Preparation of a three-dimensional interpenetrating network of TiO2nanowires for large-area flexible dye-sensitized solar cells

Abstract

Platinum (Pt) and single-wall carbon nanotubes (SWCNTs) were sprayed onto Titanium (Ti) mesh to form a Pt–SWCNT/Ti counter electrode using a vacuum thermal decomposition method at a low temperature. A three-dimensional interpenetrating network of TiO₂ nanowires (3-D IPN TNWs) was successfully prepared on Ti foil through a facile hydrothermal approach. A TiO₂ colloid was coated on the 3-D IPN TNWs to form a large-area flexible anode using a doctor-scraping technique. The influences of the concentration of NaOH on the growth of 3-D IPN TNWs and on the photovoltaic performances of dye-sensitized solar cells (DSSCs) were investigated. Under an optimized condition, the power conversion efficiency of a large-area (100 cm²) flexible DSSC reached 6.43%, with a short-circuit current density of 6.83 mA cm⁻², an open circuit voltage of 0.724 V, and a fill factor of 0.715. Under irradiation with a natural light intensity of 55 mW cm⁻² outdoors, the efficiency of power conversion was increased by 10.29% compared with the flexible DSSC without 3-D IPN TNWs.