Three-dimensional flexible Au nanoparticles-decorated TiO2 nanotube arrays for photoelectrochemical biosensing

Abstract Controlling the charge transfer and thus enhancing the excitons’ lifetime are the key to the realization of efficient photoelectrochemical (PEC) devices. Moreover, fabrication of flexible and collapsible sensors can greatly facilitate the implementation of smart PEC sensing devices into practical applications. Herein, we sagely designed and successfully fabricated three-dimensional flexible Au nanoparticles-decorated TiO2 nanotube arrays (Au@TiO2) for the efficient PEC biosensing of glucose. The Schottky barrier derived from the Au@TiO2 heterostructure efficiently separates the charge carriers at the junction interfaces, thus greatly increasing the concentration and lifetime of holes left in the valence band of TiO2. The separated holes further evidently generate the active hydroxyl radicals, which can specifically recognize and oxidize glucose. As a result, Au@TiO2 exhibits excellent photoelectric activity and selectivity, far superior to TiO2 without decorated Au nanoparticles. In addition, such asymmetric Au@TiO2 system has been proved to feature the intrinsic flexibility nature, since its PEC biosensing performance is almost unaffected under indirect light irradiation and serious tensile strain.