Regulating the Liquid-to-Solid Transition of a Solvent-Coordinated Metal Halide for Low-Temperature-Processed Pixelated Scintillators

Embedding large-refractive-index metal halides into small-refractive-index matrices to create pixelated scintillators with a waveguide structure holds great promise for next-generation X-ray detectors. However, the fabrication of these pixelated scintillators remains challenging. Herein, a solvent compensation and seed-assisted method is developed to enable reversible liquid-to-solid transitions of a solvent-coordinated metal halide (SMH) while preserving its scintillation properties under a vacuum. This allows the SMH to be liquefied with good flowability at 90 °C and facilitates its vacuum infiltration into organic matrices with vertically aligned pores. Consequently, low-temperature-processed pixelated scintillators are reported for the first time which show good flexibility and effective light confinement, achieving a spatial resolution approaching the theoretical limit.