The research of employing polyoxometalates as pure-inorganic electron-transfer mediators on dye-sensitized solar cells

Abstract Two Keggin-type polyoxometalates [K 6 Co II W 12 O 40 (denoted as {Co II W 12 }) and K 5 Co III W 12 O 40 (denoted as {Co III W 12 })] were firstly employed as the redox couple in dye-sensitized solar cells. Photocurrent density–photovoltage curves, cyclic voltammetry curves, photocurrent action spectra and UV–vis spectra demonstrated that {Co II W 12 } and {Co III W 12 } displayed weak absorption in the visible light region, potential matching with dye and TiO 2 conducting band, and significant conversion efficiency.