ZnAgInS Quantum Dot-Decorated BiOI Heterostructure for Cathodic Photoelectrochemical Bioanalysis of Glucose Oxidase

A ZnAgInS quantum dot (QD)-decorated BiOI microsphere (BiOI-ZAIS) heterostructure was first proposed and successfully employed for sensitive cathodic photoelectrochemical (PEC) bioanalysis. Specifically, the designed BiOI-ZAIS composite displayed significantly enhanced cathodic photocurrent response compared with individual BiOI microspheres and ZAIS QDs due to its improved charge separation efficiency. Furthermore, the Z-scheme migration mechanism of photoinduced carriers for the BiOI-ZAIS heterostructure was proposed according to the experimental results and energy level analysis. Notably, the fabricated PEC glucose oxidase assay system based on the BiOI-ZAIS heterostructure exhibited satisfactory sensitivity and anti-interference capability with a wide linear range from 0.03 to 30 μg·mL–1 and a low detection limit of 0.023 μg·mL–1 due to the favorable cathodic photoelectric property of the BiOI-ZAIS composite and the specificity of the enzymatic reaction. Moreover, this research is hoped to inspire interest in the design and development of other high-efficiency and nontoxic Z-scheme heterostructures for elegant PEC bioanalysis.