Fabrication of Highly Luminescent Quasi Two-Dimensional CsPbBr₃ Perovskite Films in High Humidity Air for Light-Emitting Diodes

Perovskite light-emitting diodes (LEDs) have attractedextensiveattention in recent years due to their outstanding performance andpromise in lighting and display applications. However, the fabricationof perovskite LEDs usually requires a low-humidity atmosphere, whichis unfavorable for industrial production. Herein, we report an effectivestrategy to fabricate highly luminescent quasi two-dimensional CsPbBr3 perovskite films in an ambient atmosphere with a humidityup to 60%. We reveal that the hole transport layer (HTL) plays a significantrole in the morphology and optical properties of the perovskite films.Using hydrophobic self-assembled monolayer materials as HTLs can remarkablyimprove the quality of the perovskite films processed in high humidityair. The resultant perovskite LEDs show reduced leakage current andsignificantly enhanced performance. Furthermore, surface treatmentis conducted to prevent water invasion and promote radiative recombinationin perovskite films and LEDs. Eventually, the perovskite LEDs exhibitbright green emission with an external quantum efficiency of 4.87%.The present work provides a feasible pathway to overcome the humiditylimitation for obtaining bright perovskite films and LEDs, which wouldcontribute to further reducing the fabrication cost of perovskiteLEDs and promoting their applications.