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

Abstract

Perovskite nanocrystals (PNCs) possess outstanding optical properties such as narrow full-width at half-maximum (fwhm) emission and color tunability. However, the labile ionic nature and weakly bound surface ligands of PNCs result in colloidal instability and crystal structure deformation, thus degrading their optical properties. In this study, we treated CsPbBr3 PNCs with 3-(dodecyldimethylammonio)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). Moreover, the PL lifetime of 12-SBE PNC LEDs was enhanced 2-fold compared to oleylamine (OAM) PNC LEDs.