Emergence of a Lanthanide Chalcogenide as an Ideal Scintillator for a Flexible X-ray Detector.

The development of high-performance X-ray detectors requires scintillators with fast decay time, high light yield, stability, and X-ray absorption capacity, which are difficult to achieve in a single material. Here, we present the first example of a lanthanide chalcogenide of LaCsSiS ₄  : 1 % Ce ³⁺ that simultaneously integrates multiple desirable properties for an ideal scintillator. LaCsSiS ₄  : 1 % Ce ³⁺ demonstrates a remarkably low detection limit of 43.13 nGy _air  s ^-1 and a high photoluminescence quantum yield of 98.24 %, resulting in a high light yield of 50480±1441 photons/MeV. Notably, LaCsSiS ₄  : 1 % Ce ³⁺ exhibits a fast decay time of only 29.35±0.16 ns, making it one of the fastest scintillators among all lanthanide-based inorganic scintillators. Furthermore, this material shows robust radiation and moisture resistance, endowing it with suitability for chemical processing under solution conditions. To demonstrate the X-ray imaging capacity of LaCsSiS ₄  : 1 % Ce ³⁺ , we fabricated a flexible X-ray detector that achieved a high spatial resolution of 8.2 lp mm ^-1 . This work highlights the potential of lanthanide chalcogenide as a promising candidate for high-performance scintillators.
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