Multidentate ligand passivation enabled enhanced photoluminescence and stability of CsPbBr₃ nanocrystals for white light-emitting diodes

Inorganic cesium lead halide perovskite nanocrystals (NCs) show promising application in the field of optoelectronic devices. However, the poor stability and low photoluminescence quantum yield (PLQY) have been a huge hurdle for practical applications. Ligand engineering strategy was proven to be an effective way to improve the stability and PLQY. Herein, we utilize a multidentate ligand of Boc-D-Glutamic acid (BDGA) to treat the perovskite NCs, enabling exceptional quantum yield approaching 100% and superior colloidal stability (about 10% reduction after 60 days storage at ambient conditions), as well as greatly enhanced resistance to thermal treatment and UV irradiation which can be ascribed to the surface defect passivation and an efficient ligand exchange with robust affinity and/or compensation. Besides, the as-fabricated white light-emitting diodes (WLEDs) exhibits a high luminous efficiency of 93.5 lm/W and a wide color gamut (128% of the National Television System Committee and 95% Rec. 2020). This work provides a facile route to realize high PLYQ and improve the challenging stability issue in perovskite NCs.