Circular‐Polarization‐Sensitive Organic Photodetectors with a Chiral Nanopatterned Electrode Inverse‐Designed by Genetic Algorithm

ABSTRACT A metal–dielectric–metal nanocavity with a chiral nanopatterned metal electrode provides an effective platform for circularly polarized photodetectors, which allows the chiral optical response and photon‐to‐charge conversion to be optimized with minimal mutual interference. We employ a genetic algorithm to inversely design the electrode pattern to maximize the chiral response while incorporating a vacuum‐deposited small‐molecule multilayer, which enables precise alignment of the photoactive layer with the helicity‐dependent field distribution. The optimization yields a non‐intuitive metal nanopattern that achieves a high dissymmetry factor ( = 1.32) of external quantum efficiency ( = 16.7%) at a target wavelength, outperforming a representative conventional chiral nanopattern. The fabricated device with the optimized electrode achieves = 0.67 and = 8.1% near the target wavelength, and simulations of the fabricated device geometry, accounting for curvature in the multilayer stack, confirm helicity‐dependent plasmonic field distributions consistent with those of the idealized flat‐layer device used in the optimization. These results demonstrate the effectiveness of our inverse design strategy and provide a framework for the development of high‐performance thin‐film chiral optoelectronic devices.