Highly luminescent antimony-based organic–inorganic hybrid halides for X-ray imaging and detection

Abstract

Scintillators can convert high-energy X-rays into low-energy detectable ultraviolet-visible-near-infrared photons, which show extensive practical applications in X-ray detection and imaging. Metal-based organic–inorganic hybrid halides (OIHHs) are expected to become substitutes for commercial scintillators due to their flexible tunability of structure and spectra, good solution processability, and excellent photophysical properties. Among them, antimony-based (Sb³⁺) OIHH scintillators have exhibited highly efficient photophysical properties and scintillation performance due to the high stereo active lone pairs of the ns² electron configuration. Herein, we synthesized a series of Sb³⁺-based (TEBA)₂SbCl_5−xBr_x (x = 0, 1, 2, 3, 4, 5) metal halides (TEBA: benzyltriethylammonium chloride) by regulating the ratio of halogen atoms (Cl/Br). (TEBA)₂SbCl_5−xBr_x scintillators all show broadband emission, large Stokes shifts and microsecond lifetimes. With the increase of the Br⁻ ion concentration, the photophysical properties and scintillation performance of (TEBA)₂SbCl_5−xBr_x have been tuned. Among the six Sb³⁺-based OIHHs, (TEBA)₂SbCl₃Br₂ exhibits the best scintillation performance with a high photoluminescent quantum yield of 73.83%, a high light yield of 15 000 photons MeV⁻¹, and a low detection limit of 50.1 nGy_air s⁻¹. Besides that, X-ray imaging based on a (TEBA)₂SbCl₃Br₂ scintillator screen presents a high spatial resolution of 10.4 lp mm⁻¹.