Continuous Metal-Organic Framework Thin Films for High-Resolution X-Ray Imaging

In the realm of scintillator material science, the significance of scintillator screens lies in their ability to enhance imaging resolution and X-ray sensitivity.1,2 These two factors are of utmost importance for achieving accurate medical diagnoses and treatments, improving safety inspections, and enabling comprehensive examinations of industrial equipment.3 Presently, the dominant methods employed for creating scintillator screens primarily involve high-temperature sintering, crystal growth, and polymer doping techniques. However, these methods come with stringent synthesis requirements and grapple with challenges related to achieving uniform and extensive growth across large surfaces while minimizing light scattering.4 The in-situ electrochemical synthesis of continuous metal-organic framework (MOF) thin films offer a solution that increases material density, reduces light dispersion, and ensures long-lasting durability. The tightly interconnected and precisely oriented growth structure of continuous MOF thin films results in a significant reduction in light scattering.5 Consequently, the inherent characteristic of diminished light dispersion holds great promise for enhancing spatial imaging resolution in X-ray scintillators.<br/>Herein, we present a versatile approach rooted in in-situ electrochemical-directed assembly, dedicated to crafting MOF thin films tailored for exceptional X-ray imaging capabilities. Through this electrochemical process, a series of coherent MOF thin films have been successfully synthesized, employing interconnected lanthanide metals and terephthalic acid linkers. This specific MOF thin film emerges as a standout contender, enabling high-resolution X-ray imaging while retaining X-ray sensitivity. This achievement is attributed to its superior material density, reduced light scattering, and simplified manufacturing procedure. Notably, this particular MOF thin film surpasses the majority of documented organic and traditional inorganic scintillators, achieving an X-ray imaging resolution exceeding 32 line pairs per millimeter (lp/mm). This research has the potential to elevate MOFs as highly efficient scintillators for X-ray imaging, opening up exciting opportunities in the fields of radiology and security screening applications.<br/>References<br/>1. Yi, L., Hou, B., Zhao, H., Tan, H. Q. & Liu, X. A double-tapered fibre array for pixel-dense gamma-ray imaging. Nat. Photon. 17, 494-500 (2023).<br/>2. Wang, J.-X. et al. Heavy-atom engineering of thermally activated delayed fluorophores for high-performance X-ray imaging scintillators. Nat. Photon. 16, 869-875 (2022).<br/>3. Chen, Q. et al. All-inorganic perovskite nanocrystal scintillators. Nature. 561, 88-93 (2018).<br/>4. Han, K. et al. Seed-crystal-induced cold sintering toward metal halide transparent ceramic scintillators. Adv. Mater. 34, e2110420 (2022).<br/>5. Zhou, S. et al. Asymmetric pore windows in MOF membranes for natural gas valorization. Nature. 606, 706-712 (2022).