Efficient Thermally Evaporated Perovskite Light-Emitting Devices via a Bilateral Interface Engineering Strategy

Physical vapor deposition has emerged as a promising strategy for efficient and stable all-inorganic perovskite light-emitting devices (PeLEDs). However, the thermally evaporated PeLEDs still suffer from unsatisfactory optoelectrical performance because of the massive nonradiative defects. Herein, we demonstrate an efficient bilateral interfacial defect-passivation strategy toward high-performance PeLEDs with a thermally deposited CsPbBr3 emissive layer (EML). Specifically, the nonradiative defects from the bulk as well as the EML/charge transport layer (CTL) interface are significantly suppressed by implementing the 3-amino-1-propanol (3AP)-modified PEDOT:PSS and introducing ammonium salts, respectively. Simultaneously, both the 3AP induced less-conductive Cs4PbBr6 and ammonium salts can balance the charge injection into the EML effectively. As a result, we achieved efficient PeLEDs based on thermally evaporated CsPbBr3 with a luminance of 15745 cd/m2, current efficiency of 32 cd/A, external quantum efficiency of 8.86%, and lifetime of 3.74 h. The strategy proposed here may shed light on the development of highly efficient thermally evaporated PeLEDs.