Infrared Spectroscopic Study of alpha-Cyano-4-hydroxycinnamic Acid on Nanocrystalline TiO2 Surfaces: Anchoring of Metal-Free Organic Dyes at Photoanodes in Dye-Sensitized Solar Cells

초록

Adsorption Structures of the self-assembled thin films of alpha-cyano-4-hydroxycinnamic acid (CHCA) anchoring on TiO2 surfaces have been studied by using temperatue-dependent diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy. From the presence of the strong v(COO-) band at similar to 1390 cm(-1) along with the disappearance of the OH hands, CFICAappeared to adsorb onto TiO2 Surfaces in the carboxylic acid group in the DRIFT spectra at room temperature. as a carboxylate form. The absence ofthe out-of-plane benzene ring modes of CHCA in the DRIFT spectra Suggests a rather vertical orientation of CHCA on TiO2. Above similar to 220 degrees C, CHCA seemed to start to thermally degrade oil TiO2 surfaces referring from the disappearance of most vibrational modes in the DRIFT spectra, whereas the v(C equivalent to N) bands were found to remain relatively conspicuous as the temperature increased even LIP to similar to 460 degrees C

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