Microstructure and optical properties of TiO2nanocrystallites–CaTiO3:Pr3+ hybrid thick films

Abstract

Long afterglow CaTiO3:Pr[Formula: see text] ceramic powders were integrated with hydrothermal TiO2nanocrystallites via “doctor-blade” and TiO2-CaTiO3:Pr[Formula: see text] hybrid thick films on FTO substrate were fabricated. Effects of the Pr[Formula: see text] doping level (0.06%, 0.3%) and the CaTiO3:Pr[Formula: see text]/TiO2weight ratio (0.23, 0.92) on the crystallinity, morphologies, optical transmittance and photoluminescence (PL) properties were investigated. Results showed that the crystallinity of the hybrid films originated from both TiO2nanocrystallites and CaTiO3:Pr[Formula: see text] ceramic particles, affected little by the integrating process. The film surface became denser and coarser due to the incorporation of CaTiO3:Pr[Formula: see text] micron/submicron particles, and the film thickness varied little ([Formula: see text][Formula: see text]2.2[Formula: see text][Formula: see text]m). The optical transmittance of the hybrid film decreased sharply ([Formula: see text][Formula: see text]20% for 0.92 incorporation level) due to the scattering effects of the CaTiO3:Pr[Formula: see text] micron/submicron particles to the incident light. All the hybrid films exhibited strong PL at [Formula: see text][Formula: see text]613[Formula: see text]nm when excited with 332–335[Formula: see text]nm, and the film with the Ca[Formula: see text]TiO3:Pr[Formula: see text]/TiO2weight ratio of 0.23 showed the highest emission. In addition, the film exhibited a photoresponce to a broad ultraviolet excitation ranging from 288–369[Formula: see text]nm and a long emission decay time up to 30[Formula: see text]min at 613[Formula: see text]nm, possible for use in the ultraviolet detectors, solar cells and other photoelectrical devices.