Two-Dimensional Guanidine-Based Hybrid Perovskites with Strong Dichroism for Multiwavelength Polarization-Sensitive Detection

Two-dimensional (2D) organic–inorganic hybrid perovskites, benefiting from their natural anisotropy of quantum-well motifs and optical properties, have shown remarkable polarization-dependent responses superior to the 3D counterparts. Here, for the first time, multiwavelength polarization-sensitive detectors were fabricated by using single crystals of a guanidine-based 2D hybrid perovskite, (BA)₂(GA)Pb₂I₇ (where BA⁺ is n-butylammonium and GA⁺ is guanidium). Its unique 2D quantum-well structure results in strong crystallographic-dependence of optical absorption. Strikingly, our crystal-based photodetector exhibits a prominent photocurrent dichroic ratio (I_max/I_min) of ～2.2 at 520 nm, higher than the typical 2D inorganic materials (GeSe, ～1.09, PdSe₂, ～1.8). In addition, notable dichroic ratios of 1.29 and 1.23 at 405 nm and 637 nm are also created for the multiwavelength polarized-light detection. The prominent detecting performances, including low dark current (1.6×10^?11 A), considerable on/off ratio (～2×10³), high photodetectivity (～3.3×10¹¹ Jones) and responsivity (～12.01 mA W^?1), make (BA)₂(GA)Pb₂I₇ a promising candidate for polarized-light detection. This work sheds light on the rational engineering of new 2D hybrid perovskites for the high-performance optoelectronic device applications.