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.