X-ray detection, which plays an important role in medical and industrial fields, usually relies on inorganic scintillators to convert X-rays to visible photons; although several high-quantum-yield fluorescent molecules have been tested as scintillators, they are generally less efficient. High-energy radiation can ionize molecules and create secondary electrons and ions. As a result, a high fraction of triplet states is generated, which act as scintillation loss channels. Here we found that X-ray-induced triplet excitons can be exploited for emission through very rapid, thermally activated up-conversion. We report scintillators based on three thermally activated delayed fluorescence molecules with different emission bands, which showed significantly higher efficiency than conventional anthracene-based scintillators. X-ray imaging with 16.6 line pairs mm⁻¹ resolution was also demonstrated. These results highlight the importance of efficient and prompt harvesting of triplet excitons for efficient X-ray scintillation and radiation detection.

X射线检测在医学和工业领域有着重要的作用，通常依靠无机闪烁体将X射线转化为可见光子；尽管已经测试了几种高量子产率荧光分子作为闪烁体，但它们通常效率较低。高能辐射可以使分子电离并产生二次电子和离子。结果，产生了大部分三重态，它们充当闪烁损耗通道。在这里，我们发现 X 射线诱导的三线态激子可以通过非常快速的热激活上转换用于发射。我们报告了基于三种具有不同发射带的热激活延迟荧光分子的闪烁体，其效率明显高于传统的蒽基闪烁体。X 射线成像与 16。^-1分辨率也得到证明。这些结果突出了有效和迅速收集三线态激子对于有效的 X 射线闪烁和辐射检测的重要性。