Enhancing the photosensitivity of C60 nanorod visible photodetectors by coupling with Cu2O nanocubes

Abstract

One-dimensional C₆₀ nanostructures with tunable bandgaps and a wide optical absorption range are considered as potential candidates for ultraviolet/visible photodetectors. Herein, we report a low-cost visible photodetector based on C₆₀ nanorods (NRs), which was synthesized using the liquid–liquid interfacial precipitation method. The experimental results demonstrate that the photosensitivity of C₆₀ NR-based visible photodetectors can be enhanced significantly by coupling with Cu₂O nanocubes (NCs, ∼20 nm in size). The photosensitivity of a photodetector based on the C₆₀ NR/Cu₂O NC is ∼72.5 and 40 fold higher after ratio optimization with 405 and 532 nm light illumination, respectively, which are 3.8 and 5.6 times correspondingly higher than those of pure C₆₀ NRs. Furthermore, the energy band structure of the C₆₀ NR/Cu₂O NC heterojunction was analyzed using cyclic voltammetry to illustrate the dramatically enhanced photosensitivity. The enhanced mechanism of photosensitivity is ascribed mainly to the fact that the formation of a p/n heterojunction in the C₆₀ NR/Cu₂O hybrid strengthens the separation of photo-induced electrons/holes at the interface.