Improving the Efficiency and Stability of Green-Light Perovskite CsPbBr3 LEDs via Low-Temperature Annealing

All-inorganic lead bromide perovskite CsPbBr3 has garnered considerable attention due to its high thermal stability and rapid radiative recombination. Unfortunately, it is still a big challenge to further improve the efficiency and stability of the CsPbBr3 film via the solution processing technique. In this study, we report a method to enhance the CsPbBr3 film quality via annealing at a low temperature of 38 °C. The low-temperature annealing slows the phase transition, allowing for the orderly arrangement of crystal orientations and a surface with fewer defects. With this method, the fabricated CsPbBr3 PeLED exhibits great stability and bright luminescence, achieving an external quantum efficiency (EQE) of 8.21%. The PeLEDs fabricated at 38 °C demonstrated a low turn-on voltage of 1.5 V, with high current densities of 66.8 mA/cm2 at 2.0 V and 371 mA/cm2 at 3.0 V. These results provide valuable insights for the realization of high-efficiency and high-stability PeLEDs for lighting and display applications.