Electrochemical deposition of organic semiconductors on high surface area electrodes for solar cells

A new method for the deposition of organic semiconductors (OSC) on a conductive substrate is reported. The method is based on the electrochemical deposition of OSC ions that are electrochemically produced during the process. Using the new method, a thin layer of perylene bis(phenethylimide) (PPEI) was deposited on a nanoporous TiO₂ electrode. The PPEI layer has a wide spectrum throughout the visible range resembling the polycrystalline form of this OSC. The resulting high surface area TiO₂/PPEI electrode has the advantage of having high optical density although only a thin layer of the resistive PPEI is deposited. Using a liquid electrolyte as a quencher, it is shown that the new electrode can operate as a front electrode in a high surface area bilayer OSC solar cell. This is the first step toward the fabrication of a low resistance and thus efficient OSC solar cell.