Quasi-solid-state optical logic devices based on redox polymer nanosheet assembly.

We report fabrication of a quasi-solid-state optical logic gate based on a polymer nanosheet photodiode. Two amphiphilic copolymers, p(DDA/Ru) and p(DDA/Fc), which respectively have a ruthenium dipyridyl complex and a ferrocene derivative as a redox molecule, are synthesized to produce redox polymer nanosheets. To construct polymer nanosheet photodiodes, two redox polymer nanosheets were assembled onto an indium-tinoxide (ITO) electrode in a tailor-made manner. The ITO electrode was connected with a counter electrode using an agarose gel electrolyte. The simple two-electrode system performs as a quasi-solid-state polymer nanosheet photodiode (QS-PNP). The photocurrent flow direction of QS-PNP can be controlled to be anodic or be cathodic by changing the deposition order of the redox polymer nanosheets. The anodic and cathodic QS-PNPs were applied to construct optical OR and XOR logic gates. The OR logic gate was fabricated by connecting the anodic and cathodic QS-PNP in a series; XOR logic was fabricated by connecting two anodic QS-PNPs in series. In optical logic gates, excitations of p(DDA/Ru) were used as input signals, and photocurrent was used as an output signal. These optical logic gates operate in a quasi-solid-state in a simple two-electrode configuration, which facilitates integration of the logic elements.