Temperature-Adaptive Organic Scintillators for X-ray Radiography

Organic phosphorescence or thermally activated delayed fluorescence (TADF) scintillators, while effective in utilizing triplet excitons, are sensitive to temperature changes, which can impact radioluminescence performance. In this study, we have developed a type of temperature-adaptive organic scintillator with phosphorescence and TADF dual emission. These scintillators can automatically switch modes with temperature changes, enabling efficient radioluminescence from 77 to 400 K. The highest photoluminescence quantum yield and light yield are 83.2% and 78,229 ± 562 photons MeV^-1 excited by a UV lamp and X-ray, respectively. Their detection limit is 51 and 23 nGy·s^-1 at room temperature and 77 K, respectively, which is lower than the standard dosage of 5.5 μGy s^-1 for X-ray diagnostics. Moreover, given the high spatial resolution of 21.7 l p mm^-1, we demonstrate their potential application in multiple-temperature X-ray radiography, offering promising new possibilities. This work opens a new route for developing organic scintillators to adapt to ambient temperature change and paves the way for their use in various temperature-sensitive radiography applications.