Ferrocenyl dithiocarbamate based d¹⁰ transition-metal complexes as potential co-sensitizers in dye-sensitized solar cells

Three new d¹⁰ transition-metal dithiocarbamates containing ferrocene, namely [M(FcCH₂EtOHdtc)₂] (M = Zn, Cd and Hg; dtc = dithiocarbamate) have been synthesized and characterized by elemental analyses, IR, ¹H, and ¹³C NMR spectroscopy, and X-ray crystallography. The coordination geometries around the zinc and mercury ions in the complexes are distorted tetrahedral and distorted linear, respectively. The distorted linear geometry around the mercury complex can be attributed to the presence of the bulky methylferrocenyl groups. These complexes have been used in dye-sensitized solar cells (DSSCs) as co-sensitizers and co-adsorbents. The assembly fabricated by using the zinc complex and N719 (Zn/N719) showed the best performance with an overall photon-to-current conversion efficiency (PCE) of 7.10±0.02%, which is an improvement of 23% in the cell performance compared with the DSSC fabricated by using N719 (PCE 5.76±0.04%) alone under identical conditions. Three new d¹⁰ transition-metal dithiocarbamates containing ferrocene have been synthesized and their application as co-sensitizers to the state-of-the-art dye N719 in dye-sensitized solar cells explored.