Continuous wave laser fabrication of small pitch/size perovskite pixels realizes high-resolution color conversion micro-LED displays†

As a new generation of display technology, micro-light-emitting diodes (micro-LEDs) have been widely recognized owing to their excellent performance in brightness, contrast ratio, resolution, etc. This work proposes a continuous wave (CW) laser writing strategy to achieve perovskite quantum dots (PQDs) array with small pixel size and pitch, overcoming the processing difficulties and limitations of mass transfer. Since PQDs have highly dynamic surface ligand states and low ionic bond energy, suitable laser power can quench PQDs and form an array area. The use of low-power CW lasers in the laser direct writing process, on the one hand, greatly maintains the luminescence performance and edge flatness of each PQD array, and the pixel pitch (1.5 μm–9 μm)/size can be adjusted arbitrarily, which meets the high-resolution micro-display requirements. On the other hand, we found that after the low-power laser quenches the PQDs, its residual oxide can absorb photons, thus reducing the backlight leakage in color conversion micro-LEDs. Finally, red/green/blue three-color conversion micro-LED and laser projection displays were realized; these results provide a feasible strategy for next-generation micro-LED displays.