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

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.