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.