Highly Polarization‐Sensitive Solar‐Blind Ultraviolet Photodetection Based on 1D Rb₂CuCl₃ Microwires

Abstract Polarization‐sensitive solar‐blind ultraviolet (UV) photodetectors are essential in both civilian and military applications. 1D perovskites derivative Rb₂CuCl₃ holds promise for polarization‐sensitive solar‐blind UV photodetectors due to its wide direct bandgap, anisotropic crystal structure, and long carrier lifetime. However, no studies on the polarization properties of Rb₂CuCl₃ are reported. Here, the electronic structural anisotropy of Rb₂CuCl₃ is confirmed by calculating the partial charge density distribution in the ac‐plane and bc‐plane. Then, the Raman‐active modes and corresponding atomic vibration modes are explored within the bc‐plane through joint experimental and theoretical Raman spectroscopy. Besides, angle‐resolved Raman, photoluminescence, and absorption spectroscopy reveal the intriguing anisotropic photoelectric characteristics of Rb₂CuCl₃ microwires (MWs). By using single Rb₂CuCl₃ MW as the photoactive layer, a polarization‐sensitive solar‐blind UV photodetector is fabricated, showing high photoresponsivity of 78 mA W⁻¹ and photocurrent anisotropy ratio of ≈1.7 at 265 nm. Importantly, the proposed photodetectors without encapsulation exhibit excellent stability in ambient air, retaining the original photocurrent after two months, showcasing practical applicability. This study underscores the promise of Rb₂CuCl₃ for high‐performance polarization‐sensitive solar‐blind UV photodetectors, contributing valuable insights into its electronic structure, photoelectric properties, and practical applicability.