Microsecond-response perovskite light-emitting diodes for active-matrix displays

Perovskite light-emitting diodes (PeLEDs) could be of use in the development of active-matrix displays. However, due to ion migration in crystal structure, PeLEDs have electroluminescence rise times over milliseconds, which is problematic for the development of high-refresh-rate displays. Here, we show that the electroluminescence rise time of PeLEDs can be reduced to microseconds using an individual-particle passivation strategy. The approach is based on BF4 - ions that can passivate every nanocrystal in a perovskite emissive layer during film deposition. It leads to a defect-free film with discrete nanostructure and excellent crystallinity, which inhibits ion migration. Our strategy can be applied in perovskite nanocrystal films with different colours: red (635 nm), green (520 nm) and blue (475 nm). These PeLEDs all demonstrate response times within microseconds and high external quantum efficiencies of 22.7%, 26.2% and 18.1%, respectively. This allows us to create microsecond-response active-matrix PeLEDs that exhibit external quantum efficiencies above 20% at a display brightness of 500-3,000 cd m-2 for green devices with a resolution of 30 pixels per inch. We also develop microsecond-response red, green and blue active-matrix displays with 90 pixels per inch. An individual-particle passivation strategy that reduces ion migration in perovskite nanocrystal film can be used to make high-refresh-rate active-matrix displays with microsecond response times reduced by three orders of magnitude compared with typical perovskite light-emitting diodes.