Facile non-pressurized synthesis of nanowire-constructed hierarchical TiO₂ nanomaterials with improved dye sensitized solar cell performance

Nanowire-constructed hierarchical TiO₂ nanomaterials (HTN) are prepared by a facile non-hydrothermal method at atmospheric pressure. The product is characterized in detail using powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy and UV–Vis spectrophotometer. The synthesized TiO₂ hierarchical nanomaterials consist of nanowires of 15 nm in diameter, it possesses a high surface area of 144.65 m²/g, and demonstrate an excellent dye absorption ability (155.55 nmol/cm²), which is 2.7 times more than that of the Degussa P25. Corresponding photovoltaic performance of dye-sensitized solar cells (DSSCs) fabricated from HTN is also investigated. It exhibits an overall light-to-electricity conversion efficiency of 8.9% accompanying a short-circuit current density of 20.43 mA/cm², an open-circuit voltage of 720 mV and fill factor of 0.61, which is much higher than that of P25 (5.5%). The significant enhancement of short-circuit current density and power conversion efficiency of HTN can be attributed to its larger dye loading amount, better charge transportation ability and excellent light scattering ability.