Solution-processed semiconductors have emerged as promising candidates for next-generation X-ray detectors, benefiting from their facile processing and tunable optoelectronic properties. However, the fabrication of thick junctions (>1 μm) is limited by poor stability and insufficient charge transport. To fill this gap, we report a sol-gel method to fabricate thick junctions based on Sb 2-x Bi x S 3 precursors. The charge carrier dynamics of antimony bismuth sulfide films were evaluated by multiple transient and steady-state techniques. It was found that Bi can modulate film morphology and thick film formation, and it also has an impact on boosting the charge transport properties. After optimization, low dark current, ultra-fast response, decent X-ray sensitivity, and high spatial resolution were achieved. The Sb 2-x Bi x S 3 -based thick junctions are stable under large bias voltage, high irradiance, and high temperature even underwater, indicating the potential for X-ray detection and imaging.
Metal halide perovskites exhibit great promise for utilization in X-ray detection owing to their excellent optoelectronic properties and high X-ray attenuation capabilities. However, fabricating large-area thick films for high-performance perovskite X-ray detection remains challenging. This study develops an in situ crystal growth and fusing-confined approach to prepare high-quality, large-scale perovskite quasi-monocrystalline thick junctions. The perovskite crystals are grown in situ using a highly concentrated perovskite colloidal solution in 2-methoxyethanol. Introducing methylammonium chloride enhances grain reorganization during in situ growth and fusing-confined processes, effectively reducing grain boundaries and surface defects. This allows for the preparation of quasi-monocrystalline thick junctions of large grains (>100 μm) with high crystallinity, uniform orientation, and vertical penetration across the film thickness. Additionally, the carrier mobility and lifetime of the thick junctions are significantly enhanced. The optimized MAPbI3 detectors demonstrate an X-ray sensitivity of 2.6 × 104 μC Gyair–1 cm–2 and an exceptionally low detection limit of 1 nGyair s–1. Furthermore, inspired by a honeycomb structure, these detectors realize X-ray imaging in 64 × 64 pixels through a pixelated separation design, effectively reducing the charge-sharing effect. This study offers valuable insights into the preparation of large-scale perovskite quasi-monocrystalline thick junctions for highly sensitive X-ray detection and imaging applications.
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