Efficient all-inorganic perovskite light-emitting diodes enabled by manipulating the crystal orientation

Abstract

Metal halide perovskite light-emitting diodes (PeLEDs) are promising for lighting and display application, and the corresponding device performance is highly dependent on the film quality of the active layer. However, it is still very challenging to prepare high-quality all-inorganic perovskite films by solution methods, possibly due to the fast and uncontrollable crystallization process. Herein, we show that we could manipulate crystal orientation along the (110) plane through low-temperature annealing (35–40 °C). The orderly packed crystals contributed to increasing the surface coverage and reducing defect states. As a result, the corresponding well-oriented CsPbBr₃ PeLEDs delivered a champion external quantum efficiency of 16.45%, high brightness of 79 932 cd m⁻², and a decent operation lifetime of 136 h at an initial luminance of 100 cd m⁻². As far as we know, our device performance is among the highest ones for all-inorganic PeLEDs. This work brings new insights into the manipulation of crystal orientation for fabricating high-performance and stable PeLEDs.