Energy transfer and cross-relaxation induced multicolor upconversion emissions in Er3+/Tm3+/Yb3+ doped double perovskite La2ZnTiO6 phosphors

Investigation on the bright and stable upconversion (UC) phosphors with multicolor emissions is fundamental and significant for the frontier applications of display and temperature probe. Here, diverse emitting colors with blue, cyan and yellowish green, which are caused by the energy transfer and cross -relaxation processes, are obtained by altering Er3+, Tm3+ and Yb3+ concentrations in Er3+ singly, Er3+-Tm3+ - Yb3+ co- and tri-doped double perovskite La2ZnTiO6 (LZT) phosphors synthesized by a simple solid-state reaction. In addition, excellent infrared emission at 801 nm located at "first biological window" is collected in Tm3+ Yb(3+ )co-doped phosphors. Meanwhile, the temperature sensing properties based on the thermally coupled levels (H-2(1)/2/S-4(3/2)) of Er3+ ions were analyzed from 298 to 573 K of LZT:0.15Er(3+)/0.10Yb(3+) phosphor, demonstrating that the maximal sensitivity value is about 56 x 10( -4)K(-1) at 448 K. All these results imply that this kind of UC material has potential applications in display, bioimaging and optical device. (C) 2020 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.