Bottom-up synthesized carbon nitride quantum dot-based light-emitting diodes

Abstract

Carbon nitride quantum dots (CNQDs) represent an emerging class of polymeric semiconductor nanomaterials that combines environmental friendliness with facile synthesis, solution-processability and tunable optoelectronic properties. Despite these advantages, their application in optoelectronic devices remains largely unexplored. Here we demonstrate high-performance light-emitting diodes (LEDs) employing thermally polymerized CNQDs as the emissive layer. The synthesized CNQDs exhibit uniform size distribution, long-term colloidal stability, and a remarkable photoluminescence quantum yield. Detailed charge transport analysis reveals matched electron–hole mobility of CNQDs, enabling efficient radiative recombination. The optimized CNQD-LED architecture achieves breakthrough performance metrics: a low turn-on voltage of 2.8 V, a maximum luminance of 885 cd m⁻², and a record external quantum efficiency of 2.14%. This study not only establishes CNQDs as viable alternatives to conventional heavy-metal QDs but also provides a general framework for developing sustainable optoelectronic materials, paving the way for environmentally benign display technologies.