ZnO nanowires/YAG:Ce functional heterostructure coatings with tunable optical properties

[摘要] Luminescent ZnO nanowires (NWs)/YAG:Ce heterostructure coatings have been elaborated by impregnating cheap hydrothermally-grown ZnO NWs array with ground commercial YAG:Ce nanoparticles (NPs). TEM and photoluminescence quantum yield measurements have been used to make YAG:Ce NPs suitable for soaking within the ZnO NWs. Structural, morphological and optical studies of functional nanocomposite coatings have evidenced an optimal amount of YAG:Ce allowing the visible photoluminescence signal of ZnO NWs nearly to triple whereas slight red shift accompanied by an enlargement on the long wavelength side has been observed for YAG:Ce emission. These phenomena have been explained through the existence of structural defects on ZnO NWs surface and emission mechanisms implying either scattering effects or the passivation of NWs surface by YAG:Ce NPs. Furthermore, an energy diagram involving different structural defects of ZnO NWs as well as Ce3+ ions energy levels has been built from excitation and emission spectra and from decay curves recorded monitoring the orangered emission of ZnO. The elaborated heterostructure functional coatings have proved to exhibit tunable optical properties in terms of spectral distribution playing on the excitation source. Hence, they appear as a smart way for developing LEDs-based devices with flexible photometric parameters for a broader range of optical applications. (C) 2020 Elsevier B.V. All rights reserved.

[发布日期] 2020-11-25

[关键词] Functional coatings;LEDs;Light extraction;Phosphors;Luminescent heterostructures