Chemical bath deposition of AgBiS2 films for visible and X-ray detection

AgBiS2 possesses high absorption coefficient from ultra-violet to near-infrared, decent charge transport and superior materials stability, which has emerged as a promising candidate in the field of optoelectronics. However, efficient AgBiS2-based devices are mostly based on AgBiS2 quantum dots and precursor methods, which require either long preparation time and complex synthetic steps or inert atmosphere protection. To address these issues, we developed a novel and facile chemical bath deposition approach to deposit highly crystallized, uniform AgBiS2 thin films with decent optoelectronic properties. We also fabricated AgBiS2 heterojunction photodetectors based on this method, and achieved high responsivity covering the whole range of visible and near-infrared, fast response speed of ∼960 ns, and high specific detectivity of 8 × 1011 Jones and outstanding device stability. More importantly, we first demonstrated the device performance under X-ray illumination and observed decent sensitivity, implying great potential for low-cost, solution-processable X-ray detectors.