Enhancing the quantum yield and stability of CsPbBr3 quantum dots with zwitterionic ligand post-treatment

Abstract

The poor stability and low photoluminescence quantum yield (PLQY) of halide perovskite quantum dots (QDs) have been major challenges for their future practical application. Ligand engineering has been demonstrated as an effective approach for enhancing both stability and PLQY. Herein, we introduce a zwitterionic ligand, specifically N-tetradecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (TDPS), to synthesize stable CsPbBr3 QDs by ligand post-treatment. The as-prepared TDPS-QDs exhibited an exceptional PLQY of 86.5 % and superior colloidal stability when exposed to UV light, heat, and polar solvents, owing to surface defect passivation and strong affinity to the surfaces. The PL intensity of TDPS-QDs maintains approximately 68 % (120 min) and 103 % (48 h) of its initial emission intensity under continuous irradiation or heat, respectively, whereas OA-QDs (pristine CsPbBr3 QDs) undergo greater quenching within a shorter period. The findings highlight the potential for TDPS ligand modification to simultaneously improve the QY and stability, thus opening novel avenues for future applications involving CsPbBr3 QDs.