In-situ guanidinium bromide passivation treatment of CsPbBr3 perovskite quantum dots exhibiting high photoluminescence and environmental stability

Abstract

All-inorganic CsPbX3 perovskite quantum dots (QDs) are of great interest in the new-generation optoelectronic applications. However, the inferior long-term stability of CsPbX3 QDs has severely hindered their real applications. In this paper, we have developed a simple and efficient in-situ guanidinium bromide (GABr) passivation approach to synthesize CsPbBr3 QDs by introducing appropriate amount of GABr into the precursor solution using the traditional hot injection method. The in-situ GABr passivation treatment is demonstrated to effectively improve the crystallinity and regulate the grain size of CsPbBr3 QDs without changing the crystal structure. More importantly, the in-situ GABr passivation treatment strategy can induce the passivation of surface defects and formation of the stable bromine-rich surface with tri-ligand mode. Consequently, the in-situ GABr passivated CsPbBr3 QDs display remarkably improved optical properties and environmental stability. Additionally, the in-situ GABr passivated CsPbBr3 QDs have been successfully employed in photodetectors and white light-emitting diodes (WLEDs), showing great practical application prospects. Our work may afford a new guideline to prepare CsPbBr3 QDs with high photoluminescence and environmental Stability.