Synthesis of self-assembled one-dimensional perovskite nanobelt passivated by homophthalic acid and application in WLED

While there has been extensive investigation of synthesizing perovskite nanocrystals (NCs) in light emitting diode (LED) with high photoluminescence performance and stability, they are still limited by chemical and phase instabilities. Moreover, the protonation occurring between oleic acid (OA) and oleyl amine (OAm), which are common capping ligands to passivate the NCs, promotes the degradation of photoluminescence properties. To overcome these issues, we report a post synthesis passivation strategy for self-assemble CsPbBrI2 1D nanobelt by using bidentate ligand, namely homophthalic acid. The introduced homophthalic acid can passivate the CsPbBrI2 surface defects by reducing exposing Pb2+ to prevent nonradiative recombination. Benefiting from homophthalic acid, the passivated NCs exhibit narrow red photoluminescence at 640 nm with 74 % quantum yield (QY) and remain phase stable after 4 months. The external quantum efficiency (EQE) of the white light emitting diode (WLED) fabricated with QDs passivated with homophthalic acid is 1.99 %, its CIE chromaticity coordinate is (0.31,0.33) and the power efficiency is 2.13 lm/W. •CsPbBrI2 nanocrystals passivated with homophthalic acid exhibit narrow red photoluminescence at 640 nm with excellent quantum yield of 74 %.