Chiral-Polar Alternating Cation Intercalation-Type Perovskite Enables Sensitive Self-Driven X-ray Detection with an Ultralow Detection Limit.

Metal halide perovskites (MHPs) have shown great potential for direct X-ray detection, but achieving high sensitivity without external bias remains challenging. Chiral-polar alternating cation intercalation (ACI)-type MHPs, with excellent optoelectronic properties and a robust chirality-induced bulk photovoltaic effect (BPVE), offer a promising platform for self-driven X-ray detection. Herein, impressive self-driven X-ray detection performance was achieved by utilizing chiral-polar 2D ACI-type perovskite single crystals of (-PPA)PAPbBr (; -PPA = -1-phenylpropylamine; PA = propylamine). The chiral -PPA cations induce the crystallization of in the chiral-polar space group 2, wherein its spontaneous electric polarization further induces a strong BPVE. Consequently, shows remarkable radiation photovoltaics of 0.75 V, which endows its excellent self-driven X-ray detection with a high sensitivity of 417.2 μC Gy cm and a low detection limit of 24.1 nGy s, meeting the state-of-the-art level by leveraging its intrinsic photovoltaic effect. These findings highlight the huge potential of chiral-polar ACI-type MHPs in self-driven X-ray detection applications.