One‐Step, Mask‐Free, Rapid Laser Writing Fabrication of Electroluminescent Perovskite@Oxide Pixels for Ultra‐High PPI, Efficient Micro‐QLEDs

Abstract Wide color gamut and high resolution are becoming key features of the new generation of displays, and hence quantum dots pixels with high luminescence purity have been placed great expectations. However, how to facilely and rapidly fabricate electroluminescent pixels with both high pixels per inch (PPI) and high quantum efficiency has been a great challenge. Here, a one‐step, mask‐free, rapid laser writing strategy to fabricate ultra‐high resolution perovskite quantum dots (PQDs) pixels is presented. It is found that the laser‐induced reaction can convert PQDs into oxide, forming perovskite@oxide pixel arrays, replacing the complex etching and deposition processes previously used. Benefiting from the formation of the oxide layer, electrons transport can be effectively blocked in the non‐emitting region, thus reducing the charge leakage in micro quantum dots light emitting diodes (Micro‐QLED) arrays. Finally, red, green, blue Micro‐QLEDs are achieved with PPIs ranging from 2000 to 5000 and the highest external quantum efficiency of 17.24%, 21%, and 6.6% respectively. These results are record‐breaking in perovskite Micro‐QLEDs, providing the strategy for active‐matrix electroluminescent high‐resolution pixel arrays for next‐generation monochromatic displays.