Cesium Methylammonium Lead Iodide (Cs MA PbI ) Nanocrystals with Wide Range Cation Composition Tuning and Enhanced Thermal Stability of the Perovskite Phase.

Cesium methylammonium lead iodide (Cs MA PbI ) nanocrystals were obtained with a wide range of A-site Cs-MA compositions by post-synthetic, room temperature cation exchange between CsPbI nanocrystals and MAPbI nanocrystals. The alloyed Cs MA PbI nanocrystals retain their photoactive perovskite phase with incorporated Cs content, x, as high as 0.74 and the expected composition-tunable photoluminescence (PL).