High Brightness and Enhanced Stability of CsPbBr3‐Based Perovskite Light‐Emitting Diodes by Morphology and Interface Engineering

A CsPbBr3‐based all‐inorganic perovskite light‐emitting diode (PeLED) with ultrahigh brightness and enhanced stability is prepared by controlling of morphology and interface engineering. A nonionic surfactant polyoxyethylene (20) sorbitan monolaurate is introduced into the CsPbBr3 film, which induces tightly arranged grains in the perovskite film, thus highly passivating the defects at the grain boundaries, resulting in a performance‐enhanced PeLED with a highest brightness of 111 000 cd m−2, a peak current efficiency (CE) of 21.1 cd A−1, a maximum external quantum efficiency (EQE) of 5.55%, and an operational lifetime of 4.5 h. The device properties are further improved by adding an anionic surfactant sodium dodecyl benzene sulfonate to modify the hole injection layer poly(ethylenedioxythiophene):polystyrenesulfonate. The hole current density is increased, further balancing the charge injection and transport. Finally, the optimal device displays an ultrahigh brightness of 179 000 cd m−2, a peak CE of 28.0 cd A−1, a maximum EQE of 7.39%, and a further prolonged lifetime of 6 h. A CsPbBr3‐based all‐inorganic perovskite light‐emitting diode (PeLED) is prepared by controlling of morphology and interface engineering. The optimal device displays an ultrahigh brightness of 179 000 cd m−2, a peak current efficiency of 28.0 cd A−1, a maximum external quantum efficiency of 7.39%, and an operational lifetime of 6 h.