Suppression of temperature quenching in perovskite nanocrystals for efficient and thermally stable light-emitting diodes

Fluoride-treated CsPbBr3 nanocrystals emit light with near unity efficiency at temperatures of up to 373 K. The thermal quenching of light emission is a critical bottleneck that hampers the real-world application of lead halide perovskite nanocrystals in both electroluminescent and down-conversion light-emitting diodes. Here, we report CsPbBr3 perovskite nanocrystals with a temperature-independent emission efficiency of near unity and constant decay kinetics up to a temperature of 373 K. This unprecedented regime is obtained by a fluoride post-synthesis treatment that produces fluorine-rich surfaces with a wider energy gap than the inner nanocrystal core, yielding suppressed carrier trapping, improved thermal stability and efficient charge injection. Light-emitting diodes incorporating these fluoride-treated perovskite nanocrystals show a low turn-on voltage and spectrally pure green electroluminescence with an external quantum efficiency as high as 19.3% at 350 cd m(-2). Importantly, nearly 80% of the room-temperature external quantum efficiency is preserved at 343 K, in contrast to the dramatic drop commonly observed for standard CsPbBr3 perovskite nanocrystal light-emitting diodes. These results provide a promising pathway for high-performance, practical light-emitting diodes based on perovskite nanostructures.

Automated summary

Fluoride-treated CsPbBr3 nanocrystals exhibit near unity emission efficiency at temperatures up to 373 K, with constant decay kinetics. The treatment leads to surfaces rich in fluorine with wider energy gaps than the core, suppressing carrier trapping and improving thermal stability. Devices incorporating these nanocrystals show low turn-on voltage and high external quantum efficiency, with nearly 80% efficiency maintained at high temperatures, offering a promising pathway for high-performance light-emitting diodes based on perovskite nanostructures.