Real-Time Blinking Suppression of Perovskite Quantum Dots by Halide Vacancy Filling

Despite the excellent optoelectronic properties of halide perovskites, the ionic and electronic defects adversely affect the stability and durability of perovskites and their devices. These defects, intrinsic or produced by environmental factors such as oxygen, moisture, or light, not only cause chemical reactions that disintegrate the structure and properties of perovskites but also induce undesired photoluminescence blinking to perovskite quantum dots and nanocrystals. Blinking is also caused by the nonradiative Auger processes in the photocharged quantum dots or nanocrystals. Herein, we find real-time suppression of halide vacancy-assisted nonradiative exciton recombination and photoluminescence blinking in MAPbBr(3) and MAPbI(3) perovskite quantum dots by filling the vacancies using halide precursors (MABr and MAI). Also, halide vacancy filling increases the photoluminescence quantum efficiencies and lifetimes of the quantum dots. We estimate the rates of halide vacancy-assisted nonradiative recombination at 1 x 10(8) s(-1) for MAPbBr(3) and 1.9 x 10(9) s(-1) for MAPbI(3) quantum dots. The real-time blinking suppression using the halide precursors and statistical analysis of the ON/OFF blinking time reveal that the halide vacancies contribute to the type-A blinking through charging and discharging. Conversely, the blinking of the quantum dots after halide vacancy filling is dominated by the type-B mechanism.

Automated summary

Despite the excellent optoelectronic properties of halide perovskites, defects such as halide vacancies can adversely affect their stability and durability. By using halide precursors to fill these vacancies, real-time suppression of nonradiative exciton recombination and photoluminescence blinking in perovskite quantum dots is achieved, leading to improved quantum efficiencies and lifetimes. Statistical analysis also reveals different types of blinking mechanisms in quantum dots before and after halide vacancy filling.