Efficient Perovskite-Based Red Micro Light-Emitting Diodes

Micro light-emitting diodes (LEDs) have unique advantages in displays, such as high resolution, high brightness, and fast response time, making them suitable for applications in augmented reality and virtual reality. However, red micro LEDs suffer from serious size-dependent efficiency droop, which limits their use in full color displays. Perovskite LEDs have been explored to obtain red micro LEDs, but reported external quantum efficiencies (EQEs) have been below 1% due to the lack of uniform and efficient perovskite films. Here we demonstrate a high-quality perovskite film that enables efficient red micro LEDs with an EQE of 8.6%, even at a small pixel diameter of $20~\mu \text{m}$ . To achieve this, we incorporate zinc acetate into the perovskite precursor solution, which promotes the formation of the $\gamma $ -CsPb( $\text{I}_{{1}-{x}}$ Br $_{x}{)}_{{3}}$ perovskite and inhibits the growth of large grains by bonding to the surface of the perovskite grains. These findings demonstrate the great potential of perovskite-based red micro LEDs for future display technologies.