Porphyrin Cosensitization for a Photovoltaic Efficiency of 11.5%: A Record for Non-Ruthenium Solar Cells Based on Iodine Electrolyte

Abstract

Dye-sensitized solar cells (DSSCs) are promising for utilizing solar energy. To achieve high efficiencies, it is vital to synergistically improve the photocurrent (<i>J</i>_sc) and the photovoltage (<i>V</i>_oc). In this respect, conjugation framework extension and cosensitization are effective for improving the absorption and the <i>J</i>_sc, which, however, is usually accompanied by undesirably decreased <i>V</i>_oc. Herein, based on a rationally optimized porphyrin dye, we develop a targeted coadsorption/cosensitization approach for systematically improving the <i>V</i>_oc from 645 to 727, 746, and 760 mV, with synergistical <i>J</i>_sc enhancement from 18.83 to 20.33 mA cm^–2. Thus, the efficiency has been dramatically enhanced to 11.5%, which keeps the record for nonruthenium DSSCs using the I₂/I₃^– electrolyte. These results compose an alternative approach for developing highly efficient DSSCs with relatively high <i>V</i>_oc using traditional iodine electrolyte