Cyan-emitting Eu(II)-based hybrid bromides luminescence materials for full-spectrum lighting

Low-dimensional hybrid metal halides have recently gained prominence as next-generation luminescent materials owing to their structural tunability, abundant spectral characters and unique emission mechanisms. Herein, we designed and synthesized three emerging zero-dimensional rare-earth Eu(II)-based hybrid bromides with cyan emission originated from 5d-4f transition of Eu(II). Their photoluminescence quantum yields (PLYQs) are enhanced by molecular-dimensionality-engineering, and the optimized (Me 4 P)EuBr 3 (Me 4 P = tetramethylphosphonium) with a high PLQY of 96.1% shows a narrow emission band peaking at 495 nm with a full width at half maxima of 45 nm upon 390 nm excitation. The as-fabricated white light-emitting diodes (WLED) device based on (Me 4 P)EuBr 3 , commercial K 2 SiF 6 :Mn 4+ and YAG:Ce 3+ , and a 460 nm blue GaN chip achieves a high color rendering index of 92.2. This work not only establishes the structural design and innovation of a new family of hybrid rare-earth halides for efficient photoluminescence, but also provides new phosphor materials for full-spectrum WLED.