Enhanced glucose sensing performance of p-n Cu2O homojunction promoted by Cu(I)/Cu(III) redox process

Developing enzyme-free glucose sensors that rely on transitional metal oxides has become a tendency to satisfy the growing demands of glucose monitor. In this work, the photoactive Cu2O film has been prepared by electrochemical deposition for effective and selective detection of glucose. Characterizations including XRD, Raman spectrum, UV–vis reflectance spectrum, and electrochemical testing were performed. We found that the as-prepared Cu2O films were self-composed of p-n Cu2O homojunction structure with enhanced photocurrent response for PEC-type glucose sensing. Further investigation on p-n Cu2O indicates that the intrinsic charge recombination has been retarded, which paves the way to construct photoelectrochemical-type (PEC-type) glucose sensors. Benefitted from the properties of p-n Cu2O homojunction, high sensitive PEC-type glucose detection has been achieved at the dual-range of 1 μM to 10 μM and 20 μM to 11 mM. We attribute to our investigations can provide in-depth understanding on electric assist-redox and glucose catalytic processes for the detection of glucose, that may guide the fabrication of glucose sensors with high sensitivity and selectivity.