Solid-state D102 dye sensitized/poly(3-hexylthiophene) hybrid solar cells on flexible Ti substrate

Flexible solid-state dye sensitized solar cell is an important milestone for low-cost, large scale fabrication of dye-sensitized solar cells. Flexible solid-state dye-sensitized solar cell is fabricated for the first time on titanium substrates using D102 sensitizer and a sputtered platinum semi-transparent cathode. Devices are illuminated from the cathode side since titanium substrates are non-transparent. Due to rear-side illumination, significant proportion of radiation is absorbed and scattered by poly(3-hexylthiophene) and platinum, respectively. Limiting the amount of platinum and poly(3-hexylthiophene), up to a point, is found to enhance device efficiency. The amount of platinum and poly(3-hexylthiophene) is optimized on glass substrates before fabrication of flexible devices on titanium substrates. The rough surface of titanium substrates is smoothened until a mirror finish and the growth of a thin layer of native oxide enhanced the device efficiency. Under optimized conditions, an efficiency of 1.20% is obtained for devices fabricated on titanium foil substrates. The lower efficiency as compared to conventional devices is mainly due to light absorption/scattering from the poly(3-hexylthiophene) and platinum layers.