Butylammonium-Based Chiral 2D Perovskite Single Crystals for Efficient UV Circularly Polarized Light Differentiation and High-Performance X-ray Detection

Chiral two-dimensional perovskites are a promising candidate for circularly polarized light (CPL) detection, which combine inherent chirality with excellent optoelectronic properties, while exhibiting good structural stability. In this paper, a pair of chiral two-dimensional perovskites, single-crystal R/S-(BrBA)₂PbBr₄ are synthesized using a cooling crystallization solution method. Due to the introduction of chiral organic molecules, the inorganic layers undergo significant distortion and deformation. The large optical bandgap of the materials and the vertically oriented electrode structure of the detector result in an extremely low dark current, combined with circular dichroism (CD) spectroscopy and a photocurrent anisotropy factor of 0.14 at 405 nm, and demonstrate the good potential of the materials for detecting circularly polarized light in the ultraviolet band. In addition, the unique semiconductor properties enable it to have a detection sensitivity of 531.33 μC Gy^-1 cm^-2 (at 0.15 V/μm) and a detection limit of less than 100 nGy s^-1 in X-ray detection, which is far lower than that of requirements in conventional medical diagnosis (5.5 μGy s^-1). The final imaging experiments have also verified its feasibility for application in X-ray imaging.