Tuning intrinsic defects in γ-CuI by cation and anion doping

Abstract γ-CuI is a promising scintillator owing to the ultrafast decay time of 130 ps contributed by the near-band-edge emission. The luminescence properties of the γ-CuI are directly related to its intrinsic defects, such as Cu and I vacancies. In this context, tuning the intrinsic defects by cation and anion doping was proposed to improve the scintillation performance of γ-CuI. The structural properties of the dopants, including Li, Na, Mg, F, Cl and Br, were investigated by first-principles calculations. The Li, Na and Mg atoms were calculated to occupy the Cu site. The Cl and Br atoms turned out to replace the I atoms. Importantly, the Cu vacancies were created by Cl and Br dopants, and the I vacancies were eliminated through Li, Na, Mg, Cl and Br doping. These theoretical results were demonstrated by photoluminescence and X-ray excited luminescence spectra.