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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]

Current–voltage hysteresis of perovskite solar cells (PSCs) has raised the concern of accurate performance measurement in practice. Although various theories have been proposed to elucidate this phenomenon, the origin of hysteresis is still an open question. Herein, the use of guanidinium cation (Gu+)‐dopant is demonstrated to tailor the crystal structure of mixed‐cation formamidinium‐cesium lead triiodide (FA0.83Cs0.17PbI3) perovskite, resulting in an improved energy conversion efficiency and tunable current–voltage hysteresis characteristic in planar solar cells. Particularly, when the concentration of Gu‐dopant for the perovskite film increases, the normal hysteresis initially observed in the pristine PSC is first suppressed with 2%‐Gu‐dopant, then changed to inverted hysteresis with a higher Gu‐dopant. The hysteresis tunability behavior is attributed to the interplay of charge/ion accumulation and recombination at interfaces in the PSC. Furthermore, compared to the cell without Gu+‐dopant, the optimal content of 2% Gu+‐dopant also increases the device efficiency by 14%, reaching over 17% under one sun illumination. A new method to control current–voltage hysteresis of planar structured FA0.83Cs0.17PbI3 perovskite solar cells (PSCs) is presented while enhancing device efficiency through tailoring the crystal structure of the perovskite compound with a guanidinium cation (Gu+)‐dopant. New insights into the correlation of the dynamics of device hysteresis with the interfacial charge recombination and accumulation in the PSCs are revealed. [ABSTRACT FROM AUTHOR]