Synthesis and up-conversion luminescence of Er3+ and Yb3+ codoped nanocrystalline tetra- (KLaP4O12) and pentaphosphates (LaP5O14)

摘要

The up-converting nanocrystals of KLa0.95Er0.05 and La0.95-xEr0.05YbxP5O14 were prepared using co-precipitation method. The spectroscopic properties of these materials were investigated in a function of Yb3+ concentration. The up-conversion emission, power dependence of emission intensities, and the luminescence decay times were investigated. It was found that the green to red and 2H(11/2) -> 4I(15/2) to S-4(3/2) -> 4I(15/2) emission intensity ratio were strongly affected by the Yb3+ concentration. Moreover, the order of up-conversion emission and threshold power rises up with Yb3-1 concentration for 4S(3/2) I-4(5/2) transition. The luminescence decay time of the S-4(3/2) -> 4I(15/2) emission increases with Yb3+ concentration while the F-4(9/2) -> I-4(15/2) emission is independent of dopant concentration. The influence of the Yb3+ concentration on the up-conversion emission intensities was discussed in terms of concentration dependent hetero looped photon avalanche process. A comparison of the up-conversion properties of KLa(0.95)Er(0.05)YbxP(4)O(12) and La(0.95-x)Er(0.05)sYb(x)PO(14) nanocrystals was presented. (C) 2015 AIP Publishing LLC.