Upconversion luminescent(UCL)materials have broad application prospects in the field of temperature sensing;thus,improving the luminescence performance and temperature measurement sensitivity of upconversion phosphors...Upconversion luminescent(UCL)materials have broad application prospects in the field of temperature sensing;thus,improving the luminescence performance and temperature measurement sensitivity of upconversion phosphors is highly important.In this study,SrAl_(2)Si_(2)O_(8)with good thermal stability was doped with Ho^(3+)and Yb^(3+),and the optimal concentration was determined to be S rAl_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)(in mole fraction).A series of(Sr_(0.87-x)Ba_(x))Al_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)phosphor samples was prepared by using a cationic substitution strategy and further doping Ba^(2+)to replace the Sr^(2+)lattice in the matrix.The re sults show that the introduction of Ba^(2+)effectively replaces Sr^(2+)and significantly increases the upconversion fluorescence emission intensity of SrAl_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)by approximately 2.9times.The temperature sensing properties of SrAl_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)and Sr_(0.3)7Ba_(0.5)0Al_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)were investigated.The Ho^(3+)-based5F5and5S2/5F4nonthermal coupled energy level fluorescence intensity ratio(FIR)techniques in the Ba_(0.3)7S r_(0.50)Al_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)phosphors show a maximum temperature measurement absolute sensitivity of 4.32%/K at 573 K and a maximum relative sensitivity of 1.08%/K at 373 K;these values are 5.8 and 3.2 times greater,respectively,than that of the non-Ba^(2+)-doped SrAl_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)phosphor.These results not only confirm the effectiveness of the cation substitution strategy in enhancing the upconversion luminescence performance and temperature sensing characteristics but also provide a scientific basis for the design of high-performance optical temperature sensors.展开更多
Given their unique structure-dependent properties,strategically designing semiconductor-based photocatalysts,which expose highly reactive crystalline facets,is widely used to tune their performance.Herein,AgBr/Ag/TiO_...Given their unique structure-dependent properties,strategically designing semiconductor-based photocatalysts,which expose highly reactive crystalline facets,is widely used to tune their performance.Herein,AgBr/Ag/TiO_(2){100}nanorods Z-scheme heterojunction composites were prepared via hydrothermal and in situ facet-induced reduction.Transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,electron paramagnetic resonance spectroscopy,and density functional theory calculations reveal that the selective exposure of TiO_(2){100}facets with abundant oxygen vacancies(OV)promotes the formation of metallic silver on the interfaces between AgBr and TiO_(2){100}.Metallic silver can mediate interfacial charge transfer by facilitating the photogenerated carrier recombination of the conduction band of TiO_(2){100}and the valence band of AgBr.As a result,a Z-scheme heterojunction is formed in AgBr/Ag/TiO_(2){100}.The AgBr/Ag/TiO_(2){100}exhibits faster degradation of tetracycline in aqueous solution compared to pristine AgBr,TiO_(2){101},TiO_(2){100}and AgBr/TiO_(2){101}p-n heterojunctions.This is attributed to the effect of the Z-scheme heterojunction on prolonging the lifetime of photogenerated carriers,which is confirmed by femtosecond transient absorption spectroscopy.The photocatalytic mechanism and degradation pathways are discussed along with a toxicity assessment of the intermediates.Overall,this work develops a new approach for designing Z-scheme heterojunction photocatalysts via selective facet control of anatase TiO_(2).展开更多
Web 2.0的出现使信息构建(IA)的内容发生了深刻变化,IA已进入"信息构建2.0"(IA2.0)阶段。在IA2.0阶段,IA作为一门学科、一种角色和一类社团的协调统一体而存在,它强调真正"以用户为中心"和"丰富的用户体验&qu...Web 2.0的出现使信息构建(IA)的内容发生了深刻变化,IA已进入"信息构建2.0"(IA2.0)阶段。在IA2.0阶段,IA作为一门学科、一种角色和一类社团的协调统一体而存在,它强调真正"以用户为中心"和"丰富的用户体验"的核心理念,以满足新环境下的用户需求。Web2.0网站的IA,是IA2.0的典型应用,也是IA2.0阶段研究的主要内容,本文将其称为网站IA2.0。文中设计了一个网站IA2.0模型,并进行了简单的实例分析。展开更多
基金Project supported by the National Natural Science Foundation of China(12264050)Natural Science Foundation of Xinjiang Uygur Autonomous Region(2022D01C727)Talent Project of Tianchi Doctoral Program in Xinjiang Uygur Autonomous Region(0301050903)。
文摘Upconversion luminescent(UCL)materials have broad application prospects in the field of temperature sensing;thus,improving the luminescence performance and temperature measurement sensitivity of upconversion phosphors is highly important.In this study,SrAl_(2)Si_(2)O_(8)with good thermal stability was doped with Ho^(3+)and Yb^(3+),and the optimal concentration was determined to be S rAl_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)(in mole fraction).A series of(Sr_(0.87-x)Ba_(x))Al_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)phosphor samples was prepared by using a cationic substitution strategy and further doping Ba^(2+)to replace the Sr^(2+)lattice in the matrix.The re sults show that the introduction of Ba^(2+)effectively replaces Sr^(2+)and significantly increases the upconversion fluorescence emission intensity of SrAl_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)by approximately 2.9times.The temperature sensing properties of SrAl_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)and Sr_(0.3)7Ba_(0.5)0Al_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)were investigated.The Ho^(3+)-based5F5and5S2/5F4nonthermal coupled energy level fluorescence intensity ratio(FIR)techniques in the Ba_(0.3)7S r_(0.50)Al_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)phosphors show a maximum temperature measurement absolute sensitivity of 4.32%/K at 573 K and a maximum relative sensitivity of 1.08%/K at 373 K;these values are 5.8 and 3.2 times greater,respectively,than that of the non-Ba^(2+)-doped SrAl_(2)Si_(2)O_(8):1%Ho^(3+),12%Yb^(3+)phosphor.These results not only confirm the effectiveness of the cation substitution strategy in enhancing the upconversion luminescence performance and temperature sensing characteristics but also provide a scientific basis for the design of high-performance optical temperature sensors.
文摘Given their unique structure-dependent properties,strategically designing semiconductor-based photocatalysts,which expose highly reactive crystalline facets,is widely used to tune their performance.Herein,AgBr/Ag/TiO_(2){100}nanorods Z-scheme heterojunction composites were prepared via hydrothermal and in situ facet-induced reduction.Transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,electron paramagnetic resonance spectroscopy,and density functional theory calculations reveal that the selective exposure of TiO_(2){100}facets with abundant oxygen vacancies(OV)promotes the formation of metallic silver on the interfaces between AgBr and TiO_(2){100}.Metallic silver can mediate interfacial charge transfer by facilitating the photogenerated carrier recombination of the conduction band of TiO_(2){100}and the valence band of AgBr.As a result,a Z-scheme heterojunction is formed in AgBr/Ag/TiO_(2){100}.The AgBr/Ag/TiO_(2){100}exhibits faster degradation of tetracycline in aqueous solution compared to pristine AgBr,TiO_(2){101},TiO_(2){100}and AgBr/TiO_(2){101}p-n heterojunctions.This is attributed to the effect of the Z-scheme heterojunction on prolonging the lifetime of photogenerated carriers,which is confirmed by femtosecond transient absorption spectroscopy.The photocatalytic mechanism and degradation pathways are discussed along with a toxicity assessment of the intermediates.Overall,this work develops a new approach for designing Z-scheme heterojunction photocatalysts via selective facet control of anatase TiO_(2).
