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

The structure of CsPbI 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 CsPbI NCs by regulating structural rigidity under the synergistic effect of Mg and AcO ions. The introduced AcO and Mg ions increase surface steric hindrance and defect formation energy, which enhances the structural rigidity of the perovskite. As a result, the CsPbI 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 CsPbI 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 CsPbI NCs exhibit a maximum luminance and an EQE of 3281 cd m and 13.2%, respectively, which are significantly improved compared with those of unmodified CsPbI NC LEDs.