Efficient Inorganic Perovskite Light-Emitting Diodes with Polyethylene\nGlycol Passivated Ultrathin CsPbBr₃ Films

Abstract

Efficient\ninorganic perovskite light-emitting diodes (PeLEDs) with an ultrathin\nperovskite emission layer (∼30 nm) were realized by doping\nLewis base polyethylene glycol (PEG) into CsPbBr₃ films.\nPEG in the perovskite films not only physically fills the crystal\nboundaries but also interacts with the perovskite crystals to passivate\nthe crystal grains, reduce nonradiative recombination, and ensure\nefficient luminance and high efficiency. As a result, promoted brightness,\ncurrent efficiency (CE), and external quantum efficiency (EQE) were\nachieved. The nonradiative decay rate of the PEG:CsPbBr₃ composite film is 1 order of magnitude less than that of the neat\nCsPbBr₃ film. After further optimization of the molar ratio\nbetween CsBr and PbBr₂, a peak CE of 19 cd/A, a maximum\nEQE of 5.34%, and a maximum brightness of 36600 cd/m² were\nachieved, demonstrating the interaction between PEG and the precursors.\nThe results are expected to offer some helpful implications in optimizing\nthe polymer-assisted PeLEDs with ultrathin emission layers, which\nmight have potential application in see-through displays.