Control of the size and photochemical properties of Q-CdS particles attached to the inner and/or outer surface of the lecithin vesicle bilayer membrane by the nature of its precursors

Abstract Cadmium sulfide nanoparticles have been generated in situ on the inner and/or outer surfaces of monolamellar lecithin vesicles. Chemical agents, strongly chelating or bounding the Cd 2+ cations, are shown to influence dramatically the size of CdS nanoparticles as well as their optical, luminescence and photochemical properties. The more stable is a Cd 2+ -containing complex created by these chelating agents, the smaller are the CdS particles formed. In case of CdCl 2 and Cd(NO 3 ) 2 as the CdS precursors inside the vesicles, a steady rise in the size of growing CdS nanoparticles is observed, while in case of K 2 [CdEDTA] the accumulation of mass of growing CdS occurs without a change in the nanoparticles size. The size of CdS particles and their initial growth rate depend also on pH of the vesicle suspension, modification of the lipid membrane, being, however, independent of the CdCl 2 concentration, if CdCl 2 is the CdS precursor. In the presence of a sacrificial electron donor (S 2− or EDTA), the bandgap irradiation of the lipid-vesicle-supported CdS particles yields charge separation and electron transfer to lipophilic cetylviologen bications, C 16 V 2+ , embedded into the lipid bilayer. The initial quantum yield of C 16 V ⋅+ formation depends on the topology of vesicular systems and CdS localization on the inner or outer surface of the lecithin membrane. Presence of EDTA anions enhances sufficiently the initial quantum yield of vectorial electron phototransfer from CdS nanoparticles to cetylviologen.