Through‐Space Charge‐Transfer Organogold(III) Complexes Enable High‐Performance X‐ray Scintillation and Imaging

Organic scintillators have recently attracted growing attention for X‐ray detection in industrial and medical applications. However, these materials still face critical obstacles of low attenuation efficiency and/or inefficient triplet exciton utilization. Here we developed a new category of organogold(III) complexes, Tp‐Au‐1 and Tp‐Au‐2, through adopting a through‐space interaction motif to realize high X‐ray attenuation efficiency and efficient harvesting of triplet excitons for emission. Thanks to the efficient through‐space charge transfer process, this panel of complexes achieved higher photoluminescence quantum yield and shorter radiative lifetimes compared with the through‐bond reference complexes. Inspiringly, these organogold(III) complexes exhibited polarity‐dependent emission origins: thermally activated delayed fluorescence and/or phosphorescence. Under X‐ray irradiation, Tp‐Au‐2 manifested intense radioluminescence together with a record‐high scintillation light yield of 77,600 photons MeV‐1 for organic scintillators. The resulting scintillator screens demonstrated high‐quality X‐ray imaging with >16.0 line pairs mm–1 spatial resolution, outstripping most organic and inorganic scintillators. This finding provides a feasible strategy for the design of superior organic X‐ray scintillators.