Bi4-xNdxTi3O12 (x = 0.25, 0.5, 0.75, 1.00) nanocrystalline was prepared by modified sol-gel method. The powders crystallized well after annealing at 830οC for 30 min in air. Phase composition and optical properties of Bi4-xNdxTi3O12 nanocrystalline were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence (PL) spectra and ultraviolet-visible (UV-Vis) absorption spectra. In PL spectra, the major up-converted band observed at 534 nm (green) originated from the 4G7/2 4I9/2 excited state absorption (ESA) when exciting at 800 nm. It was also found that with increasing of x value the luminous intensity decreased because of different location of Nd3+ substitution. The optical energy band gap of the Bi3.5Nd0.5Ti3O12 nanocrystalline was found to be 3.17 eV by Tauc equation. The up-conversion mechanisms in the doped system will be discussed by analyzing the energy level structures of Nd3+.

Keywords: Bi4Ti3O12, Sol-gel method, Photoluminescence, Up-conversion