Chalcogenide quantum dots(QDs)are established as promising materials for white-light-emitting applications because of their wide surface defect emission.However,the limited understanding of the origin of defect emissi...Chalcogenide quantum dots(QDs)are established as promising materials for white-light-emitting applications because of their wide surface defect emission.However,the limited understanding of the origin of defect emission poses challenges in attaining efficient white-light emission.Herein,we sought to introduce high pressure to strengthen the interaction between different types of ligands and QDs,as well as enable in situ observation of surface trap passivation that contributes to emission control.Under pressure,both defect emission and band-edge emission in the CdS QDs could be selectively enhanced by more than an order of magnitude through treatment with X-type and Z-type ligands,respectively.Our findings identified that surface hole traps predominantly contributed to defect emission,whereas nonradiative recombination was primarily associated with surface electron traps.Our goal was to service ambient science through high-pressure research.Thus,based on this proposed mechanism,an energy-saving“neutral”white light with a human-eyefriendly color rendering index of 86 was achieved by tuning the defect emission through further elimination of surface Cd sites.This study endowed high pressure as an efficient tool to elucidate the defect origin of chalcogenide QDs under ambient conditions,paving the way for precise control over white-light emission through materials design application in solid-state lighting.展开更多
Excitation power and temperature-dependent photoluminescence（PL） spectra of the ZnTe epilayer grown on（100）Ga As substrate and ZnTe bulk crystal are investigated. The measurement results show that both the structu...Excitation power and temperature-dependent photoluminescence（PL） spectra of the ZnTe epilayer grown on（100）Ga As substrate and ZnTe bulk crystal are investigated. The measurement results show that both the structures are of good structural quality due to their sharp bound excitonic emissions and absence of the deep level structural defect-related emissions. Furthermore, in contrast to the ZnTe bulk crystal, although excitonic emissions for the ZnTe epilayer are somewhat weak, perhaps due to As atoms diffusing from the Ga As substrate into the ZnTe epilayer and/or because of the strain-induced degradation of the crystalline quality of the ZnTe epilayer, neither the donor–acceptor pair（DAP） nor conduction band-acceptor（e–A） emissions are observed in the ZnTe epilayer. This indicates that by further optimizing the growth process it is possible to obtain a high-crystalline quality ZnTe heteroepitaxial layer that is comparable to the ZnTe bulk crystal.展开更多
基金supported by the National Key R&D Program of China(grant no.2023YFA1406200)the Jilin Provincial Science&Technology Development Program,China(grant no.20220101002JC)+2 种基金the National Science Foundation of China(grant no.12174144)Young Elite Scientists Sponsorship Program of the China Association for Science and Technology(CAST,grant no.2022QNRC001)the Fundamental Research Funds for the Central Universities.This work was mainly performed at BL15U1 at the Shanghai Synchrotron Radiation Facility(SSRF).
文摘Chalcogenide quantum dots(QDs)are established as promising materials for white-light-emitting applications because of their wide surface defect emission.However,the limited understanding of the origin of defect emission poses challenges in attaining efficient white-light emission.Herein,we sought to introduce high pressure to strengthen the interaction between different types of ligands and QDs,as well as enable in situ observation of surface trap passivation that contributes to emission control.Under pressure,both defect emission and band-edge emission in the CdS QDs could be selectively enhanced by more than an order of magnitude through treatment with X-type and Z-type ligands,respectively.Our findings identified that surface hole traps predominantly contributed to defect emission,whereas nonradiative recombination was primarily associated with surface electron traps.Our goal was to service ambient science through high-pressure research.Thus,based on this proposed mechanism,an energy-saving“neutral”white light with a human-eyefriendly color rendering index of 86 was achieved by tuning the defect emission through further elimination of surface Cd sites.This study endowed high pressure as an efficient tool to elucidate the defect origin of chalcogenide QDs under ambient conditions,paving the way for precise control over white-light emission through materials design application in solid-state lighting.
基金Project supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20120131110006)the Key Science and Technology Program of Shandong Province+10 种基金China(Grant No.2013GGX10221)the Key Laboratory of Functional Crystal Materials and Device(Shandong UniversityMinistry of Education)China(Grant No.JG1401)the National Natural Science Foundation of China(Grant No.61306113)the Major Research Plan of the National Natural Science Foundation of China(Grant No.91433112)the Partnership Project for Fundamental Technology Researches of the Ministry of EducationCultureSportsScience and TechnologyJapan
文摘Excitation power and temperature-dependent photoluminescence（PL） spectra of the ZnTe epilayer grown on（100）Ga As substrate and ZnTe bulk crystal are investigated. The measurement results show that both the structures are of good structural quality due to their sharp bound excitonic emissions and absence of the deep level structural defect-related emissions. Furthermore, in contrast to the ZnTe bulk crystal, although excitonic emissions for the ZnTe epilayer are somewhat weak, perhaps due to As atoms diffusing from the Ga As substrate into the ZnTe epilayer and/or because of the strain-induced degradation of the crystalline quality of the ZnTe epilayer, neither the donor–acceptor pair（DAP） nor conduction band-acceptor（e–A） emissions are observed in the ZnTe epilayer. This indicates that by further optimizing the growth process it is possible to obtain a high-crystalline quality ZnTe heteroepitaxial layer that is comparable to the ZnTe bulk crystal.
