Abstract: Perovskite single crystals (PSCs) have attracted significant interest for next-generation radiation detection. However, the lack of in-depth crystal growth kinetics of PSCs limits the development of high-quality PSCs. Here, with an in-situ real-time monitoring system for MAPbBr₃ PSCs growth during the antisolvent vapor-assisted crystallization (AVC) process, the growth curves of MAPbBr₃ PSCs are obtained and the growth kinetics are theoretically modeled. Two important factors, including antisolvent vapor flux and initial precursor concentration, have been investigated experimentally for their impacts on crystal quality. By controlling the antisolvent vapor flux, the nucleation of PSCs at the container-solution interface can be regulated; while by controlling the initial precursor concentration, the crystal quality can be improved. The optimized MAPbBr₃ PSCs exhibited significantly high qualities, with the narrowest reported full width at half maximum (0.00637°) of X-ray diffraction rocking curve as reported, a trap-state density as low as 2.12 × 10¹⁰ cm^-3, and a mobility-lifetime (μτ) product of 1.4 × 10^-2 cm² V^-1. The fabricated X-ray detectors demonstrated optimal performance at an electric field of 20 V/mm, with a sensitivity of 9.02 × 10³ μC Gy^-1 cm^-2 and the lowest detectable dose rate of 0.08 μGy s^-1 under irradiation with continuum X-ray energy up to 20 keV. This work provides valuable insights for the development of high-quality PSCs for direct radiation detection.

Key words: Antisolvent vapor-assisted crystallization, Growth rate measurement, Crystal growth kinetics, Low-concentration precursor, X-ray detectors