Bulk Photovoltaic Effect in a Pair of Chiral–Polar Layered Perovskite-Type Lead Iodides Altered by Chirality of Organic Cations

The bulk photovoltaic effect (BPVE) is a promising optoelectronic phenomenon for generating a steady-state photocurrent without a bias voltage. Nevertheless, the simple and rational design of materials exhibiting the BPVE remains an important topic in the relevant fields. Here, we report the observation of the BPVE in a simple chiral-polar pair of layered perovskite-type lead iodides in the crystal space group of P1 (#1), which were synthesized by assembling R- and S-chiral organic cations, respectively. The sign of the zero-bias photocurrent is altered by the R/S-chirality of the assembled cations, which define the direction of electric polarization derived from the electric dipole moment of each chiral organic cation aligned in a crystal. The strategy of chirality control in a crystal is expected to be useful when searching for BPVE materials.