Fully printable perovskite solar cells with highly-conductive, low-temperature, perovskite-compatible carbon electrode

Abstract We obtain a novel kind of highly-conductive, low-temperature and perovskite-compatible carbon paste treated with the functional additives of titanium (IV) isopropoxide and acetic acid. The functional additives in the carbon paste can in si-tu generate newly complex polymeric Ti-O-Ti species acting as binder and plasticizer. It helps the electrical conductivity of carbon film increase to 1.13 × 104 S m−1, which corresponds to a sheet resistance of 4 Ω □−1 for a typical 20 μm film, superior to the transparent FTO/ITO electrode (15 Ω □−1). Then the carbon film is applied as the low-temperature carbon electrode into fully printable mesoscopic perovskite solar cells and a champion efficiency of 14.04% is achieved. Meanwhile, the series resistance of device based on low-temperature carbon electrode can be reduced from 21 to 13 Ω cm2, compared to device based on high temperature carbon electrode only. This low-temperature, low cost, highly-conductive carbon film shows promising application in the future module design of fully printable mesoscopic perovskite solar cells.