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.