A photoelectrochemical sensor for ultrasensitive dopamine detection based on single-layer NanoMoS2 modified gold electrode

Photoactive material is a crucial factor which affects the sensitivity and selectivity of the photoelectrochemical (PEC) sensor. A simple PEC sensing platform was fabricated using nanoMoS2 modified gold electrode (nanoMoS2/GE) in this paper. Three kinds of nanoMoS2, single-layer nanoMoS2, multiple-layers nanoMoS2 and small-sized nanoMoS2, were used to modify the electrode. It was found that the single-layer nanoMoS2 showed utmost PEC response. The photocurrent of nanoMoS2/GE was drastically improved upon the addition of dopamine, which was attributed to the life improvement of the electron-hole pairs. Based on the enhanced photocurrent signal, a PEC methodology for ultrasensitive determination of dopamine has been developed, which showed linearly enhanced photocurrent by increasing the dopamine concentration from 1.0 × 10−11 M to 1.0 × 10−5 M with a detection limit of 2.3 × 10−12 M and the RSD was 3.9% at 2.0 × 10−10 M (n = 9) under optimal conditions. This method showed high sensitivity, simplicity and wide linearity range which opened up a new promising signal-on PEC platform for small molecule detection in bioanalysis.