Radiophotoluminescent organic materials based on photoswitchable fluorescent diarylethene derivatives

Photochromism refers to reversible changes in a material’s optical absorption and reflectance properties which are triggered by the absorption of a photon. This property can be useful in radiation imaging applications if such changes can be induced by ionizing radiation. The X-ray-induced isomerization of a photoswitchable fluorescent diarylethene-based material, 1,2-bis(2-methyl-6-phenyl-1-benzothiophen-1,1-dioxide-3-yl)perfluorocyclopentene (1a), was investigated with the aim of developing tissue equivalent imaging sensor materials. When 1a was irradiated with X-rays, the fluorescence intensity at 520 nm increased, which is consistent with isomerization processes. This work represents the first fabrication of an organic radiophotoluminescence material based on the photochromic molecule 1a. The resulting materials were sensitive to X-rays for doses in the range of 0.1–10 kGy and exhibited a linear, dose-dependent response.