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Shuttling Photoelectrochemical Electron Transport in Tricomponent CdS/rGO/TiO2 Nanocomposites

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journal contribution
posted on 10.10.2013 by Haihua Yang, Stephen V. Kershaw, Yu Wang, Xuezhong Gong, Sergii Kalytchuk, Andrey L. Rogach, Wey Yang Teoh
Composite photoelectrodes consisting of CdS sensitizer, reduced graphene oxide (rGO) transporter, and TiO2 acceptor were synthesized in a solvothermal synthesis. Under solvothermal conditions, the dimethyl sulfoxide (DMSO) solvent medium decomposed to form free sulfides, which facilitated the formation of CdS and, at the same time, which also reduced graphene oxide sheets by forming disulfide moieties. Compared to pure CdS and TiO2, coupling of these materials either as bi- or tricomponent composites (including rGO) allowed efficient interfacial charge separation and prolonged electron lifetimes. In particular, in the CdS/rGO/TiO2 tricomposite case, the rGO plays vital roles in alleviating trapped electrons at the heterojunction and serves as a platform for shuttling electrons between CdS and TiO2. Taking into account all of the structure-related charge-transport characteristics, including interfacial contacts, the highest quantum efficiency (incident photon-to-current efficiency, IPCE, at 460 nm = 12%) was achieved for the CdS/rGO/TiO2 tricomposite, and this was 6-fold that of CdS/TiO2.