Additive Engineering for Ambient Blade‐Coated CsPbBr ₃ Films Enabling High‐Performance Self‐Powered X‐Ray Detection

Hybrid perovskite materials have recently emerged as a promising candidate in radiation detection research due to their superior charge carrier mobility and lower trap-state density. While most perovskite X-ray detectors typically rely on external bias for charge collection, the growing demand for efficient and energy-saving perovskite X-ray detectors has spurred extensive interest in self-powered devices, which offer high-performance, low power consumption, and enhanced portability. To date, most high-performance self-powered X-ray detectors rely on secondary crystal growth via post-deposition immersion in saturated solutions. Herein, we report a facile additive engineering strategy employing 4-trifluoromethyphenylammonium iodide (CF₃PhAI) to modulate perovskite crystallization, enabling single-step fabrication of microcrystalline CsPbBr₃ films with grain sizes up to 38.6 µm. This approach effectively passivates defects and suppresses ion migration in CsPbBr₃, reducing dark current drift by nearly two orders of magnitude from 4.135 × 10⁻¹² to 4.167 × 10⁻¹⁴ A s⁻¹. Moreover, the incorporation of a low-work-function aluminum (Al) top electrode significantly enhances the built-in electric field, yielding a remarkable zero-bias sensitivity of 1.3 × 10³ µC Gyair ⁻¹ cm⁻². This work accelerates the development of high-performance self-powered perovskite X-ray detectors toward practical applications.