Preparation and Physicochemical Properties of Nanomaterial/Fullerene Composites

Abstract

Bismuthene, an exfoliated two-dimensional material obtained from bulk bismuth, has drawn significant attention because of its unique electronic properties. Few-layered bismuthene (FLBi) with an average thickness of 1.0 nm was synthesized by the ball mill and sonication method. The FLBi film was fabricated onto a semiconducting SnO2 electrode by electrophoretic deposition (SnO2/FLBi). In the flash-photolysis time-resolved microwave conductivity measurement, the SnO2/FLBi film showed a rise of conductivity upon photoexcitation, supporting the occurrence of the electron injection from the photoexcited FLBi to the conduction band of SnO2. The SnO2/FLBi on a transparent fluorine-doped tin oxide (FTO) electrode was used for photoelectrochemical devices. Photocurrents produced by the FTO/SnO2/FLBi electrode were larger than those produced by the FTO/SnO2 and FTO/FLBi electrodes because of the efficient electron injection. Moreover, FLBi was noncovalently functionalized with fullerene C60 in a mixed solvent of toluene and acetonitrile. Upon photoexcitation, the composite of FLBi and C60 exclusively led to the occurrence of photoinduced energy transfer from C60 to FLBi without generating the charge-separated state. These results give fundamental insights into the feasibility toward the construction of FLBi-based optoelectronic devices.Supramolecular composites consisting of fullerene C60 and carbon nanodiamond (ND) were prepared through spontaneous complexation of C60 aggregates onto the surface of ND aggregates in N-methylpyrrolidone. The resultant C60-ND composite was fabricated onto a nanostructured SnO2 electrode by an electrophoretic deposition method. Formation of the C60-ND composite was supported by dynamic light scattering and field-emission scanning electron microscopy. The C60-ND composite on the SnO2 electrode revealed high incident photon-to-current efficiencies in the visible region in comparison with the single component system of C60 or ND. The enhanced photocurrent generation of the C60-ND composite may originate from the photoinduced charge separation at the interface between C60 and ND. These results will give important insight into the design of all-nanocarbon optoelectronic devices.[1] T. Umeyama, Y. Okawada, T. Ohara, and H. Imahori, Chem. Asian J., 14, 4042-4047 (2019).[2] T. Umeyama, H. Xu, T. Ohara, Y. Tsutsui, S. Seki, H. Imahori, J. Phys. Chem. C, 125, 13954-13962 (2021).