S-induced Phase Change Forming In₂O₃/In₂S₃ Heterostructure for Photoelectrochemical Glucose Sensor

In the past several decades, Photoelectrochemical (PEC) sensing still remains a great challenge to design highly-efficient semiconductor photocatalysts via a facile method. It is of much importance to design and synthesize various novel nanostructured sensing materials for further improving the response performance. Herein, we present an In₂O₃/In₂S₃ heterostructure obtained by combining microwave assisted hydrothermal method with S-induced phase change, whose energy band and electronic structure could be adjusted by changing the S content. Combining theoretical calculation and spectroscopic techniques, the introduction of sulfur was proved to produce multifunctional interfaces, inducing the change of phase, oxygen vacancies and band gap, which accelerates the separation of photoexcited carriers and reduces their recombination, improving the electronic injection efficiency around the interface of In₂O₃/In₂S₃. As anticipated, an enhanced glucose response performance with a photocurrent of 0.6 mA cm⁻², a linear range of 0.1–1 mM and a detection limit as low as 14.5 μM has been achieved based on the In₂O₃/In₂S₃ heterostructure, which is significant superior over its pure In₂O₃ and S-doped In₂O₃ counterparts. This efficient interfacial strategy may open a new route to manipulate the electrical structure, and energy band structure regulation of sensing material to improve the performance of photoelectrodes for PEC.