The emerging pseudohalide metal-free perovskite (pseudohalide–MFPs) X-ray detector caters to the demands of timely mobile diagnosis owing to its lightweight, flexibility, and cost-effectiveness. However, the performance of these devices is severely limited by poor X-ray absorption, ultra-wide band gap, relative instability, and their unknown biotoxicity. Herein, we construct heavy atom covalent bonds (C–Br/Cl) on the A-site organic cation to reinforce component coordination to modulate X-ray absorption and band gap in pseudohalide–MFPs and further enhance its stability. Molecular dynamics simulations demonstrate that the introduction of halogen atoms can strengthen hydrogen bonding interactions, thereby improving the coordination between different components. The resultant (MDABCOBr)–NH₄(BF₄)₃ (MDABCO = N-methyl-N’-diazabicyclo[2.2.2]octonium) single crystal significantly increases X-ray absorption cross-section and crystalline density (from 1.728 to 1.950 g cm⁻³), and synergistically realizes the band nature modulation (from 7.4 to 5.5 eV) and enhanced ionic migration inhibition (628 meV) with optimized stability. As such, our X-ray detectors realized a sensitivity of 2377 μC Gy_air⁻¹ cm⁻², an ultralow detection limit of 50.1 nGy_air s⁻¹, and impressive operation stability. Moreover, cytotoxicity assay confirmed the compatibility of pseudohalide metal-free perovskite. Finally, within this framework, we successfully fabricate the (MDABCOBr)–NH₄(BF₄)₃-based flexible device to create an ideal in vitro wearable X-ray detection.

新兴的赝卤化物无金属钙钛矿（赝卤化物-MFP）X射线探测器因其轻便、灵活和成本效益而满足了及时移动诊断的需求。然而，这些器件的性能受到X射线吸收差、超宽带隙、相对不稳定以及未知的生物毒性的严重限制。在此，我们在A位有机阳离子上构建重原子共价键（C-Br/Cl）来增强组分配位，从而调节赝卤化物-MFP的X射线吸收和带隙，并进一步增强其稳定性。分子动力学模拟表明，卤素原子的引入可以增强氢键相互作用，从而改善不同组分之间的配位。所得的(MDABCOBr)–NH ₄ (BF ₄ ) ₃ (MDABCO = N-甲基-N'-二氮杂双环[2.2.2]辛鎓)单晶显着增加了X射线吸收截面和晶体密度(从1.728增加到1.950) g cm ^-3 ），并协同实现能带性质调制（从7.4到5.5 eV）和增强的离子迁移抑制（628 meV）并优化稳定性。因此，我们的X射线探测器实现了2377 μC Gy _Air ^-1 cm ^-2的灵敏度、50.1 nGy _Air s ^-1的超低检测限以及令人印象深刻的运行稳定性。此外，细胞毒性测定证实了不含拟卤化物金属的钙钛矿的相容性。最后，在此框架内，我们成功制造了基于(MDABCOBr)–NH ₄ (BF ₄ ) ₃的柔性器件，以创建理想的体外可穿戴X射线检测。