Ti3C2 MXene quantum dots/TiO2 inverse opal heterojunction electrode platform for superior photoelectrochemical biosensing

Due to the ultrathin structure, functional groups and excellent physical-chemical properties, Two-dimensional (2D) MXenes shows great potential for biomedical applications. Here, we prepared TiO2 inverse opal photonic crystals (IOPCs)/Ti3C2 quantum dots (QDs) composite film through the self-assembly method. Because of the widen absorption band of Ti3C2 QDs, TiO2 IOPCs/Ti3C2 composite film could have photocurrent effect from 280 to 900 nm, and the internal power conversion efficiency could reach to 26% at 350 nm. Owing to favourable energy levels, Ti3C2 QDs were formed the Type-II Heterojunction with TiO2, thus enabling directional transport charge for efficient charge separation. The Type-II Heterojunction photoelectrochemical (PEC) sensor consisting of TiO2/Ti3C2/Nafion electrode exhibited high stability, sensitivity, and selectivity for the detection of glutathione in buffered solution and cell extracts. Thus, the TiO2/Ti3C2/Nafion composite film provides a promising green electrode for sensitive PEC detection, which could realize some potential applications for disease early precaution and diagnose.