Bilayer polymer anode composed of poly(3,4-ethylene-dioxythiophene): polystyrenesulfonate (PEDOT:PSS) (PH500) and PEDOT:PSS (Baytron P VP Al 4083) was used to construct flexible polymer solar cells on plastic substrates polyethylene terephthalate (PET) with a device structure of PET/polymer anode/APFO-3:PCBM/LiF∕Al. The power conversion efficiency (PCE) of the indium tin oxide (ITO)-free solar cells achieved 2.2% under illumination of AM1.5 (100mWcm−2), which is 80% of the PCE of the reference cells with ITO on glass. The simplicity of preparing bilayer polymer anode and the comparable performance achieved in the flexible solar cells made the bilayer polymer anode an alternative to ITO for flexible solar cells produced by printing technology. Original article: APL: Organic Electronics and Photonics 1 (6), 212 (2008) We thank Professor Mats R. Andersson at Chalmers University of Technology for polymer supply. This work was financed by the Center of Organic Electronics at Linköping University, funded by the Strategic Research Foundation SSF. Yinhua Zhou acknowledges the scholarship from Chinese Scholarship Council (No. 2007U15021).