Liu Wen, Hao Zhendong, Zhang Liangliang, Wu Hao, Zhang Xia, Luo Yongshi, Pan Guohui, Zhao Haifeng, Fu Zuoling, Zhang Jiahua
State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences , 3888 Eastern South Lake Road, Changchun 130033, China.
University of Chinese Academy of Sciences , Beijing 100049, China.
Inorg Chem. 2017 Oct 16;56(20):12291-12296. doi: 10.1021/acs.inorgchem.7b01725. Epub 2017 Sep 25.
Near-infrared (980 nm) to near-infrared (800 nm) and blue (490 nm) upconversion has been studied in 0.2% Tm and 10% Yb codoped LuO-ZrO solid solutions as a function of the ZrO content in the range of 0-50%, prepared by a high-temperature solid-state reaction. The continuous enhancement of upconversion luminescence is observed with increasing ZrO content up to 30%. Analyses of the Yb emission intensity and lifetime indicate enlarged absorption of a 980 nm excitation laser and enhanced energy transfer from Yb to Tm with the addition of ZrO. The spectrally inhomogeneous broadening of the dopants in this disordered solid solution is considered to play the main role in the enhancement by providing better matches with the excitation laser line and increasing the spectral overlap for efficient energy transfer from Yb to Tm. In addition, the inhomogeneous broadening is also validated to improve energy migration among Yb ions and energy back transfer from Tm to Yb. Hence, it is understandable that a drop in the upconversion luminescence intensity occurs as the concentration of ZrO is further increased from 30% to 50%. This work indicates the possibility of disordered crystals to achieve intense upconversion luminescence for biological and optoelectronic applications.
