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In recent years, perovskite light-emitting diodes (PeLEDs) have developed rapidly with the highest external quantum efficiency exceeding 20%. Their unbalanced carrier injection and non-radiative recombination assisted by defects lead to the destruction of perovskite crystal structures and poor device stability, which hinders their commercialization process. Thus, to understand the origin of device performance, the key is to figure out the charge-carrier dynamics of the devices. In this review, the charge-carrier dynamics of perovskites are discussed, including radiative and non-radiative recombination, together with the various passivation strategies. Second, we focus on the interfacial carrier dynamics and its influence on device performance. Various strategies to improve the injection balance have been implemented to address the inherent challenges associated with PeLEDs. Last but not least, the characterization techniques of PeLEDs are provided to study the carrier dynamics of PeLEDs. [ABSTRACT FROM AUTHOR]

Halide perovskites have been one of the most promising research hotspots in the optoelectronic field. Recently, the issue of ion migration has been proved to be of great significance to their long-term stability and performance of optoelectronic devices. However, the stability of perovskite Cs2SnX6 (X = I, Br, Cl) under the light or electric field conditions has not been explored. In this work, we reported halide ion migration in lead-free all‐inorganic perovskite Cs2SnX6. The calculated formation energy to some degree reveals the concentration of the halide vacancy, which provides the favorable conditions for halide ion migration. Importantly, the theoretical long-term ion migration barriers are investigated to be higher than 1.00 eV, indicating they are relatively stable compared to CsPbX3, and the computational result matches the experimental result with the Nernst−Einstein relation that we adopted. The halogen ion migration energy barrier is 0.91 eV under the bias of 5 V, indicating that the perovskite Cs2SnX6 is relatively stable under a certain electric field. Furthermore, the experimental comparison of XRD results demonstrate that perovskite Cs2SnX6 has no obvious ion migration under certain light conditions. Finally, the analysis results show the Sn–X bond strength that explains the cause of such high barriers. These results reveal the migration mechanism of halide ions and provide new impetus for their optoelectronic applications. [ABSTRACT FROM AUTHOR]