Carbon dots embedded in lead-free luminescent metal halide crystals toward single-component white emitters

The development of single-component white emitters for white light-emitting diodes (WLEDs) remains challenging. Herein, a rare earth-free white light-emitting composite is developed by assembling blue-emitting carbon dots (CDs) and yellow-emitting Cs2InCl5·H2O:Sb3+ metal halide crystals via a facile liquid-liquid diffusion-assisted crystallization approach. The encapsulation mechanism is then analyzed. Depending on the ratios of blue/yellow emitters, these luminescent composites exhibit white light emission with tunable cold and warm hues. The composites also possess prominent ultraviolet resistance, thermal tolerance, and good stability at about 200°C. By employing such "CDs in metal halide" composites as a converter, a WLED is successfully fabricated with a high color rendering index of 93.6, benefiting from the assembled blue and yellow broadband emission. With this strategy, the developed composites show great promise in next-generation WLED lighting.