Synthesis And Characterization Of Organic Push-Pull Photosensitizers

Organic push-pull photosensitized dyes may play a prominent role in the coming large-scale application of dye-sensitized solar cells due to their low-cost, abound resources and excellcent flexibility in molecular tailoring. In this thesis, we have designed and synthesized six novel organic push-pull photosensitized dyes. The structure and photoelectricial performance of the six sensitizers were investigated by NMR, UV-Vis spectroflurometer. Besides, photoelectrical performances of dye-sensitized solar cells were also scrutinized. The main contents are as follows:Four organic dyes coded S1, S2, S3, and S4 with different conjugated linkers such as 3,4-ethylenedioxythiophene (EDOT), bis-3,4-ethylenedioxythiophene (BiEDOT), PDOT, and BiPDOT have been prepared in combination with the the 2-ethylhexyloxy-substituted triphenylamine donor and the cyanoacrylic acid acceptor. S-series dyes possess suitable redox potentials and high molar extinction coefficient. The molar extinction coefficients of adsorption bands (527 nm,565 nm,520 nm and 550 nm) for sensitizer S1, S2, S3 and S4 are 38.95×103 M-1 cm-1,51.31×103 M-1 cm-1,36.65×103 M-1 cm-1, and 47.24×103 M-1 cm-1 respectively. Along with an acetonitrile/valeronitrile-based electrolyte, the power conversion efficiency (η) of a DSC with the organic sensitizer S1, S2, S3, and S4 under AM 1.5 G full sunlight is 6.46% and 3.56%,5.27% and 5.31%, respectively.Two organic dyes coded C304 and C305 with different electron-donor such as 4-ethoxy-N-(4-ethoxyphenyl)-N-phenylbenzenamine, and 4-dodecyloxy-N-(4-(dodecyloxy) phenyl)-N-phenylbenzenamine in combination with the 4,4-dihexyl-4H-cyclopenta [2,1-b:3,4-b']dithiophene (CPDT)Ï€-conjugated linkers and the cyanoacrylic acid acceptor. The molar extinction coefficients of adsorption bands (555 nm) for sensitizer C304 and C305 are 48.69×103 M-1 cm-1å'Œ48.94×103 M-1 cm-1, respectively, thus the length of ancillary ligands have little effect on the adsorption spectra of dye in chloroform solution. Along with AN/VN-based electrolyte, the power conversion efficiency (η) of a DSC with the organic sensitizer C304 and C305 under AM 1.5 G full sunlight is 7.87% and 7.74%, respectively.