Synthesis and Self-Assembly of Flavin Derivatives around Single-Walled Carbon Nanotubes

Authors

Mehdi Mollahosseini, University of Connecticut - StorrsFollow

Date of Completion

1-3-2017

Embargo Period

1-1-2027

Keywords

Carbon Nanotubes, Self-Assembly, Synthesis, Charge transfer, Fullerene, Flavin

Major Advisor

Fotios Papadimitrakopoulos

Associate Advisor

Rajeswari Kasi

Associate Advisor

Faquir Jain

Field of Study

Chemistry

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

One of the greatest challenges with single-walled carbon nanotube (SWNT) photovoltaics and nanostructured devices is maintaining the nanotubes in their pristine state (i.e. devoid of aggregation and inhomogeneous doping) so that their unique spectroscopic and transport characteristics are preserved. To this effect, this thesis describes the synthesis and self-assembly of flavin derivatives (such as C₆₀-functionalized flavin (FC₆₀)), composed of functional moieties (i.e. PCBM) and the isoalloxazine group attached with various aliphatic spacers. Small amounts of FC₆₀ (up to 3 molar %) were shown to co-assembly with an organic soluble derivative of flavin (FC12) around SWNTs and impart effective dispersion and individualization. Thermal annealing was found necessary in order to perfect the isoalloxazine helix and expel groups that do not exhibit uracil-based, H-bonding recognition. The incorporation of 1% or higher FC₆₀ allows for an effective photoinduced charge transfer quenching of the encased SWNTs through the seamless helical encase. This is enabled via the direct π-π overlap between the graphene sidewalls, isoalloxazine helix and the C₆₀ cage, that facilitates SWNT exciton dissociation and electron transfer to the PCBM moiety. Such supramolecular nanotube architecture embarks on a new class of highly organized assemblies with profound importance for nanostructured devices.

One of the greatest challenges with single-walled carbon nanotube (SWNT) photovoltaics and nanostructured devices is maintaining the nanotubes in their pristine state (i.e. devoid of aggregation and inhomogeneous doping) so that their unique spectroscopic and transport characteristics are preserved. To this effect, this thesis describes the synthesis and self-assembly of flavin derivatives (such as C₆₀-functionalized flavin (FC₆₀)), composed of functional moieties (i.e. PCBM) and the isoalloxazine group attached with various aliphatic spacers. Small amounts of FC₆₀ (up to 3 molar %) were shown to co-assembly with an organic soluble derivative of flavin (FC12) around SWNTs and impart effective dispersion and individualization. Thermal annealing was found necessary in order to perfect the isoalloxazine helix and expel groups that do not exhibit uracil-based, H-bonding recognition. The incorporation of 1% or higher FC₆₀ allows for an effective photoinduced charge transfer quenching of the encased SWNTs through the seamless helical encase. This is enabled via the direct π-π overlap between the graphene sidewalls, isoalloxazine helix and the C₆₀ cage, that facilitates SWNT exciton dissociation and electron transfer to the PCBM moiety. Such supramolecular nanotube architecture embarks on a new class of highly organized assemblies with profound importance for nanostructured devices.

Recommended Citation

Mollahosseini, Mehdi, "Synthesis and Self-Assembly of Flavin Derivatives around Single-Walled Carbon Nanotubes" (2017). Doctoral Dissertations. 1418.
https://digitalcommons.lib.uconn.edu/dissertations/1418