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

Abstract

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 × 10⁴ μC Gy_air⁻¹ cm⁻² and a low detection limit of 1.3 nGy_air s⁻¹. This work would help in optimizing the growth of solution-based perovskite single crystals and promoting their commercial applications.