Toward Highly Efficient Large-Area ITO-Free Organic Solar Cells with a Conductance-Gradient Transparent Electrode

Highly efficient large-area organic solar cells (OSCs) with power conversion efficiency up to 7.09%, and device area of 4 cm(2) are demonstrated on flexible substrates. A conductance-or thickness-gradient ultra-thin Ag-based transparent electrode is developed to better balance the light trapping and energy loss, owing to the inhomogeneous energy-loss density on the large OSC sheet.