Optical Studies on Functionalized Graphene Systems

dc.contributor.advisorAjayan, Pulickel M.
dc.contributor.committeeMemberWeisman, R. Bruce
dc.contributor.committeeMemberYakobson, Boris I.
dc.contributor.committeeMemberMohite, Aditya D
dc.creatorGalande, Charudatta
dc.date.accessioned2014-08-26T21:23:37Z
dc.date.available2014-11-01T05:10:04Z
dc.date.created2014-05
dc.date.issued2014-05-05
dc.date.submittedMay 2014
dc.date.updated2014-08-26T21:23:37Z
dc.description.abstractGraphene, the ‘wonder material’, has received a lot of attention for its excellent electronic properties. However, the lack of a band gap severely limits its use, especially in optoelectronic applications. Therefore, opening a band gap in Graphene and controllably modifying its band structure has long been the holy grail in the physics of Graphene. Of these methods, chemical functionalization offers the most degrees of freedom in controllably modifying the band structure of Graphene. Graphene Oxide (GO), the most widely studied chemical derivative of Graphene exhibits a host of optical phenomena such as broadband tunable fluorescence, multiphoton-induced absorption and emission etc. and presents an excellent platform for studying the effects of chemical functionalization on the optical properties of Graphene. In the present work, we first deal with the issue of origin of fluorescence in GO. It is argued that the broadband emission arises due to localized states created on the Graphene surface due to presence of functional groups, and not due to quantum confinement. Next, we attempt to find which of the many functional groups in GO contribute the most to the emission intensity. We find that the carbonyl and epoxide functional groups contribute the most to fluorescence. Further, we find that irradiation with a laser causes an enhancement in the PL of multilayered GO sheets by increasing the density of carbonyl functional groups on the basal plane. This interesting phenomenon is proposed to occur due to a reaction between the oxygen-functionalized basal plane and water molecules trapped between the GO multilayers. We have also developed a method for synthesizing large-area Graphene by chemical vapor deposition (CVD) using liquid precursors. This opens up a host of new possibilities for substitutional doping of Graphene by using liquid precursors containing the dopant atoms.
dc.embargo.terms2014-11-01
dc.format.mimetypeapplication/pdf
dc.identifier.citationGalande, Charudatta. "Optical Studies on Functionalized Graphene Systems." (2014) Diss., Rice University. <a href="https://hdl.handle.net/1911/76726">https://hdl.handle.net/1911/76726</a>.
dc.identifier.urihttps://hdl.handle.net/1911/76726
dc.language.isoeng
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.
dc.subjectGraphene
dc.subjectGraphene oxide
dc.subjectOptoelectronics
dc.subjectGraphene Band Gap
dc.subjectGraphene Oxide Fluorescence
dc.titleOptical Studies on Functionalized Graphene Systems
dc.typeThesis
dc.type.materialText
thesis.degree.departmentMechanical Engineering and Materials Science
thesis.degree.disciplineEngineering
thesis.degree.grantorRice University
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy
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