UV/VIS spectral properties of novel natural products from Turkish lichens

UV/VIS spectral characteristics of three new biologically active natural products, isolated from Turkish lichens, have been investigated in solvents of various polarity and proton donating ability. The effect of the solvent on spectral characteristics has been estimated. Quantum chemical calculations with the optimization of molecular geometry were done with the full-valent semiempirical methods AM1 and PM3 for conformational analysis and in order to discuss the charge distributions and dipole moments in the ground and in the excited states

Synthesis and spectroscopic properties of a novel perylenediimide derivative

A novel symmetric 3,4,9,10-perylenetetracarboxylic acid derivative (PDI1) dye based on thiophene donor group was synthesized and characterized by FT-IR and 1H NMR. Cyclic Voltammetry analysis is performed to determine the energy levels of the perylene derivative. Optical characteristics were determined by visible absorption and fluorescence emission spectra. Spectral behavior and fluorescence quantum yield of PDI1 have been measured in different solvents. The dye exhibits high fluorescence quantum yield ( Φf: 0.94-0.99). But the quantum yield PDI1 is very low in the n-butanol solution ( Φf: 0.12). The photophysical properties have important implications for use in a variety of electroactive and photovoltaic applications. A photovoltaic device was fabricated with PDI1 as transporting material. The conversion efficiency for DSSC sensitized by PDI1 is 0.0065%. PDI1 exhibits electrochromic behavior by switching between neutral (red) and oxidized (blue) states. Electron transfer capacity of PDI to the TiO2 was investigated by incorporation of dye as sensitizer in dye sensitized solar cell (DSSC). Soluble dye molecules are very important to prepare dye sensitized solar cell. Solubility was increased with thiophene group