Full-Color Inorganic Carbon Dot Phosphors for White-Light-Emitting Diodes

TLDR: In this paper, the authors proposed an approach toward realization of full-color emissive CDots from two common precursors, citric acid and urea, through employing three different solvents (water, glycerol, and dimethylformamide) and their combinations in a solvothermal synthesis.

Abstract: Light-emitting carbon dots (CDots) are widely investigated due to their distinct merits. However, it is still a challenge to modulate their bandgap emissions and conquer their aggregation-induced luminescence quenching to achieve full-color highly emissive CDot-based phosphors. Herein, this study proposes an approach toward realization of full-color emissive CDots from two common precursors, citric acid and urea, through employing three different solvents (water, glycerol, and dimethylformamide) and their combinations in a solvothermal synthesis. Employing sodium silicate solution, this study further demonstrates the microwave-assisted method allowing to incorporate CDots into a silica network, which effectively prevents aggregation of CDots and results in strongly luminescent full-color inorganic CDot phosphors with photoluminescence quantum yields of 30–40%. Through deposition of the red- and green-emitting CDot phosphors on blue-emitting InGaN chips, white-light-emitting diodes are fabricated with Commission Internationale de L'Eclairage of (0.34, 0.31) and the color rendering index of 82.4, indicating their promising application for solid-state lighting.