Synergistic effect of crystal structure and concentration quenching on photoluminescence of Er³⁺ doped upconversion nanocrystals

蔡灿英^1,2，靳彦林^1,2，杨奇斌^1,2，聂晓书^1,2，刘云新³

1. Faculty of Materials, Optoelectronics and Physics, Xiangtan University2. Key Laboratory of Low Dimensional Materials and Application Technology, Xiangtan University, Ministry of Education3. Department of Physics and Electronic Science, Hunan University of Science and Technology

摘 要：YbF_2.357, YbF₃, Ba₂ YbF₇, and Ba ₂ upconversion nanocrystals doped with emitter Er³⁺ ion were synthesized in the same solvent system just with changing the molar ratio of Ba²⁺ to Yb³⁺ in the precursor, which corresponed to the crystal phases of rhombohedral, orthorhombic, tetragonal, and cubic, respectively. All the samples emitted both 660 nm red light and 543/523 nm green light which originated from Er³⁺-4fⁿ electronic transitions ⁴F_9/2-⁴I_15/2 and ⁴S_3/2/²H_11/2-⁴I_15/2, respectively. It was worth mentioning that YbF 3:Er³⁺, Ba₂ YbF₇:Er³⁺, and BaF₂:Er³⁺ could emit dazzlingly bright light even under the excitation of a 980 nm CW laser with output power of 0.1 W. Upconversion emission mechanism analysis indicated that the intensity ratio of red to green light highly depended on the synergistic effect of crystal structure, concentration quenching, and particle size, but were not sensitive to crystallinity as previously reported for NaL nF₄（Ln=lanthanide）.

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