Efficient CsPbBr3 sky-blue perovskite light-emitting devices Co-regulated by dual polymer additives

Metal halide perovskite has aroused broad interests in fabricating colorful electroluminescent devices towards solid-state lighting and display technologies. However, blue perovskite light-emitting devices (PeLEDs) still face thorny problems such as poor working stability, low efficiency, and spectral instability. Here, we exploit a synergistic regulation on the crystallization and growth of pure bromide perovskite through interface inducing and polymer spatial confinement strategy to achieve blue emission. It is found that the ethanolamine modified PEDOT:PSS could induce low-dimensional Cs4PbBr6:CsPbBr3 composite. Polyvinyl pyrrolidone (PVP) together with poly ethylene glycol (PEG) additives inhibited its coalescence and ripening and passivated the defects simultaneously. As a consequence, dual-polymer regulated Cs4PbBr6:CsPbBr3 PeLEDs presented an external quantum efficiency (EQE) of 3.73% and maximum brightness of 7051 cd/m2. Our facile method may provide alternative approaches to construct efficient blue PeLEDs.