Enhanced photoresponses of polypyrrole on surface modified TiO2 with self-assembled monolayers

Photodevices comprising covalently grafted polypyrrole films on surface modified mesoporous TiO2 substrates via 3-(trimethoxysilyl) propyl methacrylate were fabricated and tested their performances with a counter electrode having a thin layer of gold. Significant photoresponses were observed with the addition of an ionic liquid, l-ethyl-3-methylimidazolium bis-trifluoromethylsulfonyl amide containing 0.2 M LiTf2N and painting a layer of graphite on the surface of PPY. The cell TiO2/PPY-C/Au cell delivered a short circuit current of ∼600 μA cm−2 with an open circuit voltage of ∼500 mV under the irradiation of 100 mW cm−2 (AM 1.5). The average corresponding fill factors and the efficiencies were 0.51 and ∼0.2%, respectively.