Tailoring Molecular Dimensions of Cesium Lead Bromide Perovskites with Varying Compositions of Oleic Acid and Oleylamine

摘要

The evidence on deciphering nucleation and growth of cesium lead halideperovskite crystals, and establishing the phase diagram of cesium lead halideperovskites of different dimensions is still lacking. In this work, a facilemethod for the synthesis of cesium lead bromide crystals of differentmolecular level dimensions at room temperature is presented by varying theOA/OAm ratios without changing the proportions of Cs and Pb precursors.Bromide ions are gradually released in the systems through the gamma-rayradiation chemistry of bromobenzene. As the volume ratios of OA/OAmincrease, different products such as CsBr, Cs_4PbBr_6 (0D), white -CsPbBr_3(1D), -CsPbBr_3 (3D) associated with PbBr_2 sheets, and -CsPbBr_3 areobtained in order. 1D -CsPbBr3 can be transformed into 2D CsPb_2Br_5through CsBr stripping in water. The phase diagram established in this workis helpful for understanding the nucleation and growth mechanism ofCs–Pb–Br perovskite crystals of different dimensions. The nucleation ofCs–Pb–Br perovskite crystals is driven by the supersaturation of either CsBr orPbBr_2 caused by varying OA/Oam ratios, i.e., 0D Cs_4PbBr_6 at thesupersaturation of CsBr, while 3D -CsPbBr3 at the supersaturation of PbBr_2.1D perovskite is the intermediate state between 0D and 3D perovskites.