Synthesis And Application Of NovelβD-π-A Porphyrin Dyes For Dye-sensitized Solar Cells

Porphyrins as sensitizers have been a research fever in dye-sensitized solar cells.In this paper, we for the first time designed and synthesized three series of β D-π-Atype porphyrin dyes. The photochemical and electrochemical properties of all dyeswere discussed with UV-vis, fluorescence spectra and cyclic voltammetry. Absorptionproperties and the densities of dyes adsorbed on TiO2thin films were measured. Allnovel porphyrin dyes were also sensitized onto TiO2nanoparticulate films to serve asworking electrodes of DSSC devices for photovoltaic characterization.β D-π-A porphyrin dyes DPA11a-DPA11c in which the triphenylamine moietyacts as a donor, phenylacetylene as π bridge, and carboxyl as an anchoring group weresynthesized. The effect of triphenylamine moiety in these three dyes was studiedthrough the photochemical, electrochemical and photovoltaic comparison withreference dye R1without donor. The solar conversion efficiency of dye DPA11a-DPA11c and R1were2.52%,2.46%,2.43%and2.63%respectively. Dye R1withhigher photovoltaic performance than DPA11a-DPA11c mainly because of thenonplanar propeller type structure of triphenylamine which leads to a lower amount ofmolecular loading and the distortion of porphyrin ring.β D-π-A porphyrin dyes DPA12a-DPA12c in which the phenylamine moietyacts as a donor, phenylacetylene as π bridge, and carboxyl as an anchoring group weresynthesized. The effect of phenylamine moiety in these three dyes was studiedthrough the photochemical, electrochemical and photovoltaic comparison withreference dye R1without donor. The solar conversion efficiency of dye DPA12a-DPA12c and R1were2.17%,2.72%,2.69%and2.72%respectively. Dye R1withhigher photovoltaic performance than DPA12a-DPA12c mainly because of thedistortion of porphyrin ring and the aggregation of dye DPA12a-DPA12c whichnegatively influence the energy and electron transfer.β D-π-A porphyrin dyes DPA21a-DPA21c in which the phenylamine moietyacts as a donor, phenylacetylenes as π bridge, and two carboxyls as anchoring groupswere synthesized. The effect of phenylamine moiety in these three dyes was studiedthrough the photochemical, electrochemical and photovoltaic comparison withreference dye R2without donor. The solar conversion efficiency of dye DPA21a-DPA21c and R2were1.33%,2.27%,2.10%and3.65%respectively. Dye R2withhigher photovoltaic performance than DPA21a-DPA21c mainly because of the distortion of porphyrin ring and the aggregation of dye DPA21a-DPA21c whichnegatively influence the energy and electron transfer. The results further proved thatphenylamine moiety was the main reason for dye aggregation.Using the Sonogashira coupling reaction of β-bromoporphyrins as model, theapplication scope of Pd2(dba)3/AsPh3and Pd(PPh3)2Cl2/TBAF catalytic system wasexplored. A new family of β-pyrrole substituted porphyrins was also synthesized.