Highly Stable Organic Antimony Halide Crystals for X-ray Scintillation

Abstract

Scintillators are utilized for X-ray detection in many important fields ranging from homeland security to health care. Developing low-cost, high-performance scintillation materials to address the issues of existing commercially available ones is of great interest. Recently, organic metal halide hybrids have emerged as highly promising luminescent materials with excellent optical properties and low-temperature solution processability. Herein, we report a zero-dimensional organic metal halide hybrid, (PPN)2SbCl5 (PPN = bis(triphenylphosphoranylidene)ammonium cation), as an X-ray scintillation material with high light yield and exceptional environmental stability. Our study shows that (PPN)2SbCl5 single crystals prepared by solution growth exhibit visible photoluminescence with a quantum efficiency of 98.1%. When excited by X-rays, (PPN)2SbCl5 single crystals exhibit radioluminescence with a near-perfect linearity over a large range of X-ray dose rates and a light yield of ∼49000 ph MeV–1, which is comparable to that of a commercial CsI(Tl) scintillator (∼54000 ph MeV–1). Moreover, the detection limit of (PPN)2SbCl5 (191.4 nGyair s–1) is much lower than the required value for regular medical diagnostics (5.5 μGyair s–1). (PPN)2SbCl5 single crystals also display remarkable stability, with little-to-no change in properties after storage under ambient conditions for 2 years.