Enhanced Optical and Electrical Properties of Polymer-Assisted All-Inorganic Perovskites for Light-Emitting Diodes

Highly bright light-emitting diodes~based on solution-processed all-inorganic perovskite thin film are demonstrated. The cesium lead bromide (CsPbBr$_{\mathrm{3}})$ created using a new poly(ethylene oxide)-additive spin-coating method exhibits photoluminescence quantum yield up to 60{\%} and excellent uniformity of electrical current distribution. Using the smooth CsPbBr$_{\mathrm{3}}$~films as emitting layers, green perovskite-based light-emitting diodes (PeLEDs) exhibit electroluminescent brightness and efficiency above 53 000 cd m$^{\mathrm{-2}}$~and 4{\%}: a new benchmark of device performance for all-inorganic PeLEDs.