Optical Design of Transparent Thin Metal Electrodes to Enhance In‐Coupling and Trapping of Light in Flexible Polymer Solar Cells

Abstract
ITO‐free polymer solar cells with efficiencies as high as 6.6% and 5.8% are fabricated on glass and polyethylene naphthalate (PEN) by using TeO2 to enhance the in‐coupling of light in an Ag–Ag microcavity. These cells exhibit higher performance, selective microcavity resonance as a function of the thickness of TeO2, and better bending stability than flexible devices made with ITO.