Morphology engineering of dual-emissive copper-based perovskites for stable blue LED devices

Abstract

Copper-based ternary halide composites have garnered significant attention for their exceptional chemical stability and optical properties. Here, we report the one-step synthesis of dual-emissive Cs₃Cu₂I₅:CsI perovskite nanocrystals (NCs) via a facile anti-solvent method. Under 295 nm excitation, these NCs exhibit blue emission centered at 450 nm, while 350 nm excitation induces violet emission peaking at 427 nm. The material demonstrates a high photoluminescence quantum yield (PLQY >55 %) and remarkable stability (>30 days in ethanol). Morphological evolution from needle-like to rod-like and irregular bulky to well-defined cubic structures was achieved by precisely modulating precursor stoichiometry and reaction temperature. Furthermore, we fabricated highly stable blue LEDs based on Cs₃Cu₂I₅:CsI perovskite, achieving CIE 1931 chromaticity coordinates of (0.20, 0.25). The devices retained 90.3 % of initial luminance after 192 h of continuous operation.