Science News: 2021 Advanced Materials, How Mixed Perovskite Crystals Improve Structural Stability and Photodetection

　　Advanced Materials (IF 30.849) published a study by Ahmed L. Abdelhady, Liberato Manna, Roman Krahne of Italian Institute of Technology and Anna Moliterni of The National Research Council of Italy (CNR) et al. in December 2021. The authors grew mixed dimethylammonium/ methylammonium lead tribromide (DMA/MAPbBr₃) crystals by solvent acidolysis crystallization technique. It was found that not only the highest dimethylammonium incorporation of 44% could be achieved, but also the 3D cubic perovskite phase could be maintained. The article also further compared with the performance of MAPbBr₃.

1. Compared to MAPbBr₃, these mixed perovskite crystals show suppression of orthorhombic phase and lower tetragonal-to-cubic phase-transition temperature.
2. Different behaviors can be found in the temperature-dependent photoluminescence properties of MAPbBr₃ and mixed DMA/MAPbBr3 crystals due to the different organic cation dynamics governing the phase transition(s).
3. The authors used a lateral photodetector, at room temperature, the mixed crystals have a higher detectivity than the MAPbBr₃ crystals due to structural compression and reduced surface trap density.
4. Below the phase-transition temperature (at 200 K), the detectivity of the mixed-crystal devices is significantly improved, but only a very small change is observed for the MAPbBr₃ devices.