CdSe/TiO₂NTs Heterojunction-Based Nonenzymatic Photoelectrochemical Sensor for Glucose Detection

Compared with a single semiconductor, the heterojunction formed by two different semiconductors usually has higher light utilization and better photoelectric performance. By using stable TiO₂ nanotubes as the main subject, CdSe/TiO₂NTs heterojunctions were synthesized by a hydrothermal method. XRD, TEM, SEM, PL, UV-vis, and EIS were used to characterize the fabricated CdSe/TiO₂NTs. Under visible light irradiation, CdSe/TiO₂NTs heterojunctions exhibited a higher absorption intensity and lower degree of photogenerated carrier recombination than TiO₂. The electrons and holes were proven to be effectively separated in this heterojunction via theoretical calculation. Under CdSe/TiO₂NTs' optimal conditions, the glucose concentrations (10-90 μM) had a linear relationship with the photocurrent value, and the detection limit was 3.1 μM. Moreover, the CdSe/TiO₂NTs sensor exhibited good selectivity and stability. Based on the experimental data and theoretical calculations, its PEC sensing mechanism was also illuminated.