U-disk portable photoelectrochemical sensor based on bifunctional poly(o-phenylenediamine) for on-site detection of erythromycin

Developing portable sensing platform with robust signal intensity is essential for on-site detection. Here, a bifunctional poly(o-phenylenediamine) (PoPD)-involved portable photoelectrochemical (PEC) sensor is proposed for detecting erythromycin (Ery). Firstly, the PoPD polymer-semiconductor acts as a molecularly imprinted polymer for specific recognition of Ery and simultaneously serves as a key PEC-active component for constructing WSe2-x nanosheets/PoPD p–n heterojunction to enhance the PEC response. Secondly, a greatly simplified PEC sensing platform is developed utilizing a household flashlight and a lightweight U-disk workstation that connects to a smartphone via Bluetooth. The portable PEC sensor achieves high sensitivity with an excellent linear relationship in the range of 0.01–200 μM. It has a low detection limit of 3.9×10−3 μM (S/N = 3) and exhibits great stability, selectivity, and reproducibility. This work not only highlights the use of photoactive polymer semiconductors in the design of novel signal-enhancement PEC sensors, but also showcases an efficient portable sensing platform for potential on-site and real-time detection.