Fluorine-modified passivator for efficient vacuum-deposited pure-red perovskite light-emitting diodes

Vacuum-deposited perovskite light-emitting diodes (PeLEDs) have demonstrated significant potential for high-color-gamut active-matrix displays. Despite the rapid advance of green PeLEDs, red ones remain a considerable challenge because of the inferior photophysical properties of vacuum-deposited red-light-emitting materials. Here, a rationally designed fluorine-modified phosphine oxide additive was introduced to in-situ passivate vacuum-deposited perovskites. The highly polar 2-F-TPPO incorporated perovskite films demonstrated enhanced photoluminescence quantum yield (PLQY), suppressed defects, and improved crystallinity. When implemented as active layers in PeLEDs, an external quantum efficiency (EQE) of 12.6% with an emission wavelength of 640 nm is achieved, which was 6 times higher compared to the previously reported most efficient vacuum-deposited red PeLEDs (EQE below 2%). Our findings lay the foundations for the further exploration of high-performance vacuum-deposited PeLEDs toward full-color perovskite displays.