Structural and optical properties of nanosized ZnO/ZnTiO_3 composite materials synthesized by a facile hydrothermal technique

摘要

We report the structural and optical properties of ZnO/ZnTiO_3 nanocomposites synthesized at various calcination temperatures ranging from 500 to 900 °C by a simple hydrothermal process without using any dispersant agents. The XRD results reveal the coexistence of ZnO and ZnTiO_3 phases when calcined at 600-900 °C, however, only pure ZnO phase appears when calcined at 500 °C for 1 h. Functional groups were identified by FTIR spectroscopic technique, which exhibit characteristic infrared absorption bands of ZnO/ZnTiO_3 nanocomposites. The synthesized composites have absorbance at a wavelength of 300 and 370 nm and the band gap energy of the ZnO/ZnTiO_3 nanocomposite system is tuned by varying the calcination temperature. The morphology of the particles were visualized by TEM analysis which shows the morphology changing from irregular particles to uniform spherical, rod and cubic structures while increasing the temperature from 500 to 900 °C. All the samples show interesting broad blue and green emission at about 490 and 530 nm. Incidentally, the emission intensity of the composite ZnO/ZnTiO_3 phase is stronger than that of pure ZnO phase prepared at 700 and 900 °C.