Design and characterization of porphyrin sensitizers with a push-pull framework for highly efficient dye-sensitized solar cells

Novel porphyrin dyes YD14–YD17 with a push-pull framework were synthesized for dye-sensitized solar cells (DSSC); their spectral, electrochemical and photovoltaic properties were investigated. The absorption bands of these porphyrin dyes are broadened and red-shifted upon introduction of electron-donating groups (EDG) to the meso-positions via extension of π-conjugation. Electrochemical tests show that the first oxidation for these porphyrins occurs at a potential greater than that of the I−/I3− redox couple, and attachment of EDGs to the periphery of the porphyrin facilitates electron abstraction. The photovoltaic measurements show that YD14 and YD17 have a power conversion efficiency of ∼7%. Introduction of EDGs to various meso-positions is demonstrated to be achievable, and porphyrin dyes with appropriate EDGs are promising candidates for highly efficient DSSCs.