Synergistic Band/Trap Engineering in RbCdF ₃ :Mn ²⁺ for High‐Resolution Dual‐Mode X‐Ray Imaging: Ghost‐Free Real‐Time and Multi‐Cycle Time‐Delay

ABSTRACT Conventional storage scintillators are plagued by rapid information fading during X‐ray real‐time imaging at room temperature, a consequence of intense X‐ray excited persistent luminescence (XEPL) from high‐density shallow traps. To address this limitation, we demonstrate a synergistic band/trap engineering strategy in RbCdF 3 :Mn 2+ via Cs + /Eu 3+ co‐doping. Specifically, Cs + doping narrows the bandgap, increasing the carrier density for radiative recombination and boosting the radioluminescence (RL) intensity to 1000%. In parallel, Eu 3+ doping introduces charge‐compensated defect clusters () that elevate the deep trap density to 933%. This synergistic optimization yields a high‐performance scintillator exhibiting an RL intensity of 625% relative to BGO, an ultra‐low detection limit of 102.3 nGy s −1 , and an ultra‐weak room‐temperature XEPL that is visually undetectable and weaker than commercial LuAG:Ce. Notably, the regulatory effect of this co‐doping strategy is demonstrated to be universal across the ABF 3 :Mn 2+ series. Furthermore, a flexible scintillator film fabricated from this material achieves an ultra‐high spatial resolution of 22.7 lp mm −1 , substantially surpassing most reported counterparts. It enables both ghost‐free X‐ray real‐time imaging and stable multi‐cycle X‐ray time‐delay imaging (XTDI) via thermal stimulation. This work establishes a versatile material design platform for high‐performance, low‐dose X‐ray imaging in both real‐time and delayed modes.