Molecular Engineering of Coaxial Donor-Acceptor Heterojunction by Coassembly of Two Different Hexabenzocoronenes: Graphitic Nanotubes with Enhanced Photoconducting Properties

摘要

We succeeded in the coassembly of two different hexa-peri-hexabenzocoronenes, one possessing an electron-accepting TNF unit (1) and the other unfunctionalized (2), affording graphitic nanotubes with varying acceptor concentrations. Photoconducting properties of the nanotubes are greatly enhanced by incorporating an appropriate amount of 2 in the nanotubes of 1. Advantageously, a rapid excitation energy migration in the graphitic layer of π-stacked HBC possibly occurs and contributes to the preservation of the high electron-transfer efficiency, to furnish the charge separation. Furthermore, a high concentration of TNF on the nanotube surface hardly promotes the charge recombination, thanks to the properly designed nanometer gap between the donor and acceptor layers. This achievement provides an important insight for the design of molecularly engineered optoelectronic materials with segregated donor—acceptor geometries.