Biotemplated Synthesis of TiO₂-Coated Gold Nanowire for Perovskite Solar Cells

Fibrous nanomaterials have been widely employed toward the improvement of photovoltaic devices. Their light-trapping capabilities, owing to their unique structure, provide a direct pathway for carrier transport. This paper reports the improvement of perovskite solar cell (PSC) performance by a well-dispersed TiO₂-coated gold nanowire (GNW) in a TiO₂ cell layer. We used an artificially designed cage-shaped protein to synthesize a TiO₂-coated GNW in aqueous solution under atmospheric pressure. The artificially cage-shaped protein with gold-binding peptides and titanium-compound-biomineralizing peptides can bind GNWs and selectively deposit a thin TiO₂ layer on the gold surface. The TiO₂-coated GNW incorporated in the photoelectrodes of PSCs increased the external quantum efficiency within the range of 350-750 nm and decreased the internal resistance by 12%. The efficient collection of photogenerated electrons by the nanowires boosted the power conversion efficiency by 33% compared to a typical mesoporous-TiO₂-nanoparticle-only electrode.