Enhanced charge collection of AgNWs-based top electrode to realize high-performance, all-solution processed organic solar cells

All-solution processed organic solar cells are the ultimate aim of printable photovoltaics, but their electrical losses arising from poor contact of top electrodes greatly limit efficiency improvement. To solve the problem, a solution-processed hybrid top electrode was constructed using silver nanowires (AgNWs) as the skeleton and ZnO nanoparticles (ZnO-NPs) as the matrix. When constructing the skeleton, a spin-rinsing treatment was first used to reduce the amount of the residual insulating polyvinylpyrrolidone wrapped around the AgNWs to promote intimate contact among the AgNWs in the skeleton. Then, the ZnO-NPs matrix was deposited onto the AgNWs skeleton, bridging the AgNWs skeleton with the underlayer ZnO-NPs electron transporting layer (ETL). The underlayer ZnO-NPs ETL can also induce the growth of the ZnO-NPs matrix to minimize lattice mismatch, which creates additional transport channels from the ETL to the AgNWs skeleton for charge collection. As a result, the obtained electrode significantly enhances the electrical contact in the device, thus delivering record power conversion efficiencies of 16.04% and 14.54% for rigid and flexible all-solution processed OSCs, respectively.