ELECTROCHEMICAL AND PHOTOELECTROCHEMICAL PROPERTIES OF MONOAZA-15-CROWN ETHER-LINKED CYANINE DYES - PHOTOSENSITIZATION OF NANOCRYSTALLINE SNO2 FILMS

Photophysical, electrochemical, and photosensitization properties of n ewly synthesized crown ether derivatives of cyanine dyes have been inv estigated. These dyes exhibit strong absorption in the visible (450-55 0 nm) range with a solvent-dependent fluorescence quantum yield rangin g from 0.006 to 0.11 and adsorb strongly on SnO2 nanocrystallites. The singlet excited state is readily quenched when adsorbed on SnO2 nanoc rystallites as a result of a charge injection process. The photosensit ization properties of these cyanine dyes in extending the photorespons e of SnO2 semiconductor have been investigated by probing the dependen ce of photocurrent and photovoltage on the wavelength and intensity of excitation. A maximum photon to photocurrent conversion efficiency of similar to 1% has been observed.