Chemical Sensors: Photoelectrochemical Sensors

Semiconductor electrode has been widely used in diverse fields especially becoming a hot topic for photoelectrochemical (PEC) sensing application. Derived from electrochemistry (EC) and stimulated by the historic energy crisis, PEC sensors have been used widely these years with both the potentiometric and the amperometric types. In the article, we will introduce the background, principle, basic set-up, sensing mechanisms and typical applications of the PEC sensors. Based on that, the working electrodes in the PEC system have been developed from bulk semiconductors to nanoscale semiconductors exhibiting higher spatial resolution and better sensing performance. Also, the most used hybrid heterojunctions to improve the performance of PEC sensors are presented together with their charge carriers transportation behaviors. Afterwards, the aspects needed to be improved and future perspective of the PEC sensor are also given.