Polymer-encapsulated UV-curable stacked prismatic layers of all-halide phosphor composites for white luminescence

Perovskite halide nanocrystals have been actively investigated for use in white-luminescence photonic devices. Herein, a remote phosphor-layered composite consisting of all-halide red and green nanocrystals embedded in an ultraviolet (UV)-cured matrix is proposed as a facile way to create competitive white luminescence. Alternating stacks of cast halide layers with controlled concentration and thickness yielded true white luminescence characteristics when the halide layers were combined with a bottom blue chip. Specifically, the adjusted prismatic pattern for the red halide layer was found to effectively strengthen the emission of white luminescence. In particular, a phosphor-stacked structure of green and red layers with a 9-μm-pitch prismatic pattern resulted in an enhanced luminous efficacy of ∼54.4 lm W⁻¹, which is higher than those of a non-prismatic layer or a larger pitch pattern. Encapsulating both sides of the halide layers with polydimethylsiloxane (PDMS) maintained very effectively the luminescence of the halide layers over the exposure of 300 h.