Synthesis of Amorphous Er 3+ -Yb 3+ Co-doped TiO 2 and Its Application as a Scattering Layer for Dye-sensitized Solar Cells

, (ii) inefficient light absorption by dyes in the near infra-red region, (iii) sub-optimum photo-voltage output, (iv) resistance losses, (v) light intensity de-pendant recombination, (vi) and non-ideal diode dark currents among others. Efforts have led to maximum power con-version under full sunlight to about 10% for a cell with an ac-tive area of 0.25 cm