Boron-induced metamorphosis of graphitic structures - a new form of mesoscopic carbon

Abstract

Summary: Several new allotropes of carbon have been discovered in recent decades with unique physical properties, enabling innovations in numerous applications from energy storage/conversion to water purification to drug delivery. The exceptional versatility of carbon begs the question, are there other carbon allotropes or mesoscale structures yet to be discovered? Herein, a unique mesoscopic tubular carbon is introduced, referred to as Boron Ortho-carborane Doped (BOD) Carbon, which is obtained by boron doping of the pseudo-graphite known as GUITAR (Graphite University of Idaho Tar). BOD-carbon exhibits a disordered nano-graphitic structure with basal atomic planes aligned with the tube axis. While GUITAR consists of overlapping downward curving structures, BOD-carbon consists of upward-curving hemispheres. The change in the growth direction characteristic of BOD-carbon as well as its two-stage growth from spherical to tubular, are attributed to B substitution of C and/or interstitial B, concomitant with a different strain state that modifies the energy in CC bonds as well as at the carbon-Si interface. This work demonstrates that previously unobserved forms of graphitic carbon can be obtained by manipulating strain in graphitic carbon at the atomic scale. BOD-carbon promises unique applications beyond the capabilities of the already known carbon nanotubes.

Keywords

• Graphitic
• Carbon
• GUITAR
• Boron
• Mesostructures