Improving the Stability of α‑CsPbI₃ Nanocrystals in Extreme Conditions Facilitated by Mn²⁺ Doping

The wide application of CsPbI₃ nanocrystals (NCs) is limited due to their poor phase stability. We reported that Mn²⁺-CsPbI₃ NCs have better optical performance and phase stability. With a suitable Mn/Pb ratio (5.0%), Mn²⁺-doped α-CsPbI₃ NCs exhibited the best stability under UV irradiation, ethanol addition, and heating. Under UV irradiation and addition of ethanol, photoluminescence (PL) intensities of CsPbI₃ NCs could be only preserved up to 35% (22 min UV irradiation) and 10% (ethanol addition), respectively, whereas, Mn²⁺-doped CsPbI₃ (5.0%) exhibited much improved stability, and their intensities could be preserved up to 70% (22 min UV) and 58% (ethanol), respectively. It should be noted that crystal-phase stability could be maintained at least 7 h even at 120 °C. We believe that the improved stability in extreme conditions for α-CsPbI₃ NCs can be further applied to optoelectronic devices.