Efficient and Stable Pure Green All-Inorganic Perovskite CsPbBr3 Light-Emitting Diodes with a Solution-Processed NiOx Interlayer

The perovskite-based optoelectronic applications always suffer from stability issues, due to the intrinsic chemical instability of the perovskite materials. Besides, poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) is always utilized as an anode buffer layer in thin-film perovskite light-emitting diodes (PeLEDs), which may lead to stability issues due to the hygroscopic and acidic nature of PEDOT:PSS. In this paper, inorganic metal oxide NiOx is employed as a hole injection layer (HIL) and hole transport layer (HTL) to substitute detrimental PEDOT:PSS in all-inorganic PeLEDs. Then fully covered CsPbBr3 polycrystalline films are fabricated by using a one-step spin-coating method based on nonstoichiometric and polymer-assisted perovskite precursor solutions. The optimized films not only have compact morphology but also have excellent photoluminescence quantum yield (PLQY). Encouragingly, by introducing a metal oxide NiOx, the CsPbBr3 PeLEDs show a maximum luminance of 23 828 cd m–2 and maxi...