Transparent front contact optimization in dye sensitized solar cells: use of cadmium stannate and titanium oxide by sputtering

摘要

A reliable transparent front contact of cadmium stannate (CTO) and titanium oxide (TiO_2) entirely deposited by magnetron sputtering has been studied and applied to build standard dye-sensitized solar cell. CTO gives very high average optical transmittance (T_(avg) ≥ 90%) along with competitive sheet resistance (R_(sheet) ≤15 Ω/sq), while a very thin layer of TiO_2 (thickness ＜ 5 nm) acts as buffer layer to prevent charge recombination. The matched materials allow achievement of good performances of the cells, in terms of short circuit current and power conversion efficiency. UV-visible spectrophotometry, glancing incident X-rays diffraction and X-rays reflectivity techniques were used to characterize thin films before cell realization; sealed solar cells were tested under simulated solar irradiance at 1 Sun to determine functional properties.