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

Abstract

A method of fabricating ultrathin (∼25 μm-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 ∼90%, combined with a low sheet resistance of ∼9 Ω 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.