In situ preparation of CdS nanoparticles imbedded in a polyelectrolyte multilayer for photocurrent generation

CdS nanoparticles (NPs) were prepared and imbedded in polyelectrolyte multilayers (PEMs) in situ and applied to the photocurrent generation. The PEM films of the poly(propylviologen)/poly(3,4-ethylenedioxythiophene)- poly(styrenesulfonate) were prepared using layer-by-layer deposition. The Br- ions of the viologen groups were exchanged with S2- ion by dipping the PEMs films in a Na2 S solution. Then, the films were dipped in a solution containing Cd2+ to give CdS NPs of less than 10 nm in size. The CdS NP-PEM films form an efficient acceptor-sensitizer dyad system, which showed a good photocurrent of 70 nA cm2 at 380 nm for a 3.5 bilayer sample.