Series Resistance Modulation for Large-Area Fully Printable Mesoscopic Perovskite Solar Cells

Perovskite solar cells (PSCs) have achieved a certified power conversion efficiency (PCE) of 25.5% and show potential for low-cost photovoltaic applications. One key of pushing PSCs into industrialization is enlarging their areas. However, the PCE of larger-area PSCs is dramatically limited by the undesired increase in series resistance ( R S ), which leads to obvious loss of fill factor (FF). Herein, R S in fully printable mesoscopic PSCs is modulated with a carbon electrode by optimizing the device geometry, preparing busbars to collect currents from electrodes and improving the conductivity of the back electrode. A rectangular device shape and tin busbars on conductive substrate effectively reduce the R S . Meanwhile, an additional hot-pressed highly conductive low-temperature carbon layer on the back carbon electrode also reduces the R S . An enhanced PCE of 13.99% for 1 cm 2 PSCs by R S modulation is obtained, whereas the control device exhibits a PCE of 7.74%. The PCE increase is due to the improvement of FF from 0.372 to 0.638 with reduced R S from 27.13 to 9.66 Ω cm 2 .