Role of Li+ ion in improved crystallization and the luminescence enhancement of up and down conversion process in Er3+/Yb3+ doped in Y4O(OH)9NO3 and Y2O3 nanoparticles

Abstract

Here, the up-and down-conversion emissions enhancement in Er 3+ /Yb 3+ /Li + co-doped Y 4 O(OH) 9 NO 3 and Y 2 O 3 nanoparticles was studied in function of the calcination temperature. Tri-doped Y 4 O(OH) 9 NO 3 nanophosphors were synthesized by the hydrothermal method and then calcined to yield Y 2 O 3 nanocrystalline structures. The phase evolution from Y 4 O(OH) 9 NO 3 to Y 2 O 3 was investigated by XRD analysis, and the quantification of Li + species in the nanoparticles lattice was done by FTIR. Both techniques allow explaining the photoluminescence enhancement in terms of the calcination temperature required to achieve optimum lithium incorporation. SEM analysis was used to monitor changes in the morphology with the thermal treatment temperature. The resulting photoluminescence emission spectra of the Er 3+ /Yb 3+ doped Y 4 O(OH) 9 NO 3 and Y 2 O 3 nanocrystals were composed of emission bands associated with the Er 3+ 2 H 11/2 , 4 S 3/2 → 4 I 15/2 (green), 4 F 9/2 → 4 I 15/2 (red), and 4 I 13/2 → 4 I 15/2 (infrared) intraelectronic transitions, and its relative contribution was found to be sensitive to the calcination temperature. Thus, tunable color emission from yellowish-orange to yellow-green light with a color temperature of 2581–4433 K upon 980 nm excitation, respectively, was observed.