Anisotropic Two-Dimensional Perovskite Single Crystal for Improved X-Ray Detection Performance

The layered organic-inorganic hybridized perovskites are considered as new two-dimensional (2D) materials. They are emerging as promising direct X-ray detection candidates due to their excellent optoelectronic properties and working stability. The organic-inorganic alternating layered structure shows intrinsic stability and inhibiting ion migration, which derives from the contribution of the large organic molecular layers. However, the charge carrier transport is always limited by this organic barrier, resulting in the challenge of improving the sensitivity of 2D perovskite detectors. Here, we report the anisotropic response of hard X-ray detectors based on bulk high-quality 2D (FPEA)2PbI4 single crystals (SCs). Compared to the interlayer transmission between the (001) plane, the charge carriers exhibit higher transport efficiency along the (001) plane, resulting in a significant increase of sensitivity up to${1}.{06}\times {10}^{{4}}~\mu $C Gy$_{\text {air}}^{-{1}}$cm$^{-{2}}$, and low detection limit of 51 nGy s$^{-{1}}$. The anisotropic carrier transportation in different crystal orientations displays a new strategy to achieve high-performance 2D perovskite SCs X-ray detectors.