Pixelated quantum-dot superlattice LEDs.

Quantum dot (QD) superlattices offer collective optoelectronic properties distinct from disordered solids1-4, but their integration into high-resolution display devices remains elusive because of difficulties in achieving spatially defined, structurally coherent thin films. Here we report a scalable strategy for fabricating pixelated perovskite QD (PeQD) superlattice thin-film arrays that feature in-plane long-range order, vertical confinement and precise spatial patterning. By engineering rhombic dodecahedral CsPbBr3 nanocrystals with robust surface termination by a ligand-fluoride co-stabilization approach, we direct the formation of hexagonally close-packed superlattice films using capillary liquid-bridge confined assembly. These superlattice films exhibit reduced energetic disorder and enhanced electronic coupling. When integrated into light-emitting diodes (LEDs), the electrically driven PeQD superlattices yield an external quantum efficiency of 30.9%, high luminance of 117,144 cd m-2 and pixel densities of up to 5,080 pixels per inch. The devices show an extrapolated operational half-lifetime (T50) of 12,411 h at 100 cd m-2-more than 1,000-fold longer than previously reported pixelated PeQD LEDs. Moreover, we demonstrate the direct integration of patterned superlattices onto a commercial thin-film transistor backplane to construct a 1.85-inch active-matrix display with full greyscale control and video playback ability. These results establish colloidal QD superlattices as a viable material platform for next-generation high-resolution, stable and efficient perovskite displays.