Interface/defect-tuneable macro and micro photoluminescence behaviours of trivalent europium ions in electrospun ZrO2/ZnO porous nanobelts
It was demonstrated that suitable interfaces between two materials can enhance the separation of photogenerated carriers. In this study, ZrO2/ZnO interfaces with type I structure were designed and prepared by the electrospinning technique. The obtained ZrO2/ZnO:Eu3+ (ZZOE) composites are highly porous in the form of nanobelts with width of 600–700 nm, comprising ZnO and ZrO2 nanocrystals, and the Eu doping can hinder the t–m phase transition of ZrO2. By tuning the annealing temperature, the inner stress and defects can be well controlled to improve the photoluminescence (PL) of the ZZOE porous nanobelts. Macro- and micro-PL spectra indicated that the body oxygen vacancies benefit the PL from Eu3+ ions, whereas the surficial ones do not. The optimal parameters for the preparation of ZZOE porous nanobelts were also investigated. Finally, a charge transfer mechanism was proposed to illuminate the PLs from the ZZOE porous nanobelts.