Lanthanide ions(Ln^(3+))doping provides a potential strategy to control over the luminescent properties of lead-free halide double perovskite nanocrystals(DP NCs).However,due to the low energy transfer efficiency betw...Lanthanide ions(Ln^(3+))doping provides a potential strategy to control over the luminescent properties of lead-free halide double perovskite nanocrystals(DP NCs).However,due to the low energy transfer efficiency between self-trapped exciton(STE)and Ln^(3+)ions,the characteristic emissions of Ln^(3+)ions are not prominent.Furthermore,the energy transfer mechanism between STE and Ln^(3+)ions is also elusive and requires in-depth study.We chose trace Bi^(3+)-doped Cs_(2)Ag_(0.6)Na_(0.4)InCl_(6-x)Br_(x) as a representative DP matrix to demonstrate that by tuning the bromide concentration,the Ln^(3+)emission can be greatly enhanced.Such enhanced STE and Ln^(3+)ions energy transfer originates from the high covalency of Ln-Br bond,which contributes to improve ment of the characteristic emission of Ln^(3+)ions.Furthermo re,optical spectroscopy reveals that the energy transfer mechanism from DP to Eu^(3+)ions is different from all the other doped Ln^(3+)ions.The energy transfer from DP to Eu^(3+)ions is mostly through Eu-Br charge transfer while the other Ln^(3+)ions are excited by energy transfer from STE.The distinct energy transfer mechanism has resulted from the energy separation between the excited energy level of Ln^(3+)ions and the bottom of conduction band of DP.With increasing the energy separation,the energy transfer from STE to Ln^(3+)ions is less efficient because of the generation of a larger number of phonons and finally becomes impossible for Eu^(3+)ions.Our results provide new insight into tuning the energy transfer of Ln^(3+)-doped DP NCs.展开更多
Recent interest in photocatalytic water splitting has intensified the demand in the development of photocatalysts capable of harnessing the full solar-spectrum.This study introduces a novel WO_(x)/ZnIn_(2)S_(4)Zscheme...Recent interest in photocatalytic water splitting has intensified the demand in the development of photocatalysts capable of harnessing the full solar-spectrum.This study introduces a novel WO_(x)/ZnIn_(2)S_(4)Zscheme heterojunction,prepared by depositing ZnIn_(2)S_(4)(ZIS)nanosheets onto WO_(x)nanorods,enabling efficient photothermal-coupled photocatalytic H_(2)evolution.The success relies on the engineered oxygen vacancies within WO_(x)nanorods,which not only confer excellent photothermal properties lowering the reaction barrier but also create defect levels in WO_(x)facilitating Z-scheme electron transfer from these levels to the valence band of ZIS.Consequently,the optimized WO_(x)/ZIS heterojunction exhibits a remarkable H_(2)evolution rate of 33.91 mmol h^(-1)g^(-1)with an apparent quantum efficiency of 23.6%at 400 nm.This study provides a new strategy for developing efficient Z-scheme heterojunctions with broadspectrum solar hydrogen production capabilities.展开更多
Due to great business potential in E-commerce,the traditional method is not an appropriate technique to make investment decision.Consequently,a new approach--Real Option should be applied.Based on the characteristics ...Due to great business potential in E-commerce,the traditional method is not an appropriate technique to make investment decision.Consequently,a new approach--Real Option should be applied.Based on the characteristics of investment in E-commerce,this paper analyzes the function and advantages of the Real Option and the differences between the NPV and Real Option.展开更多
With reform, Chinese urbanization makes an obvious progress. The urban quantity, urban scale, and urban population become more and more. Urban economy has ：become a more important component of the national economy. H...With reform, Chinese urbanization makes an obvious progress. The urban quantity, urban scale, and urban population become more and more. Urban economy has ：become a more important component of the national economy. However, the process of urbanization is either in theory or in practice continually faced with serious new challenge. It is a focus on urban development in China.展开更多
We report a photothermally-induced liquid-solid/gas-solid-decoupling photocatalytic water-splitting system,where a carbonized melamine foam(CMF)and a porous g-C_(3)N_(4)(PCN)serve as the photothermal substrate and mod...We report a photothermally-induced liquid-solid/gas-solid-decoupling photocatalytic water-splitting system,where a carbonized melamine foam(CMF)and a porous g-C_(3)N_(4)(PCN)serve as the photothermal substrate and model photocatalyst,respectively.Specifically,liquid water is transformed into the gaseous phase over the CMF due to the photothermal effect,and the generated vapor can be split into hydrogen by PCN via the photocatalysis.This unique biphasic photocatalytic system exhibits a high hydrogen production rate of 368.1µmol h^(-1),which is 2.4 and 25.6 times larger than those of the traditional triphasic PCN system(151.7µmol h^(-1))and g-C_(3)N_(4)(CN)system(14.4µmol h^(-1)),respectively.The improved photocatalytic performance is mainly attributed to the optimized energy and mass transfer at the gas-liquid-solid reaction interface,where gas products are rapidly desorbed in the photocatalytic process.This work provides a novel strategy to enhance the photocatalytic performance from the perspectives of energy and mass flow.展开更多
The practical application of all-inorganic semiconductor lead halide perovskite nanocrystals(LHP NCs)has been limited by their poor stability.Recently,a lot of research on core-shell structure has been done to improve...The practical application of all-inorganic semiconductor lead halide perovskite nanocrystals(LHP NCs)has been limited by their poor stability.Recently,a lot of research on core-shell structure has been done to improve the stability of perovskite NCs,but the effect was far from the application requirements.Herein,we,for the first time,report a convenient approach to synthesize organic-inorganic double shell CsPbBr_(3)@SiO_(2)@polystyrene(PS)NCs with an inter-core of CsPbBr_(3),the intermediate layer of SiO_(2)shell,and outmost PS shell.Particularly,the CsPbBr_(3)@SiO_(2)@PS NCs maintained more than 90%of their initial photoluminescence(PL)intensity under one month's ultraviolet lamp irradiation or in 85℃ and 85%relative humidity(RH)condition.The white-light-emitting-diodes(WLEDs)were fabricated by encapsulating commercial InGaN chip with CsPbBr_(3)@SiO_(2)@PS NCs and K2SiF6:Mn^(4+)(KSF:Mn^(4+))phosphor with a luminous efficacy of~100 lm/W at 20 mA current and a color gamut of 128%of the National Television Standards Committee(NTSC)standard.In addition,these WLEDs still maintain 91%of the initial luminous efficacy after 1200 h of continuous lighting.These results demonstrated that double shell-protected CsPbBr_(3)perovskite NCs have great potential in the field of WLEDs.展开更多
基金Project supported by the Research Project of Mindu Innovation Laboratory(2021ZZ114)Natural Science Foundation of Xiamen(3502Z20227255)+1 种基金Major Research Project of Xiamen(3502Z20191015)the Science and Technology Major Project of Fujian Province(2021HZ021013)。
文摘Lanthanide ions(Ln^(3+))doping provides a potential strategy to control over the luminescent properties of lead-free halide double perovskite nanocrystals(DP NCs).However,due to the low energy transfer efficiency between self-trapped exciton(STE)and Ln^(3+)ions,the characteristic emissions of Ln^(3+)ions are not prominent.Furthermore,the energy transfer mechanism between STE and Ln^(3+)ions is also elusive and requires in-depth study.We chose trace Bi^(3+)-doped Cs_(2)Ag_(0.6)Na_(0.4)InCl_(6-x)Br_(x) as a representative DP matrix to demonstrate that by tuning the bromide concentration,the Ln^(3+)emission can be greatly enhanced.Such enhanced STE and Ln^(3+)ions energy transfer originates from the high covalency of Ln-Br bond,which contributes to improve ment of the characteristic emission of Ln^(3+)ions.Furthermo re,optical spectroscopy reveals that the energy transfer mechanism from DP to Eu^(3+)ions is different from all the other doped Ln^(3+)ions.The energy transfer from DP to Eu^(3+)ions is mostly through Eu-Br charge transfer while the other Ln^(3+)ions are excited by energy transfer from STE.The distinct energy transfer mechanism has resulted from the energy separation between the excited energy level of Ln^(3+)ions and the bottom of conduction band of DP.With increasing the energy separation,the energy transfer from STE to Ln^(3+)ions is less efficient because of the generation of a larger number of phonons and finally becomes impossible for Eu^(3+)ions.Our results provide new insight into tuning the energy transfer of Ln^(3+)-doped DP NCs.
基金supported by the National Key Research and Development Program of China(2022YFB3803600)the National Natural Science Foundation of China(52276212)+4 种基金the Natural Science Foundation of Jiangsu Province(BK20231211)the Suzhou Science and Technology Program(SYG202101)the Key Research and Development Program in Shaanxi Province of China(2023-YBGY-300)the Zhuhai Innovation and Entrepreneurship Team Project(2120004000225)the China Fundamental Research Funds for the Central Universities。
文摘Recent interest in photocatalytic water splitting has intensified the demand in the development of photocatalysts capable of harnessing the full solar-spectrum.This study introduces a novel WO_(x)/ZnIn_(2)S_(4)Zscheme heterojunction,prepared by depositing ZnIn_(2)S_(4)(ZIS)nanosheets onto WO_(x)nanorods,enabling efficient photothermal-coupled photocatalytic H_(2)evolution.The success relies on the engineered oxygen vacancies within WO_(x)nanorods,which not only confer excellent photothermal properties lowering the reaction barrier but also create defect levels in WO_(x)facilitating Z-scheme electron transfer from these levels to the valence band of ZIS.Consequently,the optimized WO_(x)/ZIS heterojunction exhibits a remarkable H_(2)evolution rate of 33.91 mmol h^(-1)g^(-1)with an apparent quantum efficiency of 23.6%at 400 nm.This study provides a new strategy for developing efficient Z-scheme heterojunctions with broadspectrum solar hydrogen production capabilities.
文摘Due to great business potential in E-commerce,the traditional method is not an appropriate technique to make investment decision.Consequently,a new approach--Real Option should be applied.Based on the characteristics of investment in E-commerce,this paper analyzes the function and advantages of the Real Option and the differences between the NPV and Real Option.
文摘With reform, Chinese urbanization makes an obvious progress. The urban quantity, urban scale, and urban population become more and more. Urban economy has ：become a more important component of the national economy. However, the process of urbanization is either in theory or in practice continually faced with serious new challenge. It is a focus on urban development in China.
基金supported by the National Key Research and Development Program of China(2022YFB3803600)the National Natural Science Foundation of China(52276212)+4 种基金the Key Research and Development Program in Shaanxi Province of China(2023-YBGY-300)the Natural Science Foundation of Jiangsu Province(BK20231211)the Suzhou Science and Technology Program(SYG202101)Zhuhai Innovation and Entrepreneurship Team Project(2120004000225)the China Fundamental Research Funds for the Central Universities。
文摘We report a photothermally-induced liquid-solid/gas-solid-decoupling photocatalytic water-splitting system,where a carbonized melamine foam(CMF)and a porous g-C_(3)N_(4)(PCN)serve as the photothermal substrate and model photocatalyst,respectively.Specifically,liquid water is transformed into the gaseous phase over the CMF due to the photothermal effect,and the generated vapor can be split into hydrogen by PCN via the photocatalysis.This unique biphasic photocatalytic system exhibits a high hydrogen production rate of 368.1µmol h^(-1),which is 2.4 and 25.6 times larger than those of the traditional triphasic PCN system(151.7µmol h^(-1))and g-C_(3)N_(4)(CN)system(14.4µmol h^(-1)),respectively.The improved photocatalytic performance is mainly attributed to the optimized energy and mass transfer at the gas-liquid-solid reaction interface,where gas products are rapidly desorbed in the photocatalytic process.This work provides a novel strategy to enhance the photocatalytic performance from the perspectives of energy and mass flow.
基金This work was supported by the Priority Research Project of Xiamen(No.3502Z20191015)the Science and Technology Major Project of Fujian Province(No.2021HZ021013)the Major Research Project of Mindu Innovation Laboratory(No.2021ZZ114).
文摘The practical application of all-inorganic semiconductor lead halide perovskite nanocrystals(LHP NCs)has been limited by their poor stability.Recently,a lot of research on core-shell structure has been done to improve the stability of perovskite NCs,but the effect was far from the application requirements.Herein,we,for the first time,report a convenient approach to synthesize organic-inorganic double shell CsPbBr_(3)@SiO_(2)@polystyrene(PS)NCs with an inter-core of CsPbBr_(3),the intermediate layer of SiO_(2)shell,and outmost PS shell.Particularly,the CsPbBr_(3)@SiO_(2)@PS NCs maintained more than 90%of their initial photoluminescence(PL)intensity under one month's ultraviolet lamp irradiation or in 85℃ and 85%relative humidity(RH)condition.The white-light-emitting-diodes(WLEDs)were fabricated by encapsulating commercial InGaN chip with CsPbBr_(3)@SiO_(2)@PS NCs and K2SiF6:Mn^(4+)(KSF:Mn^(4+))phosphor with a luminous efficacy of~100 lm/W at 20 mA current and a color gamut of 128%of the National Television Standards Committee(NTSC)standard.In addition,these WLEDs still maintain 91%of the initial luminous efficacy after 1200 h of continuous lighting.These results demonstrated that double shell-protected CsPbBr_(3)perovskite NCs have great potential in the field of WLEDs.
