Photocatalysis through Excitation of Adsorbates. 3. Effect of Electron Acceptors on the Efficiency of Interfacial Charge Separation

Article abstract of DOI:10.1021/j100438a012

Charge separation in photoexcited rhodamine B-CdS-electron acceptor systems was investigated photochemically and photoelectrochemically, by using acceptors with different standard reduction potentials (E⁰_red.).The formal quantum efficiency (FQE) of N-deethylation of the dye after photoinduced electron injection into CdS (in photochemical suspension systems) and sensitized photocurrents flowing through a single-crystal CdS membrane separating the dye from an acceptor (in photoelectrochemical systems) were measured as a function of concentration of acceptors.Both FQE and sensitized photocurrents reflect the efficiency of charge separation between the dye and acceptors.Results indicate that charge separation occurs only in the presence of CdS and its efficiency rises as E⁰_red. of the acceptor is more positive.The effectiveness of the present systems for photoinduced charge separation is discussed.