“Reinforced concrete”-like flexible transparent electrode for organic solar cells with high efficiency and mechanical robustness

Flexible transparent electrodes (FTEs) with robust mechanical stability are crucial for the industrial application of flexible organic solar cells (OSCs). However, their production remains challenging owing to the difficulty in balancing the conductivity, transmittance, and adhesion of FTEs to substrates. Herein, we present the so-called “reinforced concrete” strategy which fine-tunes the structure of silver nanowires (AgNWs)-based FTEs with polydopamine (PDA) possessing good adhesion properties and moderate reducibility. The PDA reduces Ag+ to form silver nanoparticles (AgNPs) which grow like “rivets” at the AgNW junction sites; PDA stabilizes the AgNW skeleton and improves the adhesion between the AgNWs and polyethylene ter-ephthalate (PET) substrate and interface layer. The obtained AgNW:PDA:AgNP FTE exhibits excellent optoelectronic properties and high mechanical stability. The resulting flexible OSCs exhibit 17.07% efficiency, high flexibility during 10,000 bending test cycles, and robust peeling stability. In addition, this “reinforced concrete”-like FTE provides great advantages for the production of large-area flexible OSCs, thereby paving a new way toward their commercial application.