The Studies of Fullerenes and Metallofullerenes in Geometry, Electron Transfer, Chromatography and Characterization

Since their discovery, fullerenes and metallofullerenes have been investigated regarding their structures, synthesis, isolations, and applications. The highly symmetric structures of fullerenes and metallofullerenes lead to extraordinary physical properties, such as electron transfers, and attract major attention from the science community. It has been well established that the stabilities of fullerenes and metallofullerenes can be estimated by recognizing structural patterns. Recently, we developed a generalized spiral program and additional codes and believe they are useful for fullerene/metallofullerene researchers. The higher fullerenes, those with more than 90 carbon atoms, also follow certain structural patterns. In our studies, we have shown that the higher fullerenes with tubular structures are stable in thermodynamics and can survive the aminopropanol reaction, but other spherical fullerenes cannot. For the past three decades, great efforts have been devoted to applying fullerenes and metallofullerenes as electronic materials. In our studies, we find the ground state electron transfer properties endow metallofullerenes as an ideal material for perovskite solar cells to enhance the stabilities. It has been shown in our investigations that common metallofullerenes, such as Sc3N@C80, are capable to be as the electron transfer layers in perovskite solar cells, and the test demonstrates that our novel perovskite solar cells may achieve high stability and high efficiency. The electron transfer abilities of metallofullerenes are studied with the M2@C79N since electron densities located in between the two metal atoms convert between a single electron bond and a double electron bond. The huge spherical electron delocalized structures of fullerenes and metallofullerenes lead to strong interactions with other delocalized systems, such as graphene. Previous studies have shown that graphene has a unique ability in molecular adsorptions. However, the graphene surface is not always flat and the rippled areas have effects on the packing styles. Therefore, we examined the behavior of fullerenes on the rippled graphene surface and then compared with another flat molecule, PTCDA. The results show that the effect of rippled areas varies due to molecular structures. This study gives instructions for electronic device manufacturing using graphene and fullerenes. In our studies, polarizability is a key factor of fullerenes and metallofullerenes. It has been shown that the chromatographic retention behavior has a strong relationship with the average polarizability of a molecule. Based on the experimental data, we built a model for the prediction of chromatographic retention times using computational polarizabilities. After that, we validated the model by two series of chromatographic data. The characterization of carbon-based materials has been long investigated. In the last chapter, we introduce a dynamic nuclear polarization-based method to characterize the structures of chars and studied the adsorption of oxygen on the activated radical sites. Overall, the dissertation reports my Ph. D. studies in the areas including theoretical studies of fullerene geometries, chromatographic models, applications and also experimental studies of the applications of fullerenes/metallofullerenes and characterization.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Chemistry

Department dc:contributor.department

Chemistry

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2019

Author dc:creator

• Liu, Xiaoyang

Chair dc:contributor.committeechair

• Dorn, Harry C.

Committee members dc:contributor.committeemember

• LaConte, Stephen M.
• Valeyev, Eduard Faritovich
• Lin, Feng
• Gibson, Harry W.

• fullerene
• metallofullerene
• geometry
• perovskite solar cell
• electron transfer
• chromatography
• dynamic nuclear polarization

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:21773

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/102264