Ligand-modified CsPbBr3 with high quantum yield for green light-emitting diodes

Abstract Perovskite quantum dots (PQDs) hold immense potential for application in the subsequent LEDs because of their exceptional optoelectronic properties. Nevertheless, the presence of surface defects in PQDs leads to instability and leaves room for improvement. Therefore, this paper reports a ligand modification method that stabilizes CsPbBr3 PQDs, with vinylphosphonic acid (VPA) serving as a functional ligand to regulate the nucleation and growth of PQDs during synthesis. PLQY reached as high as 81.8%. VPA also repairs surface defects on PQDs and enhances charge transport. The device brightness efficiency reached 13, 152 cd/m². This strategy for ligand exchange maintained the dimensions and shape of CsPbBr3 PQDs, while also improving the optical characteristics and electrical conductivity of CsPbBr3 PQDs films. This work opens up a new pathway for achieving stable, high-performance LEDs using PQDs.