Probing molecule-like isolated octahedra via—phase stabilization of zero-dimensional cesium lead halide nanocrystals

Abstract

Zero-dimensional (0D) inorganic perovskites have recently emerged as an interesting class of material owing to their intrinsic Pb 2+ emission, polaron formation, and large exciton binding energy. They have a unique quantum-confined structure, originating from the complete isolation of octahedra exhibiting single-molecule behavior. Herein, we probe the optical behavior of single-molecule-like isolated octahedra in 0D Cesium lead halide (Cs 4 PbX 6 , X = Cl, Br/Cl, Br) nanocrystals through isovalent manganese doping at lead sites. The incorporation of manganese induced phase stabilization of 0D Cs 4 PbX 6 over CsPbX 3 by lowering the symmetry of PbX 6 via enhanced octahedral distortion. This approach enables the synthesis of CsPbX 3 free Cs 4 PbX 6 nanocrystals. A high photoluminescence quantum yield for manganese emission was obtained in colloidal (29%) and solid (21%, powder) forms. These performances can be attributed to structure-induced confinement effects, which enhance the energy transfer from localized host exciton states to Mn 2+ dopant within the isolated octahedra.