Al ₄ B ₂ O ₉ :Tb ³⁺ Glass-Ceramic Scintillator for Antithermal Quenching X-ray Imaging in Deep-Earth Extreme Environments

In deep-earth environments, glass scintillators (GSs) can better withstand high temperature (>200 °C), high-humidity and other extreme conditions compared to crystal scintillators. However, due to their inherently high phonon energy and abundant defects, GSs are prone to thermal quenching (TQ), resulting in a low detection efficiency at elevated temperatures. To suppress TQ at high temperatures, an investigation into the mechanism of phonons and defects in the radioluminescence is conducted by introducing fluorides to create a low phonon environment and nanocrystallization to regulate a high proportion of shallow defect states. It is revealed that lower phonon energy effectively reduces energy dissipation during hot carrier relaxation, while shallow defect states facilitate carrier transport efficiency during migration to luminescent centers. Two strategies thereby collectively enhance radiative recombination. Based on the above, Al₄B₂O₉:Tb³⁺ glass ceramic (GC) with a lower phonon energy and dominant shallow defect states (0.74 eV) was successfully synthesized. It has achieved excellent anti-TQ performance (188% at 400 °C), high spatial resolution (20 lp mm^-1) and X-ray induced time-lapse imaging. This result has paved new avenues for GSs for applications in deep-earth environments.