Near-Infrared Indocyanine Materials for Bioanalysis and Nano-TiO2Photoanodes of Solar Cell

Two near-infrared fluorescence N-p-carboxybenzyl indocyanines with the maxima fluorescence emission wavelengths of 565 nm and 641 nm in water, respectively, were synthesized by the ultrasonic method. Compared with those in water, the fluorescence intensity of the dyes became weaker in the solution of an alkali, alkaline-earth, or transition metal ion, except in Ag+or Zn2+; in the solution ofα-cyclodextrin orβ-cyclodextrin, the fluorescence intensity of them was increased, even under strong acidic condition. The indocyanines were converted into their succinimidyl active ester for conjugating with NH2groups of lysine or BSA. Porous nano-TiO2film with 68~75 nm thickness was prepared on ITO conductive glass from tetrabutyl titanate by sol-gel. FESEM showed that the diameter of the nano-TiO2particle was 30~50 nm and the pore size was 200~300 nm. The indocyanines with or without the presence of the alkali, alkaline-earth, transition metal ion, or cyclodextrin could make the nano-TiO2films sensitized, and the products could be used as anodes for dye-sensitized solar cells.