Abstract: For a better design of quantum dots (QDs) based photoelectrochemical sensors, photoinduced electron transfer between CdS QDs and gold electrodes was studied. First, a theoretical study and mathematical model are given wherein several electron tunneling processes compete with each other to give a photocurrent under illumination. Second, simulations with different parameters were carried out. Finally, photocurrents from CdS QDs modified gold electrodes with dithiol groups were measured under different conditions. The results show that the amplitudes and directions of the photocurrents are affected by the applied potential, the light intensity, and the concentrations of oxidants and reducers. The experimental results were then compared with the simulation results and analyzed based on the model given. By comparing the simulation and experimental results the theoretical study and the mathematical model are shown to be accurate.

Key words: Quantum dot, Electron tunneling, Photoinduced electron transfer, Photocurrent, Photoelectrochemistry