All Solution‐Processed High Performance Pure‐Blue Perovskite Quantum‐Dot Light‐Emitting Diodes

Abstract Solution‐processed light‐emitting diodes (LEDs) show great potential for low‐cost fabrication of large‐area display panels, but the efficient perovskite LEDs (PeLEDs) cannot be achieved by all solution process, because the perovskite emitter is easily destroyed by subsequent solution. In particular, the solution‐processed PeLEDs with blue emission wavelength in 460–470 nm (pure‐blue, meeting Rec. 2020 standards) still is inferior. Here, highly efficient and stable pure‐blue PeLEDs are achieved by all solution process based on colloidal perovskite quantum dots and difunctional ZnO (D‐ZnO) nanocrystals. The D‐ZnO nanocrystals are obtained by a ligand strategy of phenethylammonium bromide, which not only repairs the perovskite surface destroyed by the solvent of the D‐ZnO solution, but also enables the balanced charge injection to suppress Auger recombination. The PeLED presented pure‐blue emitting at 470 nm wavelength, a maximum luminance of 11 100 cd m ‐2 , and external quantum efficiency of 8.7% (record efficiency for pure‐blue emission). The device also showed a continuous operation half‐lifetime of 35 h at luminance of 100 cd m ‐2 .