Transparent and flexible PEDOT:PSS electrodes passivated by thin IZTO film using plasma-damage free linear facing target sputtering for flexible organic solar cells

We have investigated the characteristics of transparent and flexible PEDOT:PSS electrodes passivated by thin InZnSnO (IZTO) film for flexible organic solar cells (FOSCs). Using damage-free linear facing target sputtering (LFTS), an IZTO passivation layer was deposited on the gravure printed PEDOT:PSS electrode without causing plasma damage. The thickness of the IZTO passivation layer was found to critically affect electrical and optical properties of the IZTO/PEDOT multilayer because the continuity and morphology of the thin IZTO passivation layer were greatly influenced by thickness. At optimized IZTO passivation thickness of 20 nm, the IZTO/PEDOT:PSS multilayer electrode exhibited decreased sheet resistance of 353.6 Ω/sq and optical transmittance of 83.09% without flexibility degradation. The FOSC with an optimized IZTO/PEDOT:PSS electrode showed better performances than the FOSC with PEDOT:PSS electrodes due to the effect of a stable IZTO passivation layer. This indicates that IZTO passivation on the PEDOT:PSS electrode using a LFTS is one of the key solutions for improving the properties and stability of flexible PEDOT:PSS electrodes for high performance FOSCs.