Ultrathin and efficient flexible polymer photovoltaic cells based on stable indium-free multilayer transparent electrodes

A method of fabricating ultrathin (similar to 25 mu m-thick) and efficient flexible polymer PV cells based on an indium-free transparent electrode with the structure of SiO2/WO3/Ag/WO3 (SWAW) has been developed. The SWAW flexible electrode exhibits excellent optical and electrical properties, with a high transmittance of similar to 90%, combined with a low sheet resistance of similar to 9 Omega sq(-1), and a work function of 5.16 eV. The flexible SWAW electrode is stable through 2000 bending cycles, has strong adhesion, and is thermally and environmentally stable. The performance of the polymer PV cells with the SWAW electrode are competitive with devices based on indium tin oxide (ITO) electrodes, which indicates that the SWAW electrode is a potential candidate for low-cost, light-weight and flexible transparent electrodes to replace ITO in efficient optoelectronic devices.