In March 2022, Wu Dan's research group and cooperative units, assistant professor of our institute, conducted the "In Situ Growth Mechanism for High-Quality Hybrid Perovskite Single-Crystal Thin Films with High Area to Thickness Ratio: Looking for the Sweet Spot)" publishes the latest research in the comprehensive journal Advanced Science (Q1, IF:16.806). Assistant Professor Wu Dan of Shenzhen University of Technology is the co-corresponding author of the article. The other two co-corresponding authors are Associate Professor Wang Kai of southern university of science and technology and professor Fuqian Yang of Kentucky University.

Perovskite single crystal materials have the advantages of no grain boundary, low defect density, long carrier life, good stability, etc., known as a promising photoelectric material, in LED, laser, photoelectric detection, solar cells and other fields have a wide range of application prospects, and the in situ growth of high-quality perovskite single crystal film on the transmission layer is an important development trend. The research team systematically studied the characteristics of perovskite single crystal thin films in different growth environments, combined with theoretical analysis, and determined the three factors and optimal points that affect the in situ growth of the transport layer of perovskite single crystal films, namely the low interface energy between the precursor solution and the transport layer, the slow heating rate and the moderate precursor solution concentration.Finally, a high-quality MAPbBr3 perovskite single crystal film with a defect density of only 2.68 × 1010 cm-3 and a record area-thickness ratio of 1.94×104 mm (film thickness of 540 nm) was prepared. Thanks to this, the perovskite single crystal film has a carrier mobility of up to 141 cm2V-1S-1, which is the highest value in the literature report of MAPbBr3 perovskite single crystal films, and has a long-term crystal structure stability of more than 360 days. At the same time, this work also confirms that this "best point" is also suitable for in situ growth of other perovskite single crystal films in the transport layer, including MAPbI3, (PEA) 2PbI4 and (PEA) 2PbBr4, indicating that the growth conditions have a certain universality.

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https://onlinelibrary.wiley.com/doi/10.1002/advs.202104788?af=R

Fig. Adjustment of doping concentration of perovskite active layer, construction of built-in electric field at interface, and performance test of upright and inverted photodetectors