The H^++CO2 reaction at high energies is relevant in atmospheric chemistry,astrophysics,and proton cancer therapy research.Therefore,we present herein a complete investigation of H^++CO2 at ELab=30 eV with the simples...The H^++CO2 reaction at high energies is relevant in atmospheric chemistry,astrophysics,and proton cancer therapy research.Therefore,we present herein a complete investigation of H^++CO2 at ELab=30 eV with the simplest-level electron nuclear dynamics(SLEND)method.SLEND describes nuclei via classical mechanics and electrons with a singledeterminantal Thouless wavefunction.The 3402 SLEND conducted simulations from 42 independent CO2 target orientations provide a full description of all the reactive processes and their mechanisms in this system:non-charge-transfer scattering(NCTS),charge-transfer scattering(CTS),and single C=O bond dissociation;all this valuable information about reactivity is not accessible experimentally.Numerous details of the projectile scattering patterns are provided,including the appearance and coalescence of primary and secondary rainbow angles as a function of the target orientation.SLEND NCTS and CTS differential cross sections(DCSs)are evaluated in conjunction with advanced semi-classical techniques.SLEND NCTS DCS agrees well with its experimental counterpart at all the measured scattering angles,whereas SLEND CTS DCS agrees well at high scattering angles but less satisfactorily at lower ones.Remarkably,both NCTS and CTS SLEND DCSs predict the primary rainbow angle signatures in agreement with the experiment.展开更多
Doping of semiconductors,i.e.,accurately modulating the charge carrier type and concentration in a controllable manner,is a key technology foundation for modern electronics and optoelectronics.However,the conventional...Doping of semiconductors,i.e.,accurately modulating the charge carrier type and concentration in a controllable manner,is a key technology foundation for modern electronics and optoelectronics.However,the conventional doping technologies widely utilized in silicon industry,such as ion implantation and thermal diffusion,always fail when applied to two-dimensional(2D)materials with atomically-thin nature.Surface charge transfer doping(SCTD)is emerging as an effective and non-destructive doping technique to provide reliable doping capability for 2D materials,in particular 2D semiconductors.Herein,we summarize the recent advances and developments on the SCTD of 2D semiconductors and its application in electronic and optoelectronic devices.The underlying mechanism of STCD processes on 2D semiconductors is briefly introduced.Its impact on tuning the fundamental properties of various 2D systems is highlighted.We particularly emphasize on the SCTD-enabled high-performance 2D functional devices.Finally,the challenges and opportunities for the future development of SCTD are discussed.展开更多
Photoinduced interfacial charge transfer plays a critical role in energy conversion involving van der Waals(vdW)heterostructures constructed of inorganic nanostructures and organic materials.However,the effect of mole...Photoinduced interfacial charge transfer plays a critical role in energy conversion involving van der Waals(vdW)heterostructures constructed of inorganic nanostructures and organic materials.However,the effect of molecular stacking configurations on charge transfer dynamics is less understood.In this study,we demonstrated the tunability of interfacial charge separation in a type-Ⅱ heterojunction between monolayer(ML)WS_(2) and an organic semiconducting molecule[2-(3″′,4′-dimethyl-[2,2′:5′,2′:5″,2″′-quaterthiophen]-5-yl)ethan-1-ammonium halide(4Tm)]by rational design of relative stacking configurations.The assembly between ML-WS_(2) and the 4Tm molecule forms a face-to-face stacking when 4Tm molecules are in a selfaggregation state.In contrast,a face-to-edge stacking is observed when 4Tm molecule is incorporated into a 2D organic-inorganic hybrid perovskite lattice.The face-to-face stacking was proved to be more favorable for hole transfer from WS_(2) to 4Tm and led to interlayer excitons(IEs)emission.Transient absorption measurements show that the hole transfer occurs on a time scale of 150 fs.On the other hand,the face-to-edge stacking resulted in much slower hole transfer without formation of IEs.This inefficient hole transfer occurs on a similar time scale as A exciton recombination in WS_(2),leading to the formation of negative trions.These investigations offer important fundamental insights into the charge transfer processes at organic−inorganic interfaces.展开更多
Although two-dimensional perovskite devices are highly stable,they also lead to a number of challenges.For instance,the introduction of large organic amines makes crystallization process complicated,causing problems s...Although two-dimensional perovskite devices are highly stable,they also lead to a number of challenges.For instance,the introduction of large organic amines makes crystallization process complicated,causing problems such as generally small grain size and blocked charge transfer.In this work,imprint assisted with methylamine acetate were used to improve the morphology of the film,optimize the internal phase distribution,and enhance the charge transfer of the perovskite film.Specifically,imprint promoted the dispersion of spacer cations in the recrystallization process with the assistance of methylamine acetate,thus inhibited the formation of low-n phase induced by the aggregation of spacer cations and facilitated the formation of 3D-like phase.In this case,the corresponding quasi-2D perovskite solar cells delivered improved efficiency and exhibited superior stability.Our work provides an effective strategy to obtain uniform phase distribution for quasi-2D perovskite.展开更多
Two-dimensional(2D)semiconductor heterojunctions are considered as an effective strategy to achieve fast separation of photoinduced carriers.Herein,a novel CoWO_(4)/g-C_(3)N_(4)(CWO/CN)p–n junction was synthesized us...Two-dimensional(2D)semiconductor heterojunctions are considered as an effective strategy to achieve fast separation of photoinduced carriers.Herein,a novel CoWO_(4)/g-C_(3)N_(4)(CWO/CN)p–n junction was synthesized using an electrostatic selfassembly method.The constructed 2D/2D p–n heterostructure had a rich hetero-interface,increased charge density,and fast separation efficiency of photoinduced carriers.The in-situ Kelvin probe force microscopy confirmed that the separation pathway of photoinduced carriers through the interface obeyed an II-scheme charge transfer mechanism.Experimental results and density functional theory calculations indicated the differences of work function between CWO and CN induced the generation of built-in electric field,ensuring an efficient separation and transfer process of photoinduced carriers.Under the optimized conditions,the CWO/CN heterojunction displayed enhanced photocatalytic H_(2)generation activity under full spectrum and visible lights irradiation,respectively.Our study provides a novel approach to design 2D/2D hetero-structured photocatalysts based on p–n type semiconductor for photocatalytic H_(2)generation.展开更多
基金Present calculations were performed at the Texas Tech University High Performance Computer Center and the Texas Advanced Computing Center at the University of Texas at Austin.Prof.Morales acknowledges financial support from the Cancer Prevention and Research Institute of Texas(CPRIT)grant RP140478.Prof.Yan acknowledges the financial support from the National Natural Science Foundation of China(No.21373064)and the Program for Innovative Research Team of Guizhou Province(No.QKTD[2014]4021).
文摘The H^++CO2 reaction at high energies is relevant in atmospheric chemistry,astrophysics,and proton cancer therapy research.Therefore,we present herein a complete investigation of H^++CO2 at ELab=30 eV with the simplest-level electron nuclear dynamics(SLEND)method.SLEND describes nuclei via classical mechanics and electrons with a singledeterminantal Thouless wavefunction.The 3402 SLEND conducted simulations from 42 independent CO2 target orientations provide a full description of all the reactive processes and their mechanisms in this system:non-charge-transfer scattering(NCTS),charge-transfer scattering(CTS),and single C=O bond dissociation;all this valuable information about reactivity is not accessible experimentally.Numerous details of the projectile scattering patterns are provided,including the appearance and coalescence of primary and secondary rainbow angles as a function of the target orientation.SLEND NCTS and CTS differential cross sections(DCSs)are evaluated in conjunction with advanced semi-classical techniques.SLEND NCTS DCS agrees well with its experimental counterpart at all the measured scattering angles,whereas SLEND CTS DCS agrees well at high scattering angles but less satisfactorily at lower ones.Remarkably,both NCTS and CTS SLEND DCSs predict the primary rainbow angle signatures in agreement with the experiment.
基金the financial support from Natural Science Foundation of Jiangsu Province(No.BK20170005)the National Natural Science Foundation of China(No.21872100)+1 种基金Singapore MOE Grants MOE2019-T2-1-002 and R143-000-A43-114,Fundamental Research Foundation of Shenzhen(Nos.JCYJ20190808152607389 and JCYJ20170817100405375)Shenzhen Peacock Plan(No.KQTD2016053112042971).
文摘Doping of semiconductors,i.e.,accurately modulating the charge carrier type and concentration in a controllable manner,is a key technology foundation for modern electronics and optoelectronics.However,the conventional doping technologies widely utilized in silicon industry,such as ion implantation and thermal diffusion,always fail when applied to two-dimensional(2D)materials with atomically-thin nature.Surface charge transfer doping(SCTD)is emerging as an effective and non-destructive doping technique to provide reliable doping capability for 2D materials,in particular 2D semiconductors.Herein,we summarize the recent advances and developments on the SCTD of 2D semiconductors and its application in electronic and optoelectronic devices.The underlying mechanism of STCD processes on 2D semiconductors is briefly introduced.Its impact on tuning the fundamental properties of various 2D systems is highlighted.We particularly emphasize on the SCTD-enabled high-performance 2D functional devices.Finally,the challenges and opportunities for the future development of SCTD are discussed.
基金primarily supported by the US Department of Energy,Office of Basic Energy Sciences under award number DE-SC0022082support from National Science Foundation under award number 2143568-DMR.
文摘Photoinduced interfacial charge transfer plays a critical role in energy conversion involving van der Waals(vdW)heterostructures constructed of inorganic nanostructures and organic materials.However,the effect of molecular stacking configurations on charge transfer dynamics is less understood.In this study,we demonstrated the tunability of interfacial charge separation in a type-Ⅱ heterojunction between monolayer(ML)WS_(2) and an organic semiconducting molecule[2-(3″′,4′-dimethyl-[2,2′:5′,2′:5″,2″′-quaterthiophen]-5-yl)ethan-1-ammonium halide(4Tm)]by rational design of relative stacking configurations.The assembly between ML-WS_(2) and the 4Tm molecule forms a face-to-face stacking when 4Tm molecules are in a selfaggregation state.In contrast,a face-to-edge stacking is observed when 4Tm molecule is incorporated into a 2D organic-inorganic hybrid perovskite lattice.The face-to-face stacking was proved to be more favorable for hole transfer from WS_(2) to 4Tm and led to interlayer excitons(IEs)emission.Transient absorption measurements show that the hole transfer occurs on a time scale of 150 fs.On the other hand,the face-to-edge stacking resulted in much slower hole transfer without formation of IEs.This inefficient hole transfer occurs on a similar time scale as A exciton recombination in WS_(2),leading to the formation of negative trions.These investigations offer important fundamental insights into the charge transfer processes at organic−inorganic interfaces.
基金support from the National Natural Science Foundation of China(NSFC)(52163019,22005131,52173169 and U20A20128)support from the Natural Science Foundation of Jiangxi Province(20224ACB214006)。
文摘Although two-dimensional perovskite devices are highly stable,they also lead to a number of challenges.For instance,the introduction of large organic amines makes crystallization process complicated,causing problems such as generally small grain size and blocked charge transfer.In this work,imprint assisted with methylamine acetate were used to improve the morphology of the film,optimize the internal phase distribution,and enhance the charge transfer of the perovskite film.Specifically,imprint promoted the dispersion of spacer cations in the recrystallization process with the assistance of methylamine acetate,thus inhibited the formation of low-n phase induced by the aggregation of spacer cations and facilitated the formation of 3D-like phase.In this case,the corresponding quasi-2D perovskite solar cells delivered improved efficiency and exhibited superior stability.Our work provides an effective strategy to obtain uniform phase distribution for quasi-2D perovskite.
基金Outstanding Talent Research Fund of Zhengzhou University,China Postdoctoral Science Foundation(Nos.2020TQ0277 and 2020M682328)Central Plains Science and Technology Innovation Leader Project(No.214200510006)Postdoctoral Science Foundation of Henan province(No.202002010).
文摘Two-dimensional(2D)semiconductor heterojunctions are considered as an effective strategy to achieve fast separation of photoinduced carriers.Herein,a novel CoWO_(4)/g-C_(3)N_(4)(CWO/CN)p–n junction was synthesized using an electrostatic selfassembly method.The constructed 2D/2D p–n heterostructure had a rich hetero-interface,increased charge density,and fast separation efficiency of photoinduced carriers.The in-situ Kelvin probe force microscopy confirmed that the separation pathway of photoinduced carriers through the interface obeyed an II-scheme charge transfer mechanism.Experimental results and density functional theory calculations indicated the differences of work function between CWO and CN induced the generation of built-in electric field,ensuring an efficient separation and transfer process of photoinduced carriers.Under the optimized conditions,the CWO/CN heterojunction displayed enhanced photocatalytic H_(2)generation activity under full spectrum and visible lights irradiation,respectively.Our study provides a novel approach to design 2D/2D hetero-structured photocatalysts based on p–n type semiconductor for photocatalytic H_(2)generation.
基金We sincerely thank Prof. Yong-fang Li for providing the samples. S. Vdovi5 thanks CAS for support through a CAS Research Fellowship for International Young Researchers. This work was supported by National Natural Science Foundation of China, the Chinese Academy of Sciences, and the State Key Project for Fundamental Research.
基金This work was supported by the National Natural Science Foundation of China （No.10604012, No.10974023, No.10874234, No.20703064, No.90923003）, the National Basic Research Project of China （No.2009CB930Y01）, and the Fundamental Research Funds for the Central Universities （No.DUT10LK03）.
