Understanding and Eliminating Transient Photoluminescence Quenching in Lead Halide Perovskite Quantum Dots for Photonic Applications

Perovskite quantum dots (QDs) hold great promise for photonic applications, including solar cells, light-emitting diodes, lasers, and photodetectors. However, their optical properties are highly sensitive to environmental conditions, owing to their large surface-to-volume ratio, particularly under light illumination, which can result in reduced performance in QD-based devices. Therefore, understanding the mechanisms and mitigating light-induced degradation are crucial for QD-based photonic devices. Under continuous light exposure in an ambient atmosphere, we observed transient photoluminescence (PL) quenching in lead halide perovskite QDs, with the PL dropping by more than 50% on the minute time scale. This quenching was reversible upon blocking the light. We saw that trap states and defects on QD surfaces are responsible for this transient PL quenching as they capture photoexcited electrons or holes, resulting in charged QDs. The charging effect facilitates nonradiative Auger recombination, causing temporary PL quenching. To mitigate the charging effect, we passivated the QDs using dodecyldimethylammonium bromide (DDAB). Following surface passivation, the photoluminescence intensity and stability of the QDs were significantly enhanced with the surface charging effects greatly reduced. This work provides insight into QD charging mechanisms and demonstrates a strategy for mitigating them, which is critical for both fundamental understanding and the advancement of QD-based photonic technologies.