Universal Molecular Control Strategy for Scalable Fabrication of Perovskite Light-Emitting Diodes

Despite the rapid progress in perovskite light-emitting diodes (PeLEDs), the electroluminescence performance of large-area perovskite devices lags far behind that of laboratory-size ones. Here, we report a 3.5 cm x 3.5 cm large-area PeLED with a record-high external quantum efficiency of 12.1% by creating an amphipathic molecular interface modifier of betaine citrate (BC) between the perovskite layer and the underlying hole transport layer (HTL). It is found that the surface wettability for various HTLs can be efficiently improved as a result of the coexistence of methyl and carboxyl groups in the BC molecules that makes favorable groups to selectively contact with the HTL surface and increases the surface free energy, which greatly facilitates the scalable process of solution-processed perovskite films. Moreover, the luminous performance of perovskite emitters is simultaneously enhanced through the coordination between C=O in the carboxyl groups and Pb dangling bonds.

Automated summary

The external quantum efficiency of large-area PeLEDs was significantly increased to 12.1% by introducing amphipathic molecular interface modifier betaine citrate (BC), which also improved the scalability of solution-processed perovskite films. Additionally, the coordination between C=O in the carboxyl groups and Pb dangling bonds enhanced the luminous performance of perovskite emitters.