Exploring a Layered Iodide Perovskite Crystal with Centimeter-Size for Extended Spectral Polarization-Sensitive Photodetection

Two-dimensional (2D) materials, in particular emerging 2D layered hybrid perovskites, have manifested excellent potential for polarization-sensitive photodetection recently due to their highly intrinsic anisotropy, characteristic quantum-well structure and intriguing semiconducting properties. However, most of the reported 2D hybrid perovskites still suffer from limited crystal dimensions or narrow spectral photoresponse to the polarized light. Herein, we have developed a new layered iodide perovskite (s-BA)2(MA)Pb2I7 (1, s-BA+ is sec-butylammonium and MA+ is methylammonium) through symmetry-reduction and halide remolding, which exhibits highly structural anisotropy and a narrow bandgap of 2.02 eV. Strikingly, centimeter-sized crystals with dimensions up to 19 × 19 × 3 mm3 can be obtained via temperature cooling method. Based on such large crystals, photodetectors were fabricated which manifest impressive response to polarized light with a large dichroism ratio of about 1.16, notable responsivity of 97.22 mA W−1 and considerable detectivity of 2.79 × 1011 Jones. This work offers a new candidate to the further exploration of highly anisotropic hybrid perovskites for extended spectral polarization-sensitive photodetection.