点击次数：

论文类型：期刊论文

发表时间：2014-08-01

发表刊物：18th International Conference on Dynamical Processes in Excited States of Solids (DPC)

收录刊物：SCIE、EI、CPCI-S

卷号：152

页面范围：218-221

ISSN号：0022-2313

关键字：Yb3+; Er3+; Gadolinium tungstate; Phosphor; Up-conversion; Infrared emission

摘要：Yb3+, Er3+ co-doped Gd-2(WO4)(3) and Gd2WO6 phosphors have been prepared using co-precipitation method and characterized by X-ray diffraction and optical and infrared spectroscopy. Different processes of upconverted transitions have been observed in the two hosts. Strong green and red emissions have been respectively detected in Gd-2(WO4)(3):Yb3+, Er3+ and Gd2WO6:Yb3+, Er3+ upon excitation at 980 nm, suggesting that the excited state absorptions from I-4(11/2) and I-4(13/2) of Er3+ dominate the excitation processes in the two systems, respectively. The different excitation processes of the up-conversion are related to structural difference. The existence of near-neighbor rare earth ion-pair in Gd2WO6 may promote the depopulation of F-4(7/2) through a cross relaxation of E-4(7/2)-> F-4(9/2) and I-4(11/2)-> F-4(9/2), yielding the dominating red emission in Gd2WO6. On the other hand, intense near infrared emissions have been observed from two Stark splitting groups of I-4(13/2) to I-4(15/2) at 1540 nm and 1490 nm, respectively, in both hosts. However, the infrared emission is dominated by the lower state at 1540 nm in Gd2WO6, resulting in an efficient ESA, due to the better energy difference matching, from the lower state to E-4(9/2) that gives red emission. Concentration dependence of the intensity ratio of green to red emissions is also studied and energy transfer between Yb3+ and Er3+ ions analyzed. (C) 2013 Elsevier B.V. All rights reserved.