Efficient and Stable Perovksite Nanocrystal Light-Emitting Diodes with Sulfobetaine-Based Ligand Treatment

Abstract

Perovskite nanocrystals (PNCs) have got a great attention as a material for optical devices like light-emitting diodes (LEDs) due to excellent properties. However, having the highly dynamic nature of surface ligands, as-synthesized PNCs showed the severe loss of its optical properties, reducing the photoluminescence quantum yield (PLQY). To overcome the optical losses, lots of efforts have been conducted such as surface ligand exchanges. In this study, we treated CsPbBr3 PNCs with 3-(Dodecyldimethyl ammonio)propane-1-sulfonate (12-SBE) ligands and successfully stabilized the PNCs under ambient air and heat. Under optimum ligand exchange conditions, 12-SBE PNCs showed near 100% photoluminescence quantum yield (PLQY) without an increase in the size of the PNCs. After 12-SBE treatment, the agglomeration of PNCs in solution due to ligand loss was suppressed and PNC size growth induced by moisture and oxygen under heating was reduced. Finally, we fabricated 12-SBE PNC LEDs exhibiting 6.7% external quantum efficiency (EQE).