Multiaxial Aromatic‐Based Photoferroelectric Induced by Synergistic Intermolecular Interactions for Multidirectional Self‐Powered X‐Ray Detection

Photoferroelectrics coupling spontaneous polarization and remarkable semiconductor attributes have emerged as promising candidates for self-powered X-ray detection. However, the effective construction of multiaxial aromatic photoferroelectrics for stable multidirectional self-powered X-ray detection remains a great blank. Herein, we report for the first time the successful design of a multiaxial aromatic-based photoferroelectric, (4Br2FBZ)₂PbBr₄ (4Br2FBZ = 4-bromo-2-fluorobenzylammonium), through synergistic noncovalent interactions of hydrogen bonding and fluorine-π, which achieves a stable multidirectional self-powered X-ray detection. Notably, the aromatic cations rotate driven by synergistic molecular interactions to form a T-shaped stacking architecture, resembling interlocking puzzle pieces. This oriented arrangement generates electric dipoles, inducing four equivalent polarization directions, which endow (4Br2FBZ)₂PbBr₄ with a large spontaneous polarization of 4.48 µC cm^-2 and a high Curie temperature of 408 K. The combination of its biaxial nature and strong intermolecular interaction network, self-powered X-ray detectors assembled along two polar axes demonstrate high sensitivities (181.7 and 175.3 µC Gy^-1 cm^-2), and exceptional detection stability. Strikingly, the polycrystalline ferroelectric film also exhibits excellent self-powered X-ray detection behavior due to its biaxial ferroelectricity, indicating the potential for next-generation flexible and thin-film integrated devices.