Highly stable and bright CsPbI3 nanocrystal red emitters based on color-conversion from InGaN-based blue light-emitting diodes

Toward the super-smart society, next-generation display technologies with ultra-small size and high resolution are required. MicroLEDs are promising key technologies for next-generation full-color displays, and the external quantum efficiency in the red region should be improved. To improve red emission efficiency, we propose color-conversion red emitters combined with blue InGaN LEDs and lead-halide perovskite nanocrystals (PNCs) by using a coating process. We improved the stability of PNCs under photoexcitation by dispersing them in a methacrylate-based polymer binder, probably because of the suppressed ligand desorption and nonradiative surface recombination process. PNC films were bonded onto a blue InGaN LED to fabricate a color-conversion LED, demonstrating almost complete red conversion with higher optical performance (power density: 3.5 mW/cm2; luminance: 1.9 × 103 cd/m2) at a high current density (270 mW/cm2). This performance was achieved while maintaining the same level of external quantum efficiency (26.2%) and device lifetime (103 h) as those reported for the current PNC red LEDs. Therefore, the color-conversion LED may be a milestone in improving the device performance over the entire visible region and realizing low-cost microLED applications.