Improving the Stability of α-CsPbI Nanocrystals in Extreme Conditions Facilitated by Mn Doping.

The wide application of CsPbI nanocrystals (NCs) is limited due to their poor phase stability. We reported that Mn-CsPbI NCs have better optical performance and phase stability. With a suitable Mn/Pb ratio (5.0%), Mn-doped α-CsPbI NCs exhibited the best stability under UV irradiation, ethanol addition, and heating. Under UV irradiation and addition of ethanol, photoluminescence (PL) intensities of CsPbI NCs could be only preserved up to 35% (22 min UV irradiation) and 10% (ethanol addition), respectively, whereas, Mn-doped CsPbI (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-CsPbI NCs can be further applied to optoelectronic devices.