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

A reliable transparent front contact of cadmium stannate (CTO) and titanium oxide (TiO2) 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 Omega/sq), while a very thin layer of TiO2 (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. (C) 2013 Elsevier B.V. All rights reserved.