A Super‐Bright and Temperature‐Inert Au Complex Scintillator With Thermally Stimulated Delayed Phosphorescence Characteristic

ABSTRACT Scintillators serve as crucial core materials in high‐energy radiation sensors. Molecule‐based scintillators, one of the important kind of scintillators, have demonstrated outstanding advantages, such as high water‐oxygen stability, low cost, and low toxicity. However, limited exciton utilization and luminescence efficiency have an impact on the radioluminescence properties of materials, severely limiting the development of molecule‐based scintillators. In this work, the first thermally stimulated delayed phosphorescence (TSDP) molecule‐based scintillator ( Au(TFPP) 3 ) was reported. Spin‐allowed reverse internal conversion (RIC) of triplet excitons occurs in the TSDP process, leading to efficient utilization of thermally sensitive triplet excitons and overcoming the significant temperature effect of scintillators. As a result, Au(TFPP) 3 not only has an ultrahigh photoluminescence quantum yield (PLQY) exceeding 99% but also has an excellent light yield (LY) as high as 99475 ± 275 photons MeV −1 . More importantly, all these luminescence properties are temperature independent over a very wide range from 100 to 370 K. The super‐bright and temperature‐inert characteristics render Au(TFPP) 3 highly suitable for ionising radiation detection, and Au(TFPP) 3 has been effectively applied in low‐dose x‐ray variable‐temperature imaging and α/β particle detection.