Abstract: NaTaO₃ and Bi³⁺ doped NaTaO₃ were prepared by conventional high temperature solid state reactions and characterized by the photoluminescence spectroscopy. The luminescence characterization of NaTaO₃ is sensitive to its preparation condition. Under the condition of Na scarcity, two luminescence bands of 515 nm and 745 nm are observed in the photoluminescence spectra, which are ascribed to the antisite defects of Ta_Na.... and V_Na` defects, respectively. Under the condition of Na enough, the luminescence band shifts to about 460 nm, which are originated from the intrinsic tantalate groups. The introduction of Bi³⁺ causes the emission band shifts from 515 to 455 nm, namely, the Ta_Na.... defects are replaced by Bi_Na.. defects and the luminescence characterization of NaTaO₃ is shift to the direction of a higher n(Na)/n(Ta) ratio. The present work also demonstrates that the photoluminescence spectroscopy is a powerful technique to characterize the defect chemistry in semiconductor materials and it is especially useful in the study of photocatalysts.

Key words: Photoluminescence spectroscopy, NaTaO₃, NaTaO₃∶Bi³⁺