ZnO@TiO2 Architectures for a High Efficiency Dye-Sensitized Solar Cell

• Nanoconic TiO2 particles are loaded on the surface of aligned ZnO NWs successfully by a liquid phase deposition method.
• ZnO@TiO2 architectures exhibit high efficiency of the DSSCs.

Instead of the spin coating step, an improved electrochemical process is reported in this paper to prepare ZnO seeded substrates and ZnO nanowires (ZnO NWs). Vertically aligned ZnO NWs are deposited electrochemically on the ZnO seeded substrates directly forming backbones for loading nanoconic TiO2 particles, and hence ZnO@TiO2 heterogeneous architectures are obtained. When used as photoanode materials of the dye-sensitized solar cells (DSSCs), ZnO@TiO2 architectures exhibit enhanced power conversion efficiency (PCE) of the DSSCs. Results of the solar cell testing show that addition of TiO2 shells to the ZnO NWs significantly increases short circuit current (from 2.6 to 4.7 mA cm−2), open circuit voltage (from 0.53 V to 0.77 V) and fill factor (from 0.30 to 0.59). The PCE jumped from 0.4% for bare ZnO NWs to 2.16% for ZnO@TiO2 architectures under 100 mW cm−2 of AM 1.5 G illumination.

Graphical AbstractA fast and improved electrochemical process was reported to fabricate ZnO@TiO2 heterogeneous architectures with enhanced power conversion efficiency (ƞ = 2.16%). This paper focuses on achieving high dye loading via binding noncorrosive TiO2 nanocones to the outermost layer, while retaining the excellent electron transport behavior of the ZnO-based internal layer.Figure optionsDownload as PowerPoint slide