Influence of annealing temperature on morphological and photocatalytic activity of sputter-coated CaCu3Ti4O12 thin film under ultraviolet light irradiation

CaCu3Ti4O12 (CCTO) thin films were deposited by radio frequency (RF) magnetron sputtering and subsequently annealed at 300, 400, 500, or 600 degrees C. The XRD analysis showed that the amorphous CCTO thin film transformed to more crystallite structure as the annealing temperature increased to 600 degrees C. Generally, the average crystallite size, grain size and roughness of the thin films increased with increasing annealing temperature. Photocatalytic activities of these thin films were evaluated by the effectiveness of Rhodamine B (RhB-C28H13ClN2O3) removal from solution under ultraviolet (UV) light illumination. In particular, the CCTO thin film annealed at 600 degrees C exhibited the highest photocatalytic activity, where it removed 67.4% of RhB dye in 4 h, at a rate constant of 0.217 min(-1). This observation was ascribed to its higher crystallinity and larger grain size of CCTO thin film annealed at 600 degrees C.