Tetraoctylammonium Bromide Interlayer between NiLiO and Perovskite for Light-Emitting Diodes.

Physical vapor deposition is a favorable technique for fabricating light-emitting diodes (LEDs) due to its scalability and reproducibility. However, the performances of LEDs fabricated via this method are worse than those prepared via solution processing owing to the generation of high defect densities. In this study, we introduce a layer of tetraoctylammonium bromide (TOABr), an interfacial-modification compound containing four long octyl chains that are symmetrically arranged around an N atom, to reduce nonradiative recombination and trap densities in CsPbBr.