Two-dimensional metal halide perovskites(2D MHPs)have garnered significant attention for their promising optoelectronic properties,driven by strong excitonic effects and structural tunability.Their photoelectric prope...Two-dimensional metal halide perovskites(2D MHPs)have garnered significant attention for their promising optoelectronic properties,driven by strong excitonic effects and structural tunability.Their photoelectric properties are directly determined by their exciton behavior.Here,we investigate the impact of halogen doping on exciton dynamics and emission characteristics in PEA_(2)Pb(Br_(1-x)Cl_(x))_(4).Systematic Cl-doping engineering induces a remarkable spectral evolution,characterized by a transition from blue emission to white-light emission.This transformation correlates with a unique switching behavior between extrinsic and intrinsic self-trapped exciton(STE)states,as revealed through combined analysis of excited-state transitions and carrier dynamics.Temperature-dependent photoluminescence studies coupled with lattice distortion analysis demonstrate that doping induces subtle structural perturbations within the inorganic framework.These minimal lattice modifications fundamentally reconfigure excitonic behavior.The doping-dependent competition between intrinsic polaronic self-trapping and defect-mediated trapping mechanisms accounts for the observed spectral broadening.Specifically,Cl incorporation below 0.2 preferentially enhances intrinsic STE formation through lattice softening,while higher doping levels introduce defect-assisted trapping pathways.This dual-channel trapping model,validated by temperature-activated detrapping kinetics and transient absorption spectroscopy,provides new insights into defect engineering strategies for tailoring emission characteristics in low-dimensional hybrid perovskites.展开更多
Heteroatom doping has emerged as a powerful strategy to optimize the catalytic and adsorption abilities of electrocatalysts by regulating the electronic structure,thereby enabling the development of efficient electroc...Heteroatom doping has emerged as a powerful strategy to optimize the catalytic and adsorption abilities of electrocatalysts by regulating the electronic structure,thereby enabling the development of efficient electrocatalysts for lithium-sulfur(Li-S)batteries.However,the correlation between the properties of doped atoms and adsorptio n-catalytic ability,as well as the interconnection between adsorption strength and catalytic activity,remains underexplored.Herein,we employed halogen atoms(F,Cl,and Br)with different electronegativities to dope nickel phosphide(Ni_(2)P),aiming to modulate the adsorption properties toward lithium polysulfides(LiPSs).We systematically explored the relationship between the electronegativity of the doping atoms and the adsorption strength,followed by exploring the connection between adsorption and catalytic capabilities.Combined experimental and theoretical analyses reveal that doping halogen atoms effectively strengthens d-p orbital hybridization between Ni atoms and S atoms,thereby enhancing LiPSs anchoring and conversion.Specifically,the chemical adsorption capability is enhanced as the electronegativity of the doped atoms increases.Moreover,the catalytic activity presents a volcano-like trend with the enhancement of adsorption performance,wherein the activity initially increases and subsequently diminishes.Therefore,Cl-doped Ni_(2)P with moderate chemisorption ability exhibits optimal redox kinetics in bidirectional sulfur conversion.Consequently,the Li-S batteries with Cl-Ni_(2)P-separators deliver a high-rate capacity of 790 mAh g^(-1)at 5 C and achieve a remarkable areal capacity of 7.36 mAh cm^(-2)under practical conditions(sulfur loading:7.10 mg cm^(-2);electrolyte/sulfur(E/S)ratio:5μL mg^(-1)).This work uncovers the significance of achieving a balance between adsorption and catalytic capabilities,offering insights into designing efficient electrocatalysts for lithium-sulfur batteries.展开更多
Recent theoretical predictions and experimental findings on the transport properties of n-type SnTe have triggered extensive researches on this simple binary compound,despite the realization of n-type SnTe being a gre...Recent theoretical predictions and experimental findings on the transport properties of n-type SnTe have triggered extensive researches on this simple binary compound,despite the realization of n-type SnTe being a great challenge.Herein,Cl as a donor dopant can effectively regulate the position of Fermi level in Sn_(0.6)Pb_(0.4)Te matrix and successfully achieve the n-type transport behavior in SnTe.An outstanding power factor of~14.7μW·cm^(-1)·K^(-2) at 300 K was obtained for Cl-doped Sn_(0.6)Pb_(0.4)Te sample.By combining the experimental analysis with theoretical calculations,the transport properties of n-type SnTe thermoelectrics doped with different halogen dopants(Cl,Br,and I)were then systematically investigated and estimated.The results demonstrated that Br and I had better doping efficiencies compared with Cl,which contributed to the well-optimized carrier concentrations of~1.03×10^(19)and~1.11×10^(19)cm^(-3)at 300 K,respectively.The improved n-type carrier concentrations effectively lead to the significant enhancement on the thermoelectric performance of n-type SnTe.Our study further promoted the experimental progress and deep interpretation of the transport features in n-type SnTe thermoelectrics.The present results could also be crucial for the development of n-type counterparts for SnTe-based thermoelectric devices.展开更多
Despite utilization of state-of-the-art Cu-based catalysts,achieving high selectivity and stability in multicarbon(C^(2+))compounds production through electrocatalytic CO_(2)reduction reaction(CO_(2)RR)remains a criti...Despite utilization of state-of-the-art Cu-based catalysts,achieving high selectivity and stability in multicarbon(C^(2+))compounds production through electrocatalytic CO_(2)reduction reaction(CO_(2)RR)remains a critical and challenging objective.Here we employ lattice chlorine-doped Cu_(2)O nanocubes(Cl_(d)-Cu_(2)O NCs)with well-defined{100}facets as a model catalyst to demonstrate that halogen doping can serve as a versatile and effective strategy for modulating surface charge distribution,thereby enhancing asymmetric C-C coupling toward high-selectivity C^(2+)products in CO_(2)RR.Compared to Cl-free Cu_(2)O NCs,Cl_(d)-Cu_(2)O NCs exhibit a greatly enhanced C^(2+)Faraday efficiency,i.e.,~85%at-1.1 V(versus the reversible hydrogen electrode).Additionally,the Cl_(d)-Cu_(2)O NCs demonstrate significantly enhanced long-term durability,attributed to better preservation of the cubic morphology and more stable Cu^(δ+)states.In-situ electrochemical studies reveal that Cl_(d)-Cu_(2)O NCs facilitate the formation of the key asymmetric*COH and*OCCOH intermediates,ultimately leading to higher C^(2+)products.Density functional theory(DFT)calculations confirm that the introduced Cl-dopants disrupt the charge balance of the Cu_(2)O(100)surface,enriching the Cl-adjacent Cu atoms with more electrons compared to those near O atoms.This unbalanced charge distribution significantly reduces the free energy of the rate-determining step for asymmetric C-C coupling from the*CO to*OCCOH on Cl-doped Cu_(2)O(100)surface,requiring only 1.04 e V,in contrast to 1.50 e V on pristine Cu_(2)O(100)surface.This study provides valuable insights into the surface charge modulation of Cu_(2)O catalysts via halogen doping for enhancing asymmetric C-C coupling and C^(2+)production in CO_(2)RR.展开更多
Three-dimensional hierarchical structure coral-like BaTiO3 nanoparticles have been self-assembled by a facile one step hydrothermal method. Cetyltrimethyl ammonium bromide(CTAB),Ba(OH)2·8H2O and tetrabutyl titana...Three-dimensional hierarchical structure coral-like BaTiO3 nanoparticles have been self-assembled by a facile one step hydrothermal method. Cetyltrimethyl ammonium bromide(CTAB),Ba(OH)2·8H2O and tetrabutyl titanate have been used as precursors. The prepared Ba TiO3 exhibits cubic perovskite phase at room temperature,and the coral-like architecture is a micro-nano hiberarchy consisted of dendrimer-like structure and trunk-like structure. By adjusting the hydrothermal duration and the precursor substances,a surfactant induced mechanism is proposed to understand the self-assembly process. UV-vis measurement demonstrates that the as-prepared Ba TiO3 nanoparticles exhibit dozens of times overwhelming absorptive character compared to the ordinary nanospheres at ultraviolet band,which is benefited from the coral-like porous framework. Moreover,halogen anions( F,Cl,Br,and I) have been chosen to adjust the coral-like Ba TiO3 physical properties. Results show the halogen doping produces distinct modulation effect on the grain size,UV-vis absorbance and photoluminescence properties of the materials. The coral-like BaTiO3 nanoparticle and its halogen modified ramifications offer significant opportunities to develop nano-laser devices,photon detectors,photocatalyst based on BaTiO3 perovskite materials.展开更多
基金supported by the National Key R&D Program of China(2023YFB3507900)National Natural Science Foundation of China(51972006,22471009,and 12174016)+2 种基金Beijing Nova Program(20230484350)Beijing Natural Science Foundation(2222050)Hu Q also thanks the financial support from the Hubei Natural Science Foundation(2023AFB590).
文摘Two-dimensional metal halide perovskites(2D MHPs)have garnered significant attention for their promising optoelectronic properties,driven by strong excitonic effects and structural tunability.Their photoelectric properties are directly determined by their exciton behavior.Here,we investigate the impact of halogen doping on exciton dynamics and emission characteristics in PEA_(2)Pb(Br_(1-x)Cl_(x))_(4).Systematic Cl-doping engineering induces a remarkable spectral evolution,characterized by a transition from blue emission to white-light emission.This transformation correlates with a unique switching behavior between extrinsic and intrinsic self-trapped exciton(STE)states,as revealed through combined analysis of excited-state transitions and carrier dynamics.Temperature-dependent photoluminescence studies coupled with lattice distortion analysis demonstrate that doping induces subtle structural perturbations within the inorganic framework.These minimal lattice modifications fundamentally reconfigure excitonic behavior.The doping-dependent competition between intrinsic polaronic self-trapping and defect-mediated trapping mechanisms accounts for the observed spectral broadening.Specifically,Cl incorporation below 0.2 preferentially enhances intrinsic STE formation through lattice softening,while higher doping levels introduce defect-assisted trapping pathways.This dual-channel trapping model,validated by temperature-activated detrapping kinetics and transient absorption spectroscopy,provides new insights into defect engineering strategies for tailoring emission characteristics in low-dimensional hybrid perovskites.
基金supported by the Beijing Institute of Technology Research Fund Program for Young Scholars and 21C Innovation Laboratory Contemporary Amperex Technology Co.,Limited,Ninde,352100,China(21C-OP-202314)。
文摘Heteroatom doping has emerged as a powerful strategy to optimize the catalytic and adsorption abilities of electrocatalysts by regulating the electronic structure,thereby enabling the development of efficient electrocatalysts for lithium-sulfur(Li-S)batteries.However,the correlation between the properties of doped atoms and adsorptio n-catalytic ability,as well as the interconnection between adsorption strength and catalytic activity,remains underexplored.Herein,we employed halogen atoms(F,Cl,and Br)with different electronegativities to dope nickel phosphide(Ni_(2)P),aiming to modulate the adsorption properties toward lithium polysulfides(LiPSs).We systematically explored the relationship between the electronegativity of the doping atoms and the adsorption strength,followed by exploring the connection between adsorption and catalytic capabilities.Combined experimental and theoretical analyses reveal that doping halogen atoms effectively strengthens d-p orbital hybridization between Ni atoms and S atoms,thereby enhancing LiPSs anchoring and conversion.Specifically,the chemical adsorption capability is enhanced as the electronegativity of the doped atoms increases.Moreover,the catalytic activity presents a volcano-like trend with the enhancement of adsorption performance,wherein the activity initially increases and subsequently diminishes.Therefore,Cl-doped Ni_(2)P with moderate chemisorption ability exhibits optimal redox kinetics in bidirectional sulfur conversion.Consequently,the Li-S batteries with Cl-Ni_(2)P-separators deliver a high-rate capacity of 790 mAh g^(-1)at 5 C and achieve a remarkable areal capacity of 7.36 mAh cm^(-2)under practical conditions(sulfur loading:7.10 mg cm^(-2);electrolyte/sulfur(E/S)ratio:5μL mg^(-1)).This work uncovers the significance of achieving a balance between adsorption and catalytic capabilities,offering insights into designing efficient electrocatalysts for lithium-sulfur batteries.
基金supported by the National Natural Science Foundation of China(No.52002042)the National Postdoctoral Program for Innovative Talents(No.BX20200028)+3 种基金the National Key Research and Development Program of China(No.2018YFA0702100)China Postdoctoral Science Foundation(No.2021M690280)the Natural Science Foundation of Chongqing,China(No.cstc2019jcyj-msxmX0554)the support from the National Science Fund for Distinguished Young Scholars(No.51925101)。
文摘Recent theoretical predictions and experimental findings on the transport properties of n-type SnTe have triggered extensive researches on this simple binary compound,despite the realization of n-type SnTe being a great challenge.Herein,Cl as a donor dopant can effectively regulate the position of Fermi level in Sn_(0.6)Pb_(0.4)Te matrix and successfully achieve the n-type transport behavior in SnTe.An outstanding power factor of~14.7μW·cm^(-1)·K^(-2) at 300 K was obtained for Cl-doped Sn_(0.6)Pb_(0.4)Te sample.By combining the experimental analysis with theoretical calculations,the transport properties of n-type SnTe thermoelectrics doped with different halogen dopants(Cl,Br,and I)were then systematically investigated and estimated.The results demonstrated that Br and I had better doping efficiencies compared with Cl,which contributed to the well-optimized carrier concentrations of~1.03×10^(19)and~1.11×10^(19)cm^(-3)at 300 K,respectively.The improved n-type carrier concentrations effectively lead to the significant enhancement on the thermoelectric performance of n-type SnTe.Our study further promoted the experimental progress and deep interpretation of the transport features in n-type SnTe thermoelectrics.The present results could also be crucial for the development of n-type counterparts for SnTe-based thermoelectric devices.
基金supported by the National Natural Science Foundation of China(U24A20563,22171093)the Natural Science Foundation of Fujian Province(2022J02008)+5 种基金the Fujian Provincial Chemistry Discipline Alliance Foundationthe Scientific Research Funds of Huaqiao Universitythe support from the Early Career Scheme grant(21300323)the General Research Fund(11309025)from the Research Grants Council of the Hong Kong Special Administrative Regionthe Guang Dong Basic and Applied Basic Research Foundation(2025A1515010008)the CityU funds(9610600,9610663,7020103)。
文摘Despite utilization of state-of-the-art Cu-based catalysts,achieving high selectivity and stability in multicarbon(C^(2+))compounds production through electrocatalytic CO_(2)reduction reaction(CO_(2)RR)remains a critical and challenging objective.Here we employ lattice chlorine-doped Cu_(2)O nanocubes(Cl_(d)-Cu_(2)O NCs)with well-defined{100}facets as a model catalyst to demonstrate that halogen doping can serve as a versatile and effective strategy for modulating surface charge distribution,thereby enhancing asymmetric C-C coupling toward high-selectivity C^(2+)products in CO_(2)RR.Compared to Cl-free Cu_(2)O NCs,Cl_(d)-Cu_(2)O NCs exhibit a greatly enhanced C^(2+)Faraday efficiency,i.e.,~85%at-1.1 V(versus the reversible hydrogen electrode).Additionally,the Cl_(d)-Cu_(2)O NCs demonstrate significantly enhanced long-term durability,attributed to better preservation of the cubic morphology and more stable Cu^(δ+)states.In-situ electrochemical studies reveal that Cl_(d)-Cu_(2)O NCs facilitate the formation of the key asymmetric*COH and*OCCOH intermediates,ultimately leading to higher C^(2+)products.Density functional theory(DFT)calculations confirm that the introduced Cl-dopants disrupt the charge balance of the Cu_(2)O(100)surface,enriching the Cl-adjacent Cu atoms with more electrons compared to those near O atoms.This unbalanced charge distribution significantly reduces the free energy of the rate-determining step for asymmetric C-C coupling from the*CO to*OCCOH on Cl-doped Cu_(2)O(100)surface,requiring only 1.04 e V,in contrast to 1.50 e V on pristine Cu_(2)O(100)surface.This study provides valuable insights into the surface charge modulation of Cu_(2)O catalysts via halogen doping for enhancing asymmetric C-C coupling and C^(2+)production in CO_(2)RR.
基金financially supported by the One Hundred Talents Project Foundation Program (1029271301)the Western Light Talent Culture Project (Grant No.RCPY201206) of Chinese Academy of Sciences+1 种基金the National Natural Science Foundation of China (Grant Nos.41302029 and 41130746)the International Technology Cooperation Foundation of Autonomous Region (20136009)
文摘Three-dimensional hierarchical structure coral-like BaTiO3 nanoparticles have been self-assembled by a facile one step hydrothermal method. Cetyltrimethyl ammonium bromide(CTAB),Ba(OH)2·8H2O and tetrabutyl titanate have been used as precursors. The prepared Ba TiO3 exhibits cubic perovskite phase at room temperature,and the coral-like architecture is a micro-nano hiberarchy consisted of dendrimer-like structure and trunk-like structure. By adjusting the hydrothermal duration and the precursor substances,a surfactant induced mechanism is proposed to understand the self-assembly process. UV-vis measurement demonstrates that the as-prepared Ba TiO3 nanoparticles exhibit dozens of times overwhelming absorptive character compared to the ordinary nanospheres at ultraviolet band,which is benefited from the coral-like porous framework. Moreover,halogen anions( F,Cl,Br,and I) have been chosen to adjust the coral-like Ba TiO3 physical properties. Results show the halogen doping produces distinct modulation effect on the grain size,UV-vis absorbance and photoluminescence properties of the materials. The coral-like BaTiO3 nanoparticle and its halogen modified ramifications offer significant opportunities to develop nano-laser devices,photon detectors,photocatalyst based on BaTiO3 perovskite materials.
