Scintillation Performance of Mn(II)‐Doped Cs<sub>2</sub>NaBiCl<sub>6</sub> Double Perovskite Nanocrystals for X‐Ray Imaging Applications
V. Naresh, R. Ramaraghavulu, Kiran Gupta, Pil‐Ryung Cha, Nohyun Lee
Abstract
Abstract Lead‐free halide perovskite‐based X‐ray scintillators with high light yield (LY) and low detection limit (LOD) have become a growing subject of research interest due to their promising application in a wide range of areas, from security to healthcare. Herein, a modified hot injection method is employed to synthesize Mn(II)‐doped Cs 2 NaBiCl 6 double perovskite nanocrystals (DPNCs) and to examine their scintillating properties for application in X‐ray imaging and detection. The Mn(II)‐doped Cs 2 NaBiCl 6 DPNCs exhibit a broad orange photoluminescence (PL) band at 586 nm with a PL quantum yield of 10.6%, attributed to the 4 T 2g (4G) → 6 A 1g (6S) transition of Mn 2+ . Temperature‐dependent PL and time‐resolved PL spectra of 4.04% Mn(II)‐doped Cs 2 NaBiCl 6 demonstrate that the orange emission intensity initially reaches a maximum and subsequently decreases, while the decay lifetimes monotonically decrease with increasing temperature. This inconsistency can be due to the effect of the [MnCl 6 ] 4− octahedra and electron‐phonon coupling at elevated temperatures. Further, 0.05 mm thick Cs 2 NaBiCl 6 :4.04%Mn@poly(methyl methacrylate) scintillator film is synthesized with an LY of 28,350 photons MeV −1 and a LOD of 45.2 nGy air s −1 . Additionally, this film demonstrates good X‐ray imaging performance with a spatial resolution of 14.76 line pairs (lp) mm −1 and shows exceptional stability under prolonged X‐ray exposure.