LAUSR

Abstract A series of crystalline powder samples of K2YF5:1.0%Nd3+, x%Yb3+ (x = 0, 2.0, 5.0 and 8.0) were prepared by hydrothermal synthesis method. The excitation and emission spectra and luminescence decay curves were studied. The decay time of Nd3+ 4D3/2 and 2P3/2 independence on Yb3+ concentration illustrates the absence of direct cross relaxation energy transfer from these two states to Yb3+ in K2YF5. However, the shortening of rising time of Nd3+ 4F3/2 luminescence with Yb3+ concentration reveals the existence of cross relaxation energy transfer from Nd3+ to Yb3+, the potential energy transfer process from Nd3+ (4G9/2→4F3/2) to Yb3+ (2F7/2→2F5/2) has been proposed. Furthermore, the second step energy transfer from Nd3+ (4F3/2→4I9/2) to Yb3+ (2F7/2→2F5/2) has been verified and the transfer efficiency of 89% from Nd3+ 4F3/2 state to Yb3+ has been obtained in K2YF5:1.0%Nd3+, 8.0%Yb3+. The mechanism responsible for the efficient energy transfer is electric dipole-dipole interaction.