Novel Scintillator-Integrated Highly Sensitive Photonic Films for X-ray Detection via BaF₂ Energy Conversion

Ionizing radiation dosimetry is critical in medical and industrial applications, yet conventional dosimeters often lack visual readability and sufficient detection sensitivity. Current radiochromic photonic materials offer wavelength-based dose visualization but face complex fabrication. Here, we develop a novel X-ray-responsive photonic film by magnetically assembling the carbon-encapsulated Fe₃O₄ (Fe₃O₄@C) nanochains in a GelMA precursor encapsulated by BaF₂ plates. The BaF₂ scintillator converts X-rays to UV light, inducing GelMA cross-linking and volumetric contraction, which modulates structural color changes of photonic films. Finite element simulation analysis confirms that radiochromic behaviors stem from a reduction in interparticle spacing of Fe₃O₄@C nanoparticles (Fe₃O₄@C NPs) along the nanochains direction. The optimized film (B0.5/Fe4/1L/S-1) achieve a low detection threshold (6 Gy), high sensitivity (4.62 Gy), and linear dose-response (R² = 0.981, 0-10 Gy). This study integrates scintillator energy conversion with photonic structural color changes, enabling real-time, naked-eye X-ray dosimetry with potential applications in low-dose monitoring.