The scaling of the ligand concentration and Soret effect induced phase transition in CsPbBr3 perovskite quantum dots†
An intelligent chemistry strategy based automated machine is applied for the study of the phase transition in CsPbBr3 quantum dots (QDs). With an in situ photoluminescence (PL) signal detection and analysis module, oleyl amine (OLA) and oleyl acid (OA) ligand concentration dependent diffusion pictures are well derived, a three-stage power-law scaling is disclosed on the ligand concentration dependent growth, and a phase transformation from CsPbBr3 to Cs4PbBr6 QDs is confirmed. Based on the experimental analysis associated with the G0W0–BSE calculation, we confirmed that there is no significant PL signal in the pure Cs4PbBr6 structure. With a steady temperature control module, we find that the ligand concentration and the Soret effect are isomorphic for the mass flux in the QD nucleation and phase transformation. We find that the activity of surface states can be essential for the size dependence of the Soret effect in a general way.