Scalable Glassy X-Ray Scintillators with Bright Singlet-Triplet Hybrid Self-Trapping Excitons

Abstract Size-scalable X-ray scintillators with high transparency and robust photon yield allow for imaging large objects with greater precision and detail. Solution-processable scintillators, typically crafted from quantum dots (QDs), are promising candidates for highly efficient scintillation applications. However, the restricted size, low transparency, and dark nature of triplet excitons in QD-based scintillators lead to less efficient X-ray imaging for large objects requiring high resolution. Herein, we demonstrate a meter-scale glassy ZnO QD scintillator with a visible range transmittance exceeding 96% at a thickness of 0.5 mm, showcasing bright singlet/triplet hybrid self-trapping hybrid excitons (STEs). The quantum yields (QYs) of singlet excitons and triplet excitons are 44.7% and 26.3%. Benefiting from a large Stokes shift and bright triplet excitons, the scintillator has a negligible self-absorption and elevated photon yields. Additionally, the scintillator exhibits exchange invariance, demonstrating identical optical performance upon exchanging the coordinates (r) of the QDs. Featuring bright singlet/triplet hybrid STEs and high transparency, the scintillator achieves high resolution X-ray imaging of 42 line pairs per millimeter (42 lp mm⁻¹) at a meter scale. Moreover, demonstrations of 5000 cm² X-ray imaging and real-time dynamic X-ray imaging are presented. The lowest detectable dose rate for X-ray detection is as low as 38.4 nGy s⁻¹. This work provides a novel sizable and transparent scintillator with bright singlet/triplet hybrid excitons, showcasing their potential in high-resolution and sizable object X-ray imaging.