A photoelectrochemical sensor for detection of 17β-estradiol using high-response type II heterojunction: Implementation of visualization strategy

It's imperative to detect low levels of 17β-estradiol (E2) and facilitate its analysis. Here, a photoelectrochemical (PEC) sensor using Ag2S-sensitized BiOBr photoanode material was designed for high-sensitivity analysis of E2. The PEC sensing mechanism was discussed, and the dramatic enhancement of photocurrent was attributed to the superior photoelectric conversion performance of the BiOBr/Ag2S type II heterojunction. With a wide linear range of 0.001–100 nM and a detection limit of 0.18 pM, the constructed PEC sensor exhibited desirable detection performance. Meanwhile, the sensor represented remarkable specificity and stability which was successfully applied to estimate E2 contents in lake water, human serum and milk samples. Furthermore, to cast off the restriction of the workstation, Prussian blue was modified as a cathode in another region of the PEC sensing electrode in advance, and finally, a visualization device for E2 detection was structured. The visual detection could be performed with the naked eye or quantified with the help of average RGB (red-green-blue) values on the basis of the change in color intensity. This study provided a promising approach for the development of practical PEC sensors.