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

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)2SbCl5-xBrx (x = 0, 1, 2, 3, 4, 5) metal halides (TEBA: benzyltriethylammonium chloride) by regulating the ratio of halogen atoms (Cl/Br). (TEBA)2SbCl5-xBrx 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)2SbCl5-xBrx 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 nGyair 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. The photophysical properties and scintillation performance of Sb3+-based (TEBA)2SbCl5-xBrx OIHHs have been tuned through regulating the ratio of halogen atoms.