NaTaO_3及NaTaO_3∶Bi^(3+)光催化剂的光致发光光谱研究

Photoluminescence Spectroscopy of NaTaO_3 and NaTaO_3∶Bi^(3+) Photocatalysts

采用光致发光光谱技术对一系列不同条件下制备的NaTaO3及不同掺杂量的NaTaO3∶Bi3+进行了研究.结果表明,NaTaO3的发光性质与其制备条件密切相关在钠离子不足的条件下合成的样品,其发光带主要位于515和745nm左右;而在钠离子充足条件下合成的样品,其发光带位于460nm左右,随着n(Na)/n(Ta)的降低,发光带向长波长方向移动;掺入Bi3+之后,其发光峰由515nm移至455nm,随着Bi3+掺入量的增加,455nm的发光带强度减弱.515nm的发光带与替位缺陷Ta.N.a..相关;745nm的发光带与VN`a缺陷相关;而460nm的发光带与本征TaO6基团相关.将Bi3+掺入到钽酸钠样品,TaN..a..由BiN..a替代,相应的发光带向高的n(Na)/n(Ta)方向移动,从而呈现出本征TaO6基团的发光带.

NaTaO3 and Bi^3＋ 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 Bi^3＋ causes the emission band shifts from 515 to 455 nm, namely, the Ta Na… defects are replaced by Bi Na… defects and tire 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.