White light emission and energy transfer mechanism of LaOCl:Tb3+/Sm3+ with 3D umbrella-like structure

Abstract

A class of Tb3+, Sm3+ activated LaOCl samples possessing 3D umbrella-like structure were successfully synthesized by a conventional hydrothermal approach with further sintering and chlorination processes. The energy transfer process occurs in co-doped phosphors. The energy transfer properties were justified via spectral overlapping joining emission spectra and luminescent decay times. Meanwhile, the energy transfer mechanism is determined for a dipole-dipole interaction, and the critical distance and energy transfer efficiency between Tb3+ and Sm3+ are also calculated. Emission spectra of Tb3+/Sm3+ co-activated phosphors exhibit red emissions from Sm3+ transition, blue and green emissions from Tb3+ transition. Stimulated by near-ultraviolet light, an emission hue from cool white light to warm white light is acquired via conditioning the molar ratio of Tb3+/Sm3+ in the LaOCl host. These results manifest that the as-synthesized samples can be good candidates for white light emitting diodes (w-LEDs) with great potential.