Efficient Blue Perovskite LEDs via Bottom‐Up Charge Manipulation for Solution‐Processed Active‐Matrix Displays

Abstract Perovskite light‐emitting diodes (PeLEDs) are emerging as strong candidates for next‐generation displays due to their outstanding optoelectronic properties, solution processability, and cost‐effectiveness. However, the development of highly efficient blue PeLEDs remains a significant challenge. Here, a bottom‐up strategy is introduced for precise charge manipulation in blue perovskites to enhance radiative recombination efficiency. By employing 1,3‐bis(N‐carbazolyl)benzene as an inserted hole transport layer, improved hole injection efficiency is achieved while effectively suppressing reverse electron transport and exciton quenching. Additionally, a fluorinated ester additive is incorporated to control perovskite crystallization, facilitating the formation of well‐aligned reduced‐dimensional phases to reduce nonradiative recombination losses. The resulting blue PeLEDs exhibit a record‐breaking external quantum efficiency of 25.87%, the highest reported for one‐step‐prepared blue perovskite films. Furthermore, integration with thin‐film transistor circuits enables solution‐processed active‐matrix perovskite displays with sharp and uniform patterning. This work provides a comprehensive pathway for advancing blue PeLEDs toward high‐performance display applications.