Highly efficient 1 μm thick CdTe solar cells with textured TCOs

Thickness reduction of CdTe absorption layer down to 1 μm has been achieved by controlling the temperature profile used during the close-spaced sublimation (CSS) growth. Transparent conducting oxides, such as indium tin oxide (ITO) and textured fluorine doped tin oxide (SnO2:F) films have been investigated as transparent electrodes for such 1-μm-thick CdTe absorption layers to increase the incident light confinement and thus to achieve higher conversion efficiency. The contribution in solar cell performance has been found in the case of textured TCOs with optimum haze ratio (roughness). Conversion efficiencies of 10.6% (Voc: 0.75 V, Jsc: 22.02 mA/cm2, FF: 0.64, area: 1 cm2) and 11.2% (Voc: 0.78 V, Jsc: 22.6 mA/cm2, FF: 0.63) have been achieved for only 0.6-μm-thick CdTe absorption layers with SnO2:F-TCO of 11% and 3% of haze ratios, respectively.