Photo‐Assisted Barrier Effect for Improving the Sensing Performance to Copper Ions

Abstract Copper ions (Cu²⁺) pollution poses a serious threat to Marine ecology and fisheries, but the online detection is difficult due to seawater interference. Herein, photo‐assisted barrier effect is introduced into electrochemical detection as a driver to generate electrochemical response. The n–n junction barrier exhibits excellent adjusting effect on electrochemical response under photoexcitation and could effectively drive electrochemical response by Cu²⁺ adsorption. The prepared Ti/TiO₂/In₂O₃/Chitosan wire is used for direct Cu²⁺ detection, and the trace detection with the low detection limit (59.08 nm) is achieved. The strong interference of seawater is resisted effectively by using photo‐assisted barrier effect, and the good recovery rate (94.9–107.1%) in the actual seawater detection make it promising for practical applications. It is a new approach to develop electrochemical sensors by using photo‐assisted barrier effect to resist interference.