Rare-earth free sensitizer in NaLuCrF_4:Er upconversion material

作     者：Bui The Huy Zayakhuu Gerelkhuu The-Long Phan Ngo Tran Yong-IllLee 

作者机构：Institute of Research and Development Duy Tan University Department of Chemistry Changwon National University Department of Physics Hankuk University of Foreign Studies 

出 版 物：《Journal of Rare Earths》 (稀土学报（英文版）)

年 卷 期：2019年第37卷第4期

页      面：345-349页

核心收录：

学科分类：081702[工学-化学工艺] 08[工学] 0817[工学-化学工程与技术] 

基　　金：supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF-2017RIA2B4006388 NRF-2017R1D1A3B03035530) 

主　　题：Upconversion materials Sensitizer Transition metal ions Magnetism 

摘      要：Upconversion phosphors are known as a material system that can convert near-infrared light into visible/ultraviolet emissions by sequentially absorbing multiple photons. The studies on upconversion materials often use two rare earth(RE) ions as a sensitizer-activator pair. We investigated the influences on luminescence intensity depending on Cr-doping content(x) of hexagonal NaLu_(0.98-x)Cr_xF4 Er_(0.02)(x = 0-0.9)upconversion material by substituting Lu^(3+) ions with Cr^(3+)in the absence of Gd^(3+). The change in upconversion luminescence intensity appears with saddle-like shape. We suggest that Cr^(3+) ions play the dual role as a constituent in host lattice and a sensitizer in the upconversion process. Optimal conditions for gaining the strongest upconversion emission correspond to x = 0.3-0.5, where there are effective energy transfers between Cr^(3+) and Er^(3+) ions and Cr-Er dimers. Apart from these values, the emission intensity decreases rapidly which can be ascribed to the absence of multiple-photon absorption for the case of low Cr^(3+) contents, and to the coupling between Cr^(3+) and/or Er^(3+) ions for the case of high Cr^(3+)contents. Magnetization and electron-spin-resonant measurements were performed to understand the correlation between the optical and magnetic properties.