors":"Lulu Zhou, Zhanhan Hu, Wei Shi, Yixiao Zhang, Yangyang Zhu, Yi Liao, Yachen Xu, Jialu Gu, Weixia Lan, Bin Wei","doi":"10.1039/d5cp00664c","DOIUrl":"https://doi.org/10.1039/d5cp00664c","url":null,"abstract":"We investigated the degradation performance of organic light-emitting diodes (OLEDs) under different ultraviolet (UV) irradiation intensities and demonstrated that the stretched exponential decay (SED) model, applicable in electrical aging, is also suitable for describing the luminance-time curves in photoaging. In this way, OLED lifetime acquired at low UV illumination could be fitted with that obtained at high illumination. We also demonstrated how UV radiation affects the interface at ITO/hole transporting layer, which led to its degradation. This was elucidated through changes in the mobility of single-carrier devices and XPS characterization of the films before and after UV irradiation. These findings reveal the external behavior and internal mechanism of OLED in light aging, providing a reliable research direction for enhancing the stability of organic electronic devices.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"32 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832136","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}
Passive and active fillers loaded poly(ethylene oxide), PEO, based solid state polymer electrolytes (SPEs) are considered promising alternatives for currently used flammable liquid electrolytes in lithium metal batteries. The enhancement in ionic conductivity of PEO based composite electrolytes is attributed to the additional ion-conduction pathways available at the interphase region. Considering this aspect, in the present study, we have prepared dendritic fibrous nanosilica (DFNS) loaded PEO based polymer composite (PEO-DNFS) and electrolytes (PEO-Li, PEO-Li-DFNS) having (EO:Li = 20:1). DFNS has been chosen as filler due to its unique dendritic fibrous structure which is expected to create large interphase region in the composites. These composites and electrolytes were characterized using various techniques viz. powder X-ray diffraction (PXRD), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC) for determining the modifications in chemical bonding and thermal properties. Positron annihilation lifetime spectroscopy (PALS) and broadband dielectric spectroscopy (BDS) were employed to determine the modifications in the free volume structure/chain packing of PEO and ion conduction mechanism, respectively. The relative free volume was observed to increase with DFNS loading due to modifications in the chain packing. The higher number of free volume holes provide additional pathways for ionic diffusion leading to an enhancement in ionic conductivity. The role of relative free volume in ionic conductivity enhancement is further established through the strong coupling observed between ionic conduction and segmental relaxations of PEO electrolytes investigated using BDS.
{"title":"Correlations between free volume structure and ionic conductivity of poly (ethylene oxide) and dendritic fibrous nanosilica composite based electrolyte: An investigation using positron annihilation and broadband dielectric spectroscopy","authors":"Jaideep Mor, Kanaklata Pandey, Sandeep Kumar Sharma","doi":"10.1039/d4cp04826a","DOIUrl":"https://doi.org/10.1039/d4cp04826a","url":null,"abstract":"Passive and active fillers loaded poly(ethylene oxide), PEO, based solid state polymer electrolytes (SPEs) are considered promising alternatives for currently used flammable liquid electrolytes in lithium metal batteries. The enhancement in ionic conductivity of PEO based composite electrolytes is attributed to the additional ion-conduction pathways available at the interphase region. Considering this aspect, in the present study, we have prepared dendritic fibrous nanosilica (DFNS) loaded PEO based polymer composite (PEO-DNFS) and electrolytes (PEO-Li, PEO-Li-DFNS) having (EO:Li = 20:1). DFNS has been chosen as filler due to its unique dendritic fibrous structure which is expected to create large interphase region in the composites. These composites and electrolytes were characterized using various techniques viz. powder X-ray diffraction (PXRD), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC) for determining the modifications in chemical bonding and thermal properties. Positron annihilation lifetime spectroscopy (PALS) and broadband dielectric spectroscopy (BDS) were employed to determine the modifications in the free volume structure/chain packing of PEO and ion conduction mechanism, respectively. The relative free volume was observed to increase with DFNS loading due to modifications in the chain packing. The higher number of free volume holes provide additional pathways for ionic diffusion leading to an enhancement in ionic conductivity. The role of relative free volume in ionic conductivity enhancement is further established through the strong coupling observed between ionic conduction and segmental relaxations of PEO electrolytes investigated using BDS.","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":"119 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143832139","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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