Flexible strontium-based metal–organic framework scintillation screens for high-resolution X-ray imaging

Abstract

Scintillators have been widely used in medical examinations, security inspections, aerospace and other applications with the ability to convert X-rays into UV/visible light. However, it remains a challenge to design and synthesize scintillators that feature low cost, high stability and easy preparation into flexible films. Here, we prepared a new 3D MOF [Sr₂(DOBPDC)₂(DMF)]_n1 by a short-cycle solvothermal method. Due to the synergistic contribution of the heavy metal and luminous organic functional motifs, compound 1 shows a higher X-ray responsive sensitivity than commercial scintillators BaF₂ and PbWO₄. The light yield of 1 is superior to those of some of our previously reported lead-based MOF scintillators at the same dose rates. The scintillation mechanism was elucidated using optical spectra and theoretical calculations. Benefiting from the strong connection between the metal atom and the rigid organic ligand, the structure and scintillation intensity of 1 remain almost unchanged while being immersed in water for 30 d, which confirms its outstanding water resistance. Meanwhile, the flexible scintillation screen 1-film was prepared by knife coating, and X-ray imaging with a spatial resolution of 5 lp mm⁻¹ was achieved. The 1-film also shows high resistance to fatigue, irradiation and humidity, and also maintains favorable X-ray imaging quality after being stored under ambient conditions for 30 d. This work provides new insight for the design and synthesis of stable and efficient MOF-based scintillators used in flexible scintillation screens.