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Recent studies of sky‐blue perovskite light‐emitting diodes (PeLEDs) have extensively promoted optimal device design to achieve an external quantum efficiency (EQE) above 12%. However, the development of thin‐film deep‐blue PeLEDs lags dramatically behind, especially with regards to meeting the latest Rec. 2020 standard. A trichloro(3,3,3‐trifluoropropyl) silane post‐treatment that drives the emission of perovskite into the deep‐blue region, ranging from 440 to 460 nm, which meets the Rec. 2020 standard, is proposed. The chlorine ions released from the organotrichlorosilane molecules during their polycondensation reaction provide an addition halide source to fine tune the composition of the mixed halide perovskite films, leading to increase of bandgap and deep‐blue emission. In addition, hydrogen bonds between the hydroxy groups of silane molecules and halide anions in perovskite can suppress ion migration for improving emission stability. As a result, an optimal PeLED is developed with deep‐blue emission at 458 nm and excellent color stability, which yields an EQE and luminance of 1.1% and 130 cd m−2, respectively, representing a state‐of‐the‐art result for thin‐film PeLEDs in this emission region. This work paves the way to achieve high‐performance deep‐blue PeLEDs with stable emissions to meet the demand for potential applications such as full‐color display.

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In recent years, metal halide perovskites have received extensive attention due to their superior optoelectronic properties and solution processability, which also become a research hotspot in the field of optoelectronics. Among all the perovskite optoelectronics applications, perovskite light-emitting diode (LED) becomes one of the important research topics because it is likely to be used in the next-generation display technique. Based on the high photoluminescence quantum yield (PLQY), facilely tunable bandgaps, and sharp emission of perovskite material, the external quantum efficiency of perovskite LED has increased from less than 1% to over 20% within only five years, showing the most rapid development speed in the LED field. During the 5-year exploration of perovskite LEDs, researchers have focused their efforts on how to realize the crystal-growth control in the perovskite film formation process, enhance PLQY of the perovskite films, and improve the performance of perovskite LEDs. Among all the approaches, the utilization of organic additives including small molecules and polymers proves to be an effective strategy. Here, in this article, we review the recent advances in metal halide perovskite LEDs based on the strategy of organic-additive treatment. We also analyze and discuss the interaction between organic additive and perovskite crystal as well as its influence on the performance of perovskite LED. In the end, we discuss the challenges remaining in perovskite LEDs and the prospects for perovskite LEDs.