1D/2D/0D Mixed-Dimensional TiO2/ZnO/Ag Core-Shell Nanowires for High-Performance UV-Vis Photoelectrochemical Photodetectors

One-dimensional (1D) TiO2 nanowires (NWs) have potential applications in photoelectrochemical (PEC) photodetectors due to their unique 1D geometries and optical and electrical properties. However, the wide bandgap and insufficient surface area of TiO2 NWs hinder their response spectra and responsivity. Constructing mixed-dimensional heterostructures may improve their PEC performance by controllably tuning the structure and properties of materials with different dimensionalities. In this strategy, mixed-dimensional TiO2/ZnO/ Ag core-shell NWs were prepared by employing 1D TiO2 NWs with exposed {001} facets, 2D ZnO nanosheets (NSs), and 0D Ag quantum dots (QDs). The mixed-dimensional NW-based PEC photodetector exhibited a high responsivity (R = 730 and 490 mA/W) and a fast response speed (tau r/tau d = 1.10/0.91 and 1.52/0.61 s), with a broad response from the ultraviolet (380 nm) to visible (420 nm) region. The localized surface plasmon resonance of the 0D Ag QDs and unique type-II band alignment of 1D TiO2 NWs/2D ZnO NSs enhanced the light absorption and also the generation and separation of photogenerated carriers. These combined effects greatly enhanced the photodetector's performance, showing that this approach can be used to fabricate mixed-dimensional heterostructures for high-performance optoelectronic devices.

Automated summary

Mixed-dimensional TiO2/ZnO/Ag core-shell nanowires were prepared to improve the performance of photoelectrochemical photodetectors. The resulting photodetector exhibited high responsivity, fast response speed, and a broad response from UV to visible region, attributed to the enhanced light absorption and carrier generation and separation caused by the Ag quantum dots and type-II band alignment of TiO2 NWs/ZnO nanosheets.