Synergistic crystallization regulation and defect passivation for growth of high-quality perovskite single crystals towards ultrasensitive X-ray detection

Organic-inorganic hybrid perovskite single crystals are the most promising candidates for X-ray detection. However, the growth of high-quality large-size single crystals is still challenging. In this work, a passivator-assisted crystallization method is proposed to grow high-quality MAPbBr3 single crystals with an area larger than 400 mm2. With 4-trifluoromethyl phenylammonium bromide (CF3-PABr) as a passivator, the generated CF3-PA+ can be adsorbed on growing crystal surfaces via not only the interaction between -NH3+ and Br-, but also the coordination between -CF3 and Pb2+. Therefore, the crystal growth rate is significantly reduced and defect formation is effectively suppressed. Compared with the optimized control crystal, the MAPbBr3 single crystal grown with CF3-PABr shows effectively suppressed ion migration and a 4-fold larger mobility-lifetime product, enabling a record high X-ray sensitivity of 10.88 x 104 mu C Gyair-1 cm-2 and a low detection limit of 1.3 nGyair s-1. This work would help in optimizing the growth of solution-based perovskite single crystals and promoting their commercial applications. This report demonstrates a method of synergistic defect passivation and crystallization regulation, which can significantly improve crystal quality and promote X-ray detector performance.