Construction of lead halide perovskite nanocrystals(LHP NCs)heterostructures is essential to obtain highly stable photoluminescence and expand their applications.Herein,a novel self-assembly strategy combining with a ...Construction of lead halide perovskite nanocrystals(LHP NCs)heterostructures is essential to obtain highly stable photoluminescence and expand their applications.Herein,a novel self-assembly strategy combining with a solvent-free thermal-assisted synthesis and a water-triggered reaction is developed to subsequently grow BaWO_(4)/CsPbX_(3)/CsPb_(2)X_(5)(X=Cl,Br,I)heterostructures at low nucleation temperature with high crystallinity.The as-obtained ternary BaWO_(4)/CsPbX_(3)/CsPb_(2)X_(5)(X=Cl,Br,I)heterostructures exhibit remarkably enhanced panchromatic emission and ultrastable luminescence ascribing to the low-defect growth based on lattice matching.Stable white light-emitting diodes(WLEDs)have been constructed with a high correlated color temperature(CCT)of 7225 K and luminous efficiency of 74.4 lm·W-1.Ln^(3+)-doped BaWO_(4)/CsPbX_(3)/CsPb_(2)X_(5)(Ln^(3+)=Eu^(3+),Tb^(3+),Dy^(3+),Sm^(3+),Yb^(3+)/Er^(3+))nanocomposites are further designed with excitation-dependent photoluminescence and thermochromic properties,making them excellent candidates for high-level anti-counterfeiting and encryption.This work offers a green and universal approach in assembling CsPbX_(3)(X=Cl,Br,I)on lattice-matched tungstate with adjustable panchromatic emission for versatile optical applications.展开更多
Achievement of high photoluminescence quantum efficiency and thermal stability is challenging for near-infrared(NIR)-emitting phosphors.Here,we designed a“kill two birds with one stone”strategy to simultaneously imp...Achievement of high photoluminescence quantum efficiency and thermal stability is challenging for near-infrared(NIR)-emitting phosphors.Here,we designed a“kill two birds with one stone”strategy to simultaneously improve quantum efficiency and thermal stability of the NIR-emitting Ca_(3)Y_(2-2x)(ZnZr)_(x)Ge_(3)O_(12):Cr garnet system by chemical unit cosubstitution,and revealed universal structure-property relationship and the luminescence optimization mechanism.The cosubstitution of[Zn^(2+)-Zr^(4+)]for[Y^(3+)-Y^(3+)]played a critical role as reductant to promote the valence transformation from Cr^(4+)to Cr^(3+),resulting from the reconstruction of octahedral sites for Cr^(3+).The introduction of[Zn^(2+)-Zr^(4+)]unit also contributed to a rigid crystal structure.These two aspects together realized the high internal quantum efficiency of 96%and excellent thermal stability of 89%@423 K.Moreover,information encryption with“burning after reading”was achieved based on different chemical resistance of the phosphors to acid.The developed NIR-emitting phosphor-converted light-emitting diode demonstrated promising applications in bio-tissue imaging and night vision.This work provides a new perspective for developing high-performance NIR-emitting phosphor materials.展开更多
Red phosphor materials play a key role in improving the lighting and backlit display quality of phosphor-converted white light-emitting diodes(pc-WLEDs).However,the development of a red phosphor with simultaneous high...Red phosphor materials play a key role in improving the lighting and backlit display quality of phosphor-converted white light-emitting diodes(pc-WLEDs).However,the development of a red phosphor with simultaneous high efficiency,excellent thermal stability and high colour purity is still a challenge.In this work,unique non-concentration quenching in solid-solution Cs_(3)Gd_(1-x)Ge_(3)O_(9):xEu^(3+)(CGGO:xEu^(3+))(x=0.1-1.0)phosphors is successfully developed to achieve a highly efficient red-emitting Cs_(3)EuGe_(3)0_(9)(CEGO)phosphor.Under the optimal 464 nm blue light excitation,CEGO shows a strong red emission at 611 nm with a high colour purity of 95.07%and a high internal quantum efficiency of 94%.Impressively,this red-emitting CEGO phosphor exhibits a better thermal stability at higher temperatures(175-250℃,>90%)than typical red K2SiF6:Mn^(4+)and Y203:Eu^(3+)phosphors,and has a remarkable volumetric negative thermal expansion(coefficient of thermal expansion,a=—5.06×10^(-5)/℃,25-250℃).By employing this red CEGO phosphor,a fabricated pc-WLED emits warm white light with colour coordinates(0.364,0.383),a high colour rendering index(CRI=89.7),and a low colour coordinate temperature(CCT=4508 K).These results indicate that this highly efficient red-emitting phosphor has great potential as a red component for pc-WLEDs,opening a new perspective for developing new phosphor materials.展开更多
Near-infrared(NIR)-emitting phosphor-converted light-emitting diodes have attracted widespread attention in various applications based on NIR spectroscopy.Except for typical Cr^(3+)-activated NIR-emitting phosphors,ne...Near-infrared(NIR)-emitting phosphor-converted light-emitting diodes have attracted widespread attention in various applications based on NIR spectroscopy.Except for typical Cr^(3+)-activated NIR-emitting phosphors,next-generation Cr^(3+)-free NIR-emitting phosphors with high efficiency and tunable optical properties are highly desired to enrich the types of NIR luminescent materials for different application fields.Here,we report the Fe^(3+)-activated Sr2−yCay(InSb)1−zSn_(2)zO_(6)phosphors that exhibit unprecedented long-wavelength NIR emission.The overall emission tuning from 885 to 1005 nm with broadened full-width at half maximum from 108 to 146 nm was realized through a crystallographic site engineering strategy.The NIR emission was significantly enhanced after complete Ca^(2+)incorporation owing to the substitution-induced lower symmetry of the Fe^(3+)sites.The Ca_(2)InSbO_(6):Fe^(3+)phosphor peaking at 935 nm showed an ultra-high internal quantum efficiency of 87%.The as-synthesized emission-tunable phosphors demonstrated great potential for NIR spectroscopy detection.This work initiates the development of efficient Fe^(3+)-activated broadband NIR-emitting phosphors and opens up a new avenue for designing NIR-emitting phosphor materials.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22171040,51932009 and 52172166)the Fundamental Research Funds for the Central Universities,China(No.N2105006).
文摘Construction of lead halide perovskite nanocrystals(LHP NCs)heterostructures is essential to obtain highly stable photoluminescence and expand their applications.Herein,a novel self-assembly strategy combining with a solvent-free thermal-assisted synthesis and a water-triggered reaction is developed to subsequently grow BaWO_(4)/CsPbX_(3)/CsPb_(2)X_(5)(X=Cl,Br,I)heterostructures at low nucleation temperature with high crystallinity.The as-obtained ternary BaWO_(4)/CsPbX_(3)/CsPb_(2)X_(5)(X=Cl,Br,I)heterostructures exhibit remarkably enhanced panchromatic emission and ultrastable luminescence ascribing to the low-defect growth based on lattice matching.Stable white light-emitting diodes(WLEDs)have been constructed with a high correlated color temperature(CCT)of 7225 K and luminous efficiency of 74.4 lm·W-1.Ln^(3+)-doped BaWO_(4)/CsPbX_(3)/CsPb_(2)X_(5)(Ln^(3+)=Eu^(3+),Tb^(3+),Dy^(3+),Sm^(3+),Yb^(3+)/Er^(3+))nanocomposites are further designed with excitation-dependent photoluminescence and thermochromic properties,making them excellent candidates for high-level anti-counterfeiting and encryption.This work offers a green and universal approach in assembling CsPbX_(3)(X=Cl,Br,I)on lattice-matched tungstate with adjustable panchromatic emission for versatile optical applications.
基金This work was financially supported by the National Science and Technology Major Project(2022YFB3503800)the National Natural Science Foundation of China(NSFC Nos.51932009,51929201,52072349,52172166,12374386,12374388,12304461,U2005212)+1 种基金the Natural Science Foundation of Zhejiang Province(LR22E020004)the Project funded by China Postdoctoral Science Foundation(2022TQ0365,2023M733436).
文摘Achievement of high photoluminescence quantum efficiency and thermal stability is challenging for near-infrared(NIR)-emitting phosphors.Here,we designed a“kill two birds with one stone”strategy to simultaneously improve quantum efficiency and thermal stability of the NIR-emitting Ca_(3)Y_(2-2x)(ZnZr)_(x)Ge_(3)O_(12):Cr garnet system by chemical unit cosubstitution,and revealed universal structure-property relationship and the luminescence optimization mechanism.The cosubstitution of[Zn^(2+)-Zr^(4+)]for[Y^(3+)-Y^(3+)]played a critical role as reductant to promote the valence transformation from Cr^(4+)to Cr^(3+),resulting from the reconstruction of octahedral sites for Cr^(3+).The introduction of[Zn^(2+)-Zr^(4+)]unit also contributed to a rigid crystal structure.These two aspects together realized the high internal quantum efficiency of 96%and excellent thermal stability of 89%@423 K.Moreover,information encryption with“burning after reading”was achieved based on different chemical resistance of the phosphors to acid.The developed NIR-emitting phosphor-converted light-emitting diode demonstrated promising applications in bio-tissue imaging and night vision.This work provides a new perspective for developing high-performance NIR-emitting phosphor materials.
基金supported by the National Natural Science Foundation of China(NSFC Nos.51932009,51929201,51672265,51672266,51750110511,51672257,52072349 and 51672259)Science and Technology Cooperation Project between Chinese and Australian Governments(2017YFE0132300)+1 种基金the Key Research Programme of Frontier Sciences,CAS(Grant No.YZDY-SSW-JSC018)Jiangmen Innovative Research Team Programme(2017)and Major Programme of Basic Research and Applied Research of Guangdong Province(2017KZDXM083).
文摘Red phosphor materials play a key role in improving the lighting and backlit display quality of phosphor-converted white light-emitting diodes(pc-WLEDs).However,the development of a red phosphor with simultaneous high efficiency,excellent thermal stability and high colour purity is still a challenge.In this work,unique non-concentration quenching in solid-solution Cs_(3)Gd_(1-x)Ge_(3)O_(9):xEu^(3+)(CGGO:xEu^(3+))(x=0.1-1.0)phosphors is successfully developed to achieve a highly efficient red-emitting Cs_(3)EuGe_(3)0_(9)(CEGO)phosphor.Under the optimal 464 nm blue light excitation,CEGO shows a strong red emission at 611 nm with a high colour purity of 95.07%and a high internal quantum efficiency of 94%.Impressively,this red-emitting CEGO phosphor exhibits a better thermal stability at higher temperatures(175-250℃,>90%)than typical red K2SiF6:Mn^(4+)and Y203:Eu^(3+)phosphors,and has a remarkable volumetric negative thermal expansion(coefficient of thermal expansion,a=—5.06×10^(-5)/℃,25-250℃).By employing this red CEGO phosphor,a fabricated pc-WLED emits warm white light with colour coordinates(0.364,0.383),a high colour rendering index(CRI=89.7),and a low colour coordinate temperature(CCT=4508 K).These results indicate that this highly efficient red-emitting phosphor has great potential as a red component for pc-WLEDs,opening a new perspective for developing new phosphor materials.
基金financially supported by the National Natural Science Foundation of China(NSFC Nos.51720105015,51932009,51929201,52072349)the Projects for Science and Technology Development Plan of Jilin Province(20210402046GH)the Natural Science Foundation of Zhejiang Province(LR22E020004).
文摘Near-infrared(NIR)-emitting phosphor-converted light-emitting diodes have attracted widespread attention in various applications based on NIR spectroscopy.Except for typical Cr^(3+)-activated NIR-emitting phosphors,next-generation Cr^(3+)-free NIR-emitting phosphors with high efficiency and tunable optical properties are highly desired to enrich the types of NIR luminescent materials for different application fields.Here,we report the Fe^(3+)-activated Sr2−yCay(InSb)1−zSn_(2)zO_(6)phosphors that exhibit unprecedented long-wavelength NIR emission.The overall emission tuning from 885 to 1005 nm with broadened full-width at half maximum from 108 to 146 nm was realized through a crystallographic site engineering strategy.The NIR emission was significantly enhanced after complete Ca^(2+)incorporation owing to the substitution-induced lower symmetry of the Fe^(3+)sites.The Ca_(2)InSbO_(6):Fe^(3+)phosphor peaking at 935 nm showed an ultra-high internal quantum efficiency of 87%.The as-synthesized emission-tunable phosphors demonstrated great potential for NIR spectroscopy detection.This work initiates the development of efficient Fe^(3+)-activated broadband NIR-emitting phosphors and opens up a new avenue for designing NIR-emitting phosphor materials.