A novel strategy for the construction of photoelectrochemical sensors based on quantum dots and electron acceptor: The case of dopamine detection

Most of the current techniques for the photoelectrochemical detection based on the hole oxidation of the reductive substances (acting as electron donor) present in the electrolytes. In this paper, we report a new concept to construct photoelectrochemical sensors based on the interaction between photo-excited electrons of quantum dots (QDs) and electron acceptors. It was found that benzoquinone (BQ) could act as an efficient electron acceptor of the photo-excited CdS QDs, thus blocking the electron transfer of CdS to the indium tin oxide (ITO) electrode, leading to decreased photocurrent Based on this phenomenon, a novel photoelectrochemical sensor for dopamine (DA) was developed. DA can be oxidized under weakly alkaline (pH 9.0) solution or by electro-deposition in neutral (pH 7.0) solution to form poly-dopamine. Poly-dopamine has abundant benzoquinone (BQ) groups, which acted as electron acceptors of the conduction band electrons of the photo-excited CdS QDs, leading to decreased photocurrent of CdS QDs. The method could detect DA with highly selectivity and sensitivity. This photoelectrochemical strategy based on photo-induced electron transfer between the electron acceptor and QDs opened a new avenue for the design of novel photoelectrochemical sensors. (C) 2014 Elsevier B.V. All rights reserved.