Highly efficient light-emitting diodes via self-assembled InP quantum dots

Heavy-metal-free quantum dot light-emitting diodes (QLEDs) face commercialization challenges due to low efficiency and poor stability. Spin-coated quantum dot films often create charge leakage areas, limiting device performance. Here, we develop an evaporative-driven self-assembly strategy that enables the preparation of uniform and dense InP-based quantum dot films. During device operation, these films effectively suppress performance degradation caused by charge leakage. QLEDs with uniform and dense InP-based quantum dot films achieve high external quantum efficiency (26.6%) and luminance (1.4 × 10⁵cd m^-2), along with considerable stability (extrapolated T₅₀ lifetime of 4026 hours at 1000 cd m^-2). For a 2 × 3 cm² InP-based device, the peak external quantum efficiency reaches 21.1%. By combining high-performance QLEDs with lithography technology, we fabricate miniaturized QLEDs with a minimum pixel size of 3 μm, achieving a resolution as high as 5080 pixels per inch and a peak external quantum efficiency of 22.6%.