Facile fabrication of color-tunable and white light emitting nano-composite films based on layered rare-earth hydroxides

Abstract

A novel class of color-tunable and white light emitting hybrid phosphors based on efficient energy-transfer between Tb³⁺ and Eu³⁺ and the rich interlayer chemistry of the layered rare-earth hydroxides (LRHs) were successfully designed and assembled. Besides, flexible luminescent materials have attracted an extensive amount of interest owing to their broad application in optoelectronic devices. Therefore, novel transparent color-tunable nano-composite film devices have been fabricated facilely by using a solvent-casting method based on the compatibility between the LRH hybrid phosphors modified by organic sensitizers and poly(methyl methacrylate) (PMMA) in this paper. A full interpretation to the interaction between the host and guest of the hybrid phosphors was given, the luminescence intensity of hybrid phosphors was significantly enhanced through a cascaded energy-transfer mechanism from the host to Tb³⁺via organic sensitizers, precisely as induced by the synergistic effect of host and guest. And in the nano-composite films, PMMA acted as a co-sensitizer and improved the optical properties of hybrid phosphors, thus the photoluminescence quantum yield of the films more than doubled compared with that of hybrid phosphors. These findings may open up new avenues for the exploration of hybrid phosphors based on LRHs and fabrication of color-tunable emitting nano-composite films, which can serve as promising materials for use in various optical devices. And the proposed facile synthetic strategy can be easily extended to the synthesis of other highly efficient rare-earth hybrid phosphors.