Zeolitic-imidazolate-framework (ZIF-8)/PEDOT:PSS composite counter electrode for low cost and efficient dye-sensitized solar cells

ZIF-8 polystyrenesulfonate-doped poly(3,4-ethylenedioxythiophene) (ZIF-8/PEDOT:PSS) is prepared and used as the alternative counter electrode (CE) for dye-sensitized solar cells (DSSCs) based on I-/I-3(-) and Co2+/Co3+ redox mediators. It is found that incorporation of ZIF-8 in PEDOT:PSS results in boosting the catalytic activity and charge transferability of the ZIF-8/PEDOT:PSS composite toward the reduction of I-3(-) and Co3+ redox mediators compared with pristine PEDOT:PSS. The assembled DSSCs based on the (3%) ZIF-8/PEDOT:PSS composite CE in iodide-based cells yield 7.02% photoelectric conversion efficiency (PCE) which is comparable to that of the conventional platinum CE (PCE = 7.24%) and better than that of the pristine PEDOT:PSS (PCE = 4.00%) CE. In addition, the (1%) ZIF-8/PEDOT:PSS CE shows a PCE of 6.84% for cobalt-based DSSCs which is comparable to that of Pt (PCE = 7.56%).