Hydrochloric Acid-Assistant Powder-to-Powder Strategy for Synthesis of High-Quality Te 4+ -Doped Cs 2 ZrCl 6 Perovskite Microcrystals for X-ray Imaging

Vacancy-ordered double perovskites have emerged as promising scintillator materials for X-ray imaging applications. However, they typically necessitate the sophisticated synthetic approaches and exhibit weak emission. Here, an uncomplicated, large-scale, and cost-effective solution synthesis of Te⁴⁺-doped Cs₂ZrCl₆ double perovskite was adopted. Temperature-dependent photoluminescence study on Te⁴⁺-doped Cs₂ZrCl₆ revealed an abnormal negative thermal quenching phenomenon with an increase in temperature. During this process, as the carriers obtain sufficient thermal energy, they can participate in radiative recombination after escaping the trap states, thereby increasing the photoluminescence intensity. Te⁴⁺-doped Cs₂ZrCl₆ microcrystals exhibit highly efficient yellow photoluminescence with a photoluminescence quantum yield of 82% and robust stability, and they are used as scintillators to demonstrate a notable light yield of 24,415 photons MeV^-1 and spatial resolution of 8 lp mm^-1. It is believed that this scintillator screen shows potential for use in X-ray imaging.