Photoluminescence quenching and photocatalytic enhancement of Pr-doped ZnO nanocrystals

This work reports the synthesis of novel praseodymium (Pr)-doped ZnO nanocrystals with excellent photocatalytic activity through modified solid-state reaction route. The impacts of doping on the wurtzite hexagonal structure are analysed with X-ray diffraction (XRD) and Raman spectroscopy. The production of defect levels and the formation of Urbach energy within the system are confirmed using photoluminescence (PL) techniques and UV/Vis diffuse reflectance spectroscopy, respectively. The linear relationship between Urbach energy and band gap energy is elucidated from UV/Vis spectroscopy analysis. The changes happened to morphology by doping were tackled using scanning electron microscopy (SEM). The concentration quenching effect of PL emission with Pr doping is explained in detail. A three-fold enhancement in the photocatalytic activity was achieved with optimum Pr incorporation in ZnO. This work successfully correlated PL quenching and enhanced photocatalytic activity with the defect production happened in ZnO system on Pr doping. The practical applicability of the photocatalyst was confirmed with a stability test.