The effect of ion radius on luminescence for alkali ions doping in Y2O3: Yb3+/Ho3+ thin film

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 286; p. 121934
• Main Authors: Xu, Boxu, Song, Chao, Huang, Rui, Song, Jie, Zhang, Yi, Lin, Zhenxu, Guo, Yanqing, Lin, Shaomin, Song, Jun, Liu, Juncheng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.02.2023
• Subjects: Alkali ion; Color tunable; Emission enhancement; Thin film; Up conversion; Y2O3; Up conversion; Color tunable; Y2O3; Emission enhancement; Alkali ion; Thin film
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2022.121934

[Display omitted] •Li+, Na+, K+ and Rb+ enhanced emissions of Yb3+/ Ho3+ doped Y2O3 films notably.•Li+ involves three factors that enhance luminescence, the other through two.•Li+ adjusted color coordinate towards the 539 nm direction, K+ towards to 550 nm.•Na+ and Rb+ can provide a color-stable emission enhancement. In this paper, alkali ion (Li+ Na+ K+ and Rb+)-doped Y2O3:Yb3+/Ho3+ up conversion films were prepared using the sol–gel method. The structures of the films were studied by using X-ray diffraction, scanning electron microscopy, and Raman spectroscopy. A series of high-quality thin films with good crystallization were prepared. For all samples, two emission bands were observed: green emission at 539 (550) nm and red emission at 664 nm, which can be attributed to 5F4 (5S2)→5I7 and 5F5→5I8, respectively. The green emission is dominant, and the red emission is extremely weak. The effect of each alkali-ion dopant on the emission and color adjustment of samples was investigated. The green emission intensity is increased by a factor of 6.33 (Li), 2.03 (Na), 4.82 (K) and 1.92 (Rb) with increasing alkali-ion doping concentration, and red emission is increased by a factor of 7.80 (Li), 1.92 (Na), 4.78 (K) and 1.90 (Rb). The extreme value appears earlier with increasing ion radius. Li+ doping boosts luminescence in three ways, and the other alkali ions affect the light emission in two ways. Li+ doping and K+ doping can be used to adjust the color coordinates towards the 539 nm and 550 nm directions, respectively. Na+ and Rb+ doping can enhance emission with a stable color. This means that each alkali ion is a suitable choice as a color-regulating ion and can play a role in the regulation of luminescence.