High performance metal sulfide counter electrodes for organic sulfide redox couple in dye-sensitized solar cells

Abstract

In order to reduce the fabrication cost and improve the power conversion efficiency (PCE) of the dye-sensitized solar cells (DSSCs), a class of metal sulfides nanoparticles containing PbS, Ag2S, CuS, CdS, and ZnS are synthesized to replace the expensive and unqualified Pt counter electrode towards the regeneration of the organic sulfide redox couple. The cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel polarization curve results prove that the prepared PbS, CuS, and Ag2S show high catalytic activities toward the organic redox couple. The PCE values of corresponding devices using the sulfide counter electrodes reach 6.49% (PbS), 6.11% (Ag2S), and 5.29% (CuS), much higher than the DSSCs using Pt counter electrode (3.86%).