Tailoring crystallographic-orientation of one-dimensional CsCu2I3 single crystal wires towards enhanced solar-blind photodetection

The performance of photodetectors based on single crystalline CsCu2I3 for the solar-blind region needs optimization, particularly concerning the crystal orientation. Here, we prepared ultra-long high-quality CsCu2I3 microwires and nanowires with distinct preferred crystallographic orientations using two cost-efficient methods. Density functional theory (DFT) calculations along with spectrum characterization confirmed the feasibility of CsCu2I3 for short-wavelength photodetection. A solar-blind photodetector made from a single-crystalline (010)-oriented CsCu2I3 microwire exhibits exceptional performance under 265 nm irradiation at 0.58 mW cm−2, with a responsivity of 0.215 A W−1, a specific detectivity of 5.5 × 1011 Jones, and an on/off ratio of 260. Interestingly, while CsCu2I3 nanowire with a preferred (110) orientation show lower crystal quality in terms of trap density and carrier mobility, the solar-blind photodetector based on it outperforms the microwire-based photodetector. Under 265 nm irradiation at 0.57 mW cm−2, it achieves a responsivity of 0.806 A W−1, detectivity of 9.02 × 1011 Jones, and a high on/off ratio of 510. Moreover, microwire-based photodetector, when fabricated on a flexible substrate, exhibits little degradation of photoresponse even after 1000 bending cycles. These metrics position these photodetectors as top performers among lead-free perovskite-based detectors, demonstrating that engineering 1D CsCu2I3 single crystals with specific orientations can enhance advanced photo-electric devices. •(010)-oriented CsCu₂I₃ microwires were synthesized using an antisolvent titration method.•(110)-oriented CsCu₂I₃ nanowires were synthesized using a space-confined method.•The nanowires with higher trap density show better solar-blind photodetection performance.•Achieved a responsivity of 0.806 A/W, a detectivity of 9.02 × 10 ¹ ¹ Jones, and an on/off ratio of 510.•Engineering 1D CsCu2I3 single crystals with specific orientations enhances the solar-blind photodetection.