Seed crystal layer-assisted growth of CsPbBr₃ perovskite film via electro-spray deposition for sensitive direct X-ray detection

Highly sensitive X-ray detectors play a critical role in various sectors, including medicine, crystallography, and national security. Semiconductor-based direct X-ray detectors have the potential to become the next generation of detectors due to their superior advantages compared to existing detectors. Notably, perovskite materials, renowned for their exceptional performance in the photovoltaic field, could be utilized in the development of novel X-ray detectors with high sensitivity and low detection limits. However, challenges remain in thick film deposition techniques such as inadequate film uniformity, elevated processing temperatures, and limited scalability. In this study, we present an improved E-spray process incorporating a seed crystal layer for achieving high-quality CsPbBr₃ thick film deposition. The incorporation of a seed crystal layer effectively mitigates the coffee-ring effect by depinning the triple-phase contact line of precursor solution droplets, while also promoting oriented growth of the thick CsPbBr₃ film. Furthermore, we demonstrate a direct X-ray detector with remarkable sensitivity (13561.56 μC Gyair⁻¹ cm⁻² at 5 V) and an impressively low detection limit (0.052 μGys⁻¹). We anticipate that these results will stimulate interest in this field and facilitate advancements in perovskite-based detector technology.