High-brightness electroluminescent white light-emitting diodes based on solution-processable, yellow-emissive carbon quantum dots

Abstract

The realization of electroluminescent light-emitting diodes (LEDs) based on carbon quantum dots (CQDs) holds great potential for developing solid-state-lighting and full-color displays owing to the unique advantage of size-tunable emission color, high photoluminescence quantum yield (PLQY) and toxic-metal-free composition. However, the application of CQD-based electroluminescent white LEDs (WLEDs) is limited by insufficient brightness and spectral tunability due to the simultaneous requirement for a high radiative recombination rate and full-visible-spectrum emission. Herein, we report the synthesis of yellow-emissive CQDs (Y-CQDs) via a one-step solvothermal method using cyanuric chloride and 1-pyrenamine as precursors. The Y-CQDs exhibit bright yellow emission at 525 nm with a broad full-width at half-maximum of 81 nm and an absolute photoluminescence quantum yield of up to 87%. Using Y-CQDs as the active emission material, solution-processed electroluminescent WLEDs were fabricated with different doping concentrations from 1 wt% to 5 wt% in a host–guest system, exhibiting voltage-independent and stable white emissions with a maximum luminance of 18 360–24 092 cd m⁻², corresponding to Commission Internationale de L’Eclairage coordinates and correlated color temperatures of (0.29, 0.31)/6851 K, (0.28, 0.39)/7404 K, and (0.27, 0.38)/7979 K, which exceed those of previously reported CQD-based WLEDs. This study offers a promising way to develop high-brightness electroluminescent WLEDs based on CQD emitters for solid-state lighting applications.