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

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).

Automated summary

This study demonstrates highly efficient and stable pure-blue perovskite light-emitting diodes (PeLEDs) achieved through an all-solution process. By using difunctional zinc oxide (D-ZnO) nanocrystals, the damaged perovskite surface is repaired and balanced charge injection is achieved to improve the luminous efficiency. The fabricated PeLEDs showed pure-blue emission at a wavelength of 470 nm, with high luminance and external quantum efficiency, as well as a long continuous operation time.