Design And Photoelectric Properties Of Porphyrin Sensitizers For Increasing Absorption

Dye-sensitized solar cell (DSC) has been widely regarded as the promising alternative to conventional silicon-based solar cells due to its low cost, fabrication technique, widely available raw materials, fine variety in color and shape, and the stability in photovoltaic performances against light intensity fluctuation. Its theoretical energy conversion efficiency can reach 33%-36%. Presently, energy conversion efficiency of DSC has reached up to 13% with worldwide researches. Extensive efforts have been carried out on the further improvement of the energy conversion efficiency of DSC.Porphyrin sensitizers with D-A configuration give a world record efficiency 13%, which demonstrates the promising application of porphyrin dyes for DSC. Porphyrin dyes have been studied due to its strong ability of light harvesting and the easy-handling porphyrin rings. Porphyrin dyes have two characteristic absorption bands, namely, Soret band and Q band. The Soret band, located between 400 to 450 nm, has a high molar extinction coefficient to 105. The Q band is always located between 500 to 700 nm. Additionally, The width and intensity of Q band will be strengthened if molecular’s asymmetry and conjugacy increased. As a result the porphyrin sensitizers improved can almost utilize the whole visible light region.In order to increase sensitizer’s light absorption capacity in the near-infrared region. (1) For the IPCE of porphyrin sensitivers in the region of 500-600 nm relative lower, designed and synthesized cosensitizer HB, whose absorption maximum at ～500 nm. The gap in the IPCE spectrum of porphyrin sensitizer was filled and η=2.61% were improved by 26% relative to the device made of porphyrin alone. (2) In order for the light absorption region to red shift, tetrabenzoporphyrins with 34 π Electronics and good near-infrared spectral characteristics. Designed tetrabenzoporphyrin molecular structure and synthetic route, and have done a lot of preliminary work. However, normal decarboxylation conditions were far too harsh for intermediate 7, which caused this work could not be completed. At lsat Explored reduction of 2-ethyl group pyrrole derivative ethoxycarbonyl and used for synthesis porphyrin, the total yield was 3-5%.