All-Solution-Processed Perovskite Light-Emitting Diodes Based on a Thiol-Modified ZnO Electron-Transporting Layer

All-solution-processed perovskite light-emitting diodes(LEDs)have the potential to be inexpensive and easily manufactured on alarge scale without requiring vacuum thermal deposition of the emissiveand charge transport layers. Zinc oxide (ZnO), which possesses superioroptical and electronic properties, is commonly used in all-solution-processedoptoelectronic devices. However, the polar solvent of ZnO inks cancorrode the perovskite layer and cause severe photoluminescence quenching.In this work, we report the successful dispersion of ZnO nanoparticlesin nonpolar n-octane by controlling the surface ligandsfrom acetates to thiols. The nonpolar ink prevents the destructionof perovskite films. In addition, thiol ligands upshift the conductionband energy level, which also helps inhibit exciton quenching. Consequently,we demonstrate the fabrication of high-performance all-solution-processedgreen perovskite LEDs with a brightness of 21 000 cd/m(2) and an external quantum efficiency of 6.36%. Our work providesa ZnO ink for fabricating efficient all-solution-processed perovskiteLEDs.

Automated summary

In this research, the dispersion of ZnO nanoparticles in nonpolar n-octane was achieved by changing the surface ligands from acetates to thiols. This prevented the destruction of perovskite films and inhibited exciton quenching, leading to the successful fabrication of high-performance all-solution-processed green perovskite LEDs. The brightness of the LEDs reached 21,000 cd/m2 and the external quantum efficiency was 6.36%.