Monolithically integrated CIGS sub-modules fabricated on new-structured flexible substrates

A 15.0 % conversion efficiency sub-module with monolithically integrated structure has been achieved on the new-structured flexible metal substrate. Device parameters are as follows: open circuit voltage (V_oc) = 10.54 V, short circuit current density (J_sc) =33.39 mA/cm, fill factor (FF) =0.683 and aperture area = 70.4 cm. Our developed flexible substrates can satisfy both´ thermal stability over 500 °C and good electrical insulation. The substrates have Al₂O₃ insulating layer formed by aluminum anodization. Anodization process enables large size formation without pinholes and roll-to-roll manufacturing. Therefore, our substrates have low cost possibility. Also, our flexible substrates have a capability to offer lightweight and high conversion efficiency integrated CIGS. Our substrates will not only contribute to the flexible PV market expansion, but also partly replace the rigid PV due to the advantage of lightweight.