Novel D-π-A dye sensitizers of polymeric metal complexes with phenylethyl or carbazole derivatives as donors for dye-sensitized solar cells: synthesis, characterization, and photovoltaic application

Four novel polymeric metal complexes containing D-pi-A type structures were synthesized, characterized and applied as dye sensitizers in dye-sensitized solar cells (DSSCs). The alkoxy benzene or carbazole (CZ) derivative acts as an electron donor (D), C=C acts as pi-bridge (pi) and the 8-hydroxyquinoline derivative complex acts as electron acceptor. Bipyridine derivative was ancillary ligand as well as providing anchoring group. FT-IR, gel permeation chromatography, thermogravimetric analyses, differential scanning calorimetry, UV-Vis absorption spectroscopy, Elemental analysis, cyclic voltammetry, J-V curves and input photon to converted current efficiency plots were introduced to investigate the four dyes. These dyes exhibit good thermal stability with 5 % weight loss at temperatures (T-d) of around 300 degrees C. For the DSSCs devices using dyes with CZ derivatives as electron D (P2, P4) exhibited higher power conversion efficiency (PCE) than that with alkoxy benzene (P1, P3). The DSSC based on P4 exhibited the highest PCE value of 2.42 % (J(sc) = 4.93 mA/cm(2), V-oc = 0.73 V, FF = 67.2 %) under AM 1.5G solar irradiation. This indicates a new way to design dye sensitizers for DSSCs.