Preparation of few-layer graphene with a low oxygen content and having a large area was attempted by the exfoliation of stage-1 K-THF-graphite intercalation compounds by adding alcohol solvents, where the effect of the alkyl-chain length of the added primary alcohol on the exfoliation behavior was investigated. Ultraviolet and visible absorption spectroscopy for the solvents after the exfoliation indicated that the longer the alkyl-chain length of the added alcohol, the more few-layer graphene was produced. Raman spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy revealed that exfoliation using 1-decanol produced few-layer graphene with the lowest oxygen content and a large area. The average thickness and area of the obtained few-layer graphene were 2.4 nm and 73 µm², respectively, which were almost the same as those （2.4 nm and 76 µm²） we reported for few-layer graphene prepared using an aldehyde such as 1-decanal.

Graphene nanoribbons are one-dimensional nanocarbon materials having semiconducting characteristics, which strongly depend on their width and edge structures. They have significant potential to be used in the broad fields of electronics, photonics, and energy harvesting. Bottom-up synthesis is greatly needed because of its ability to precisely control their width and edge structure to tune the bandgap. In this review, recent progress in bottom-up synthetic methods using on-surface and in liquid phase techniques, and their applications for electronic devices are introduced together with future prospects.

Electronic states of heteroatom-substituted carbon materials, such as boron/carbon (B/C) and boron/carbon/nitrogen (B/C/N) materials, have been studied experimentally through the X-ray absorption near-edge structures (XANES) together with the DV-Xα molecular orbital calculations. XANES study indicated that lowest unoccupied molecular orbital (LUMO) energies of B/C/N and B/C materials were lower than that of graphite. In these cases, B had a role of lowering the LUMO energies of B/C/N and B/C materials. Calcium (Ca) was intercalated into B/C materials to form intercalation compounds showing a first stage as well as a second stage structures through vapor phase reaction of Ca with the B/C materials solids, while Ca could not be easily intercalated into graphite through the same method. This is probably due to that the LUMO energies of B/C materials were lower than that of graphite and intercalated Ca having large ionization potential. The author concluded that there is a relation between the electronic structures and the donor-type intercalation behaviors of B/C and B/C/N materials.