Synergistic regulation effect of magnesium and acetate ions on structural rigidity for synthesizing an efficient and robust CsPbI3 perovskite toward red light-emitting devices

Abstract

The structure of CsPbI₃ nanocrystals (NCs) with excellent photoelectric properties easily collapses, which hinders their application in light-emitting diodes (LEDs). Herein, we accomplished the synthesis of efficient and stable CsPbI₃ NCs by regulating structural rigidity under the synergistic effect of Mg²⁺ and AcO⁻ ions. The introduced AcO⁻ and Mg²⁺ ions increase surface steric hindrance and defect formation energy, which enhances the structural rigidity of the perovskite. As a result, the CsPbI₃ NCs display an outstanding photoluminescence quantum yield of 95.7%, in conjunction with reduced defect state density, balanced carrier injection, and distinguished conductivity. Remarkably, the modified CsPbI₃ NCs exhibit excellent stability under ambient conditions for 180 days and can even survive when the temperature reaches 150 °C. Given their enhanced structural rigidity, LEDs made from these modified CsPbI₃ NCs exhibit a maximum luminance and an EQE of 3281 cd m⁻² and 13.2%, respectively, which are significantly improved compared with those of unmodified CsPbI₃ NC LEDs.