Near-infrared excited rare-earth(RE)-doped up-conversion(UC)-luminescent materials have attracted enormous attention because of their unique emission properties,such as narrow emission bands,long luminescence lifetime...Near-infrared excited rare-earth(RE)-doped up-conversion(UC)-luminescent materials have attracted enormous attention because of their unique emission properties,such as narrow emission bands,long luminescence lifetimes,and multiple colors.However,current development of RE-doped luminescent material is hindered by weak and narrowband absorption problems and low photon-conversion quantum efficiencies.In addition to conventional approaches to enhance fluorescence intensity,controlling emission directivity to improve detection efficiency has become a promising approach to obtain higher luminescence brightnesses.In this paper,a self-suspended RE-doped UC luminescent waveguide is designed to realize directional emissions.Benefitting from the special morphology of the crown-like NaYF4:Yb3+/Er3+microparticle,the points contact between the waveguide and substrate can be obtained to decrease energy loss.An attractive UC luminescent pattern accompanied by powerful and controllable directional emissions is observed,and the spatial emission angle and intensity distribution are explored and analyzed in detail by introducing Fourier imaging detection and simulation.This work provides a new method for achieving controllable directional fluorescence emissions and obtaining improved detection efficiency by narrowing emission directivity,which has potential applications in 3-dimensional displays and micro-optoelectronic devices,especially when fabricating self-fluorescence micron lasers.展开更多
Localized surface plasmon has been extensively studied and used for the photocatalysis of various chemical reactions.However,the different contributions between plasmon resonance and interband transition in photocatal...Localized surface plasmon has been extensively studied and used for the photocatalysis of various chemical reactions.However,the different contributions between plasmon resonance and interband transition in photocatalysis has not been well understood.Here,we study the photothermal and hot electrons effects for crystal transformation by combining controlled experiments with numerical simulations.By photo-excitation of Na YF4:Eu^(3+)@Au composite structure,it is found that the plasmonic catalysis is much superior to that of interband transition in the experiments,owing to the hot electrons generated by plasmon decay more energetic to facilitate the reaction.We emphasize that the energy level of hot electrons plays an essential role for improving the photocatalytic activity.The results provide guidelines for improving the efficiency of plasmonic catalysis in future experimental design.展开更多
基金the National Natural Science Foundation of China(Grant Nos.11574190 and 11504224)the National Science Foundation of Shaanxi Province(Grant Nos.2019JQ-142 and 2019JM-441)the Fundamental Research Funds for Central Universities(Grant Nos.GK201701008,201903013,and 2017TS013).
文摘Near-infrared excited rare-earth(RE)-doped up-conversion(UC)-luminescent materials have attracted enormous attention because of their unique emission properties,such as narrow emission bands,long luminescence lifetimes,and multiple colors.However,current development of RE-doped luminescent material is hindered by weak and narrowband absorption problems and low photon-conversion quantum efficiencies.In addition to conventional approaches to enhance fluorescence intensity,controlling emission directivity to improve detection efficiency has become a promising approach to obtain higher luminescence brightnesses.In this paper,a self-suspended RE-doped UC luminescent waveguide is designed to realize directional emissions.Benefitting from the special morphology of the crown-like NaYF4:Yb3+/Er3+microparticle,the points contact between the waveguide and substrate can be obtained to decrease energy loss.An attractive UC luminescent pattern accompanied by powerful and controllable directional emissions is observed,and the spatial emission angle and intensity distribution are explored and analyzed in detail by introducing Fourier imaging detection and simulation.This work provides a new method for achieving controllable directional fluorescence emissions and obtaining improved detection efficiency by narrowing emission directivity,which has potential applications in 3-dimensional displays and micro-optoelectronic devices,especially when fabricating self-fluorescence micron lasers.
基金the National Key Research and Development Program of China(Grant No.2020YFA0211300)the National Natural Science Foundation of China(Grant Nos.92050112,12074237,and 12004233)the Fundamental Research Funds for Central Universities,China(Grant Nos.GK202103010and GK202103018)。
文摘Localized surface plasmon has been extensively studied and used for the photocatalysis of various chemical reactions.However,the different contributions between plasmon resonance and interband transition in photocatalysis has not been well understood.Here,we study the photothermal and hot electrons effects for crystal transformation by combining controlled experiments with numerical simulations.By photo-excitation of Na YF4:Eu^(3+)@Au composite structure,it is found that the plasmonic catalysis is much superior to that of interband transition in the experiments,owing to the hot electrons generated by plasmon decay more energetic to facilitate the reaction.We emphasize that the energy level of hot electrons plays an essential role for improving the photocatalytic activity.The results provide guidelines for improving the efficiency of plasmonic catalysis in future experimental design.
