Gamma‐Ray Irradiation Assisted Polyacrylamide Gel Synthesis of Scheelite Type BaWO 4 Phosphors and Its Colorimetric, Optical and Photoluminescence Properties

• Published in: ChemistrySelect (Weinheim) Vol. 5; no. 34; pp. 10599 - 10606
• Main Authors: Tang, Shengnan, Wang, Shifa, Yu, Xianlun, Gao, Huajing, Niu, Xiaowei, Wang, Yong, Zhao, Xinxin, Sun, Guangzhuang, Li, Dengfeng
• Format: Journal Article
• Language: English
• Published: 14.09.2020
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.202002429

Abstract A gamma‐ray irradiation assisted polyacrylamide gel method is used to synthesize the scheelite‐type barium tungstate (BaWO 4 ) phosphors with space group I41/a(88). Various instruments were employed to characterize and reveal the phase purity, microcosmic characteristics, chemical composition, surface micromorphology, colorimetric, optical and photoluminescence properties of BaWO 4 phosphors. The phase structure and functional group analysis showed that the formation temperature of pure BaWO 4 phosphor was 100 °C lower than calcium tungstate (CaWO 4 ) and strontium tungstate (SrWO 4 ). The characterization of particle growth showed that BaWO 4 was easy to grow along (112) and (200) crystal planes. The optical band gap (Eg) value of BaWO 4 first increases and then decreases with the increasing of sintering temperature. The sintering temperature causes the BaWO 4 xerogel to produce a variety of colors from black to white. The photoluminescence spectra showed that two obvious emission peaks at 380 and 415 nm are observed when the excitation wavelength is 334 nm. The former is ascribed to the T 1(2) →A 1(1) transition and the latter could be attributed to the defect energy levels in the BaWO 4 phosphors. The intensity of emission peak at 380 nm decreases with the increasing sintering temperature. The photoluminescence mechanism of scheelite‐type BaWO 4 phosphor was explored on the basis of energy band theory and experimental results.