Journal of Materials Science, Vol.50, No.24, 8064-8072, 2015
Enhancement of photocurrent generation from a series of hybrid nanocomposite self-assembled films of transition element-substituted tungstoborates/hemicyanine
A series of electrostatically self-assembled films have successfully been prepared by alternating adsorption of transition element-monosubstituted tungstoborate anions [BW11M(H2O)O-39](7-) (BW11M, M = Ni, Cu, Cd) and a bichromophore hemicyanine cation of (E)-1,1'-(hexane-1,6-diyl)bis(4-(4-(dimethylamino)styryl)pyridinium) (H-6), respectively. The UV-Visible spectra showed that the films were uniformly deposited and H-6 molecules formed J-aggregations in the films. The (BW11M/H-6) (n) films could generate stable cathodic photocurrents of 0.56-1.32 mu A/cm(2) as irradiated with white light (100 mW/cm(2), 730 nm > lambda > 325 nm) at zero bias voltage versus SCE, and the photocurrent action spectra indicated that the cathodic photocurrents were generated based on charge transfer excitation of the H-6 in the (BW11M/ H-6) (n) films. The composition and structure of polyoxometalate anion in the films have important influences on photocurrents. Moreover, the effects of layer number of (BW11M/H-6) (n) film, applied potentials, and electron acceptor in the electrolyte on photocurrent generation of the (BW11M/H-6) (n) films have been examined, and photoelectric mechanism is also discussed.