Optical anisotropy of one-dimensional perovskite C4N2H14PbI4 crystals

Optical anisotropy is essential for the polarization-sensitive optoelectronic devices. Recently, in-plane anisotropy is demonstrated in various 2D layered materials. It has been proved that organic-inorganic perovskites possess excellent optical properties; however, the anisotropy of organic-inorganic perovskites is rarely reported because of the in-plane isotropic structure. Here, we report a large optical anisotropy of one-dimensional organic lead iodine perovskites C4N2H14PbI4 crystals, including emission, excitation and reflection anisotropy. An emission linear dichroic ratio of 5.5 and an excitation linear dichroic ration of 7 are achieved respectively, which are much larger than the in-plane anisotropy of 2D layered materials. The large optical anisotropy can be ascribed to the anisotropic dipole moment in the unique 1D chain structure. In addition, the PL of the 1D C4N2H14PbI4 crystal is dominated by the broadband self-trapped exciton emission due to the quantum confinement effect and strong electron-phonon interaction. Our results advocate that 1D perovskites are promising in the application of broadband polarization-sensitive optoelectronic devices.