Electron transport properties of fulgide-based photochromic switches

The transport properties of fulgide-based photochromic switches are investigated in the framework of density functional theory calculations. In our setup, light activated furyl fulgide molecules are coupled to nanoscopic metallic electrodes. The electrocyclization process under UV light converts the open-ring into a closed-ring conformation. Conversely, the reverse process takes place by visible light illumination. The switching properties are first analyzed in the linear bias regime revealing a high conductance ratio between the open and closed configurations. The robustness of the results is investigated by analyzing comparatively two compounds from the same family, namely furyl and thiophene fulgides. For both systems, at finite applied bias, one can establish three working regimes, which correspond in turn to a photochromic switch, a negative differential conductance element or to a logical inverter, pointing out the versatility of the considered fulgide-based devices.