Abstract
Cesium-based lead-free double perovskite materials (Cs(2)AgBiBr(6)) have garnered significant attention in the X-ray detection field due to their environment friendly characteristics. However, their substantial ion migration properties lead to large dark currents and detection limits in Cs(2)AgBiBr(6)-based X-ray detectors, restricting the detection performance of the device. In terms of process technology, ultrasonic spraying is more suitable than a spin-coating method for fabricating large-area, micron-scale perovskite thick films, with higher cost-effectiveness, which is crucial for X-ray detection. This work introduces a BA(+) (BA(+) = CH(3)CH(2)CH(2)CH(2)NH(3) (+), n-butyl) source into the precursor solution and employs ultrasonic spraying to fabricate quasi-two-dimensional structured polycrystalline (BA)(2)Cs(9)Ag(5)Bi(5)Br(31) perovskite thick films, developing a low-cost, eco-friendly X-ray detector with low dark current density and low detection limit. Characterization results reveal that the ion migration activation energy of (BA)(2)Cs(9)Ag(5)Bi(5)Br(31) reaches 419 meV, approximately 17% higher than that of traditional three-dimensional perovskites, effectively suppressing perovskite ion migration and subsequently reducing the dark current. The (BA)(2)Cs(9)Ag(5)Bi(5)Br(31)-based X-ray detectors exhibit high resistivity (about 1.75 × 10(10) Ω cm), low dark current density (66 nA cm(-2)), minimal dark current drift (0.016 pA cm(-1) s(-1) V(-1)), and detection limit (138 nGy(air) s(-1)), holding considerable promise for applications in low-noise, low-dose X-ray detection.