Synergistic Band/Trap Engineering in RbCdF3:Mn2+ for High-Resolution Dual-Mode X-Ray Imaging: Ghost-Free Real-Time and Multi-Cycle Time-Delay

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 ( 2 E u C d · − V C d ′ ′ $2Eu_{Cd}^ \cdot - V_{Cd}^{^{\prime\prime}}$ ) 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.