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.
- Compared to MAPbBr3, these mixed perovskite crystals show suppression of orthorhombic phase and lower tetragonal-to-cubic phase-transition temperature.
- 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).
- 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.
- 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.
(a,b) Ultraviolet photoemission spectroscopy (UPS) measurments, (c) calculated band edge absorption profile from the diffuse reflectance spectra based on the empirical Kubelka-Munk function for MAPbBr3 and 44% DMA crystals, and (d) corresponding band structure.
According to the above results, the high detectivity of the mixed crystals is shown to be attractive for visible-light communication and space applications. More emphasis is placed on the importance of composition-engineered synthesis techniques for halide perovskites, which control their structural and optoelectronic properties.