Synthesis Of New π-conjugated Porphyrin And Dyes Applications In Dye-sensitized Solar Cells

Porphyrin compounds can be used in the dye-sensitized solar cell (DSSC)as pure organic dyes for the following reasons:(1) a good optical, thermal andchemical stability;(2) without expensive or harmful metal in these compounds;(3) higher molar absorptivity than the ruthenium-bipyridine complexes.Furthmore, porphyrin molecule is feasible to be designed. This makes itpossible to obtain dye sensitizers with better performance throughembellishing the porphyrin molecules by a variety of means.Through Vilsmeier-reaction with the2,2':5',2''-Terthiophene as rawmaterial, in which the electrophilic reagent was synthesized in the temperatureof nearby zero degrees Centigrade with POCl3as condensating agent andDMF as formylating agent, then the H in the position ofαof2,2':5',2''-Terthiophene was substituted by the electrophilic reagent, the5-formyl-2,2':5',2′′-terthiophene was obtained via basic hydrolysis (pH=8),ofwhich the higher purity quotient was obtained through silica flashchromatography with the productive rate of84.97%. It's structure was characterized and analyzed using FT-IR,UV-vis,1H NMR, and the meltingpoint and boiling point was measured and analyzed by DSC, which was inagreement with the literature.A series of new porphyrin compounds and their metal zinc complexeswere designed and synthesized by introduction of theπ-conjugated groupssuch as thiophene,2,2':5',2''-terthiophene, carboxyphenyl and hydroxyphenyl.The structure and properties of the porphyrin compounds andtheir metal zinc complexes were characterized by FTIR,1HNMR and UV-vis.The results showed that the metal complexes were no absorption peaks of N-Hin the FTIR spectra, and without chemical shifts in the high field in the spectraof1HNMR. In the UV-vis spectra of the porphyrin zinc complexes, theSoret absorption band was red shift and the intensity of the absorbanceenhanced, but the Q absorption band was blue shift and the numbers ofthe absorption band decreased. The thermal stability of porphyrin compoundsand their metal zinc complexes was studied by TGA, which showed that thethermal stability of the metal complexes was better than the correspondingporphyrin compounds.The synthetic porphyrin complexes were used in the DSSC as the dyesensitizer and the performance of the DSSC was tested. The results showedthat the TTTPPZn with the structure of "D-π-A" had a better performanceand higher photoelectric conversion efficiency than the other porphyrincompounds, but it was still lower than the performance of the DSSC with the synthetic N3dye. So how to design and embellish the porphyrin moleculesshould be further studied.