One‐Step Synthesis of Silica‐Coated Carbon Dots with Controllable Solid‐State Fluorescence for White Light‐Emitting Diodes

Carbon dots (CDots)-based solid-state luminescent materials have important applications in light-emitting devices owing to their outstanding optical properties. However, it still remains a challenge to develop multiple-color-emissive solid-state CDots, due to the serious self-quenching of the CDots in the aggregation or solid state. Herein, a one-step synthesis of multiple-color-emissive solid-state silica-coated CDots (silica/CDots) composites by controlling CDots loading fraction and composite morphology to realize the adjustment of emitting color is reported. The emission of resultant silica/CDots composites shifts from blue to orange with the photoluminescence quantum yields of 57.9%, 34.3%, and 32.7% for blue, yellow, and orange emitting, respectively. Furthermore, the yellow emitting silica/CDots composites exhibit an excellent fluorescence thermal stability, and further have been applied to fabricate white-light-emitting devices with a high color rendering index of above 80.