Influence of Cr Thin Films on the Properties of Flexible CIGS Solar Cells on Steel Substrates

The material properties of molybdenum (Mo) and Mo/chromium (Cr) combined layers as back electrodes were compared with the electrical performance of copper indium gallium diselenide (CIGS)-based solar cells fabricated on steel foil. The addition of a Cr thin layer between the Mo films and stainless steel (STS) substrates increased the columnar grain size of Mo. These results could lead to enhancements in the solar cell efficiency for CIGS films evaporated on Mo/Cr, although the root mean square roughness increased from 187 to 251 nm compared with that of the Mo/STS sample.