Microscale Perovskite Quantum Dot Light‐Emitting Diodes (Micro‐PeLEDs) for Full‐Color Displays

Abstract Group III–V semiconductor‐based microscale light‐emitting diode (micro‐LED) displays are recognized as one of the most promising display technologies with superhigh brightness and resolution, strong contrast, and superlarge color gamut but currently suffer from low efficiency, low production yield, and high cost. Here, it is proposed to realize cost‐effective and full‐color micro‐LED displays by using microscale perovskite quantum dot LEDs (micro‐PeLEDs) as emitters. Bright and uniform red‐, green‐, and blue‐emitting (RGB) micro‐PeLED arrays with each pixel size as small as 45 µm are fabricated by in situ inkjet printing a perovskite quantum dot (PeQD) emissive layer in the structure of indium tin oxide/poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS)/poly(9‐vinylcarbazole) (PVK)/sodium dodecyl sulfate (SDS)/PeQD/1,3,5‐tris(1‐phenyl‐1 H ‐benzimidazol‐2‐yl)benzene (TPBi)/LiF/Al. These RGB micro‐PeLED arrays display an external quantum efficiency of 0.832%, 0.419%, and 0.052% for red, green, and blue colors, a resolution of 210 PPI, and a wide color gamut (135% of the National Television Standards Committee standard). The authors further demonstrate flexible and full‐color active‐matrix micro‐PeLED displays, which have potential applications in future ultrahigh‐definition displays, light communication, and artificial intelligence.