Seeded growth of high-quality CsPbI3 single-crystalline fibers for photodetection

Although perovskite crystals exhibit defect tolerance, the presence of crystal defects may still compromise their photodetection performance. In this paper, we study the solution growth of high-quality δ-CsPbI 3 single-crystalline fibers (SCFs), and highlight the impact of crystal quality on the enhancement of the photodetector performances. To achieve high-quality δ-CsPbI 3 SCFs, a seeded growth of δ-CsPbI 3 SCFs is carried out using an optimized HI-DMF growth protocol. In this protocol, fiber seeds picked in HI aqueous solution are seeded to grow in DMF solution. As a result, high-quality flexible δ-CsPbI 3 SCFs with a large length-to-width ratio are obtained. The photodetector fabricated with the high-quality SCF in an Ag/CsPbI 3 /Ag architecture exhibits a low dark current, excellent device stability, a higher signal-to-noise ratio and a ninefold enhancement in photo-responsivity compared with the detector made using defective crystal. These findings establish a critical link between crystal perfection and advanced photodetector functionality, offering new avenues for high-performance X-ray detection technologies. Graphical abstract CsPbI 3 single-crystalline fibers prepared by seeded growth exhibit high crystal quality, excellent flexibility and enhanced photodetection performance.