Improved photoluminescence stability and defect passivation in SbBr3 post‐treated CsPbBr3 quantum dots under ambient conditions

Abstract Inorganic cesium lead halide perovskites have evoked wide popularity because of their excellent optoelectronic properties, high photoluminescence (PL) quantum yield (PLQY), and narrowband emission. Here, cesium lead bromide (CsPbBr 3 ) quantum dots (QDs) were synthesized via the ligand‐assisted re‐precipitation method. Post‐synthesis treatment of CsPbBr 3 QDs using antimony tribromide improved the PL stability and optoelectronic properties of the QDs. In addition, the PLQY of the post‐treated sample was enhanced to 91% via post‐treatment, and the luminescence observed was maintained for 8 days. The post‐synthesis treatment ensured defect passivation and improved the stability of CsPbBr 3 perovskite QDs. High‐resolution transmission electron microscopy revealed the presence of more ordered, uniform‐sized CsPbBr 3 QDs after post‐synthesis treatment, and the uniformity of the sample improved as the day passed. The formation of a mixed crystal phase was observed from X‐ray diffraction in both as‐synthesized, as well as post‐treated QDs samples with the possibility of a polycrystalline nature in the post‐treated CsPbBr 3 QDs as per the selected area electron diffraction pattern. The X‐ray photoelectron spectroscopy spectra confirmed the presence of antimony and the possibility of defect passivation in the post‐treated samples. These QDs can act as potential candidates in various optoelectronic applications such as photodetectors and light‐emitting diodes due to their high PLQY and longer lifetime.