标题：Radiative/Nonradiative Recombination Affected by Defects and Electron-Phone Coupling in CdWO4 Nanorods
作者：Zhang, Cuiling; Guo, Donglin; Xu, Weina; Hu, Chenguo; Chen, Yanxue
作者机构：[Zhang, Cuiling; Guo, Donglin; Xu, Weina; Hu, Chenguo] Chongqing Univ, Dept Appl Phys, Chongqing 400044, Peoples R China.; [Chen, Yanxue] Shandong U 更多
通讯作者地址：[Hu, CG]Chongqing Univ, Dept Appl Phys, Chongqing 400044, Peoples R China;[Chen, YX]Shandong Univ, Sch Phys, Jinan 250100, Peoples R China.
来源：JOURNAL OF PHYSICAL CHEMISTRY C
摘要：Tungstates are important photoluminescence (PL) materials owing to their unique luminescence center. However, radiative or nonradiative recombination affected by defects and electron-phone coupling have not been well understood. In this paper, we have synthesized CdWO4 nanorods and studied its temperature-dependent PL spectrum from 20 to 300 K Theoretical calculations demonstrate that Cd vacancy (V-cd) and O vacancies (V-o(0), V-o(1+), and Vo(2+)) induce extra levels in the band gap, by which the V-cd, V-o(0), and V-o(1+) defects mainly contribute to the absorption in 0-4 eV region, while V-o(2+) causes the emission bands peaked at 490 nm in PL spectrum. Because of the broken symmetry of octahedron two possible types of lowest unoccupied molecular orbital (LUMO) appear and the transitions from the each LUMO to the highest occupied molecular orbital (HOMO) contribute to the emission at about 410 and 436 nm. The emission intensity of the peaks decreases with an increase in temperature due to the thermal quenching by nonradiative recombination. This work insights into the understanding of physical nature of emission and presents a detailed analysis of the electron transition behaviors in the wolframite-type monoclinic CdWO4, which can be used not only to explain the photoluminescence mechanism of CdWO4, but also for the structure design to obtain better emission properties in tungstates.