Influence of periodic flow field on synthesis of perovskite nanocrystals: Synthetic pathway and productivity

Here it was demonstrated that series–parallel reaction pathway for CsPbBr₃ and Cs₄PbBr₆ perovskite nanocrystals (PNCs) were selective by the periodic flow fields as well as precursor ratio. The periodic Taylor vortex flows (PTVFs) in a Couette-Taylor batch reactor (BR) were applied for controlling the synthetic pathway of PNCs and the random turbulent eddy flow (RTEF) in a stirred tank BR was also used for comparison. The PTVFs in the Couette-Taylor BR promoted not only the formation reaction of CsBr from the reaction between Cs-oleate (Cs-OA) and PbBr₂ but also the reaction between CsBr and the remained PbBr₂. As a result, the CsPbBr₃ and Cs₄PbBr₆ PNCs could be selectively formed according to the ratio of Cs-OA:PbBr₂ under the PTVFs in the Couette-Taylor BR, whereas they couldn't under the RTEF in the stirred tank BR. In addition, the production yield of CsPbBr₃ and Cs₄PbBr₆ PNCs in Couette-Taylor BR increased up to 30 % and 57 %, respectively, compared to their yield in the stirred tank BR due to the effective micro-mixing and shear dispersion of PNCs.