Nanoscale studies of CVD graphene and poly(3-hexylthiophene) thin films.

dc.contributor.advisorKelly, Kevin F.en_US
dc.contributor.committeeMemberPimpinelli, Albertoen_US
dc.contributor.committeeMemberNatelson, Douglasen_US
dc.contributor.committeeMemberAazhang, Behnaamen_US
dc.creatorRai, Chaitraen_US
dc.date.accessioned2014-10-08T18:08:41Zen_US
dc.date.available2015-05-01T05:01:02Zen_US
dc.date.created2014-05en_US
dc.date.issued2014-04-21en_US
dc.date.submittedMay 2014en_US
dc.date.updated2014-10-08T18:08:41Zen_US
dc.description.abstractTransparent solar cell systems have garnered a great deal of attention as possible alternatives to silicon-based solar cells. While conventional silicon-based solar cells absorb solar energy in limited frequency ranges, transparent solar cells absorb solar radiation in both the near infrared and ultraviolet regions of the electromagnetic spectrum. The challenge lies in improving the power conversion efficiency from the current 3.5%. It is therefore crucial to have a complete understanding of the electronic and structural properties of the component materials at the nanoscale to considerably improve their performance. For instance, controlling the morphology and electronic properties of the component acceptor and donor materials will have a direct impact on power conversion efficiencies. In this thesis, I present the use of scanning tunneling microscopy (STM) as a primary tool to analyze these materials with atomic scale resolution. The materials used in this work are monolayer graphene grown by chemical vapor deposition (CVD) and poly(3-hexylthiophene) (P3HT) thin films, which have great potential for use in transparent solar cells. This work outlines my findings in understanding and characterizing different substrate effects on graphene film growth, particularly useful for defect analysis and quality control. This thesis also presents analyses of the important role of pre-treatment of the Cu catalyst on the improvement in quality and continuity of graphene films. Further, this thesis also presents the morphological changes occurring in P3HT film crystallinity resulting from solvent mixing and propose an annealing free approach for efficient self-organization of chains via π-π interactions. I propose the use of two methods for quantifying the persistence length of the polymer chains: edge-detection based Hough transform and the worm-like chain model. By optimizing the graphene electrode and the polymer efficiency we hope to move closer to a carbon-based replacement for bulk semiconductor photovoltaics.en_US
dc.embargo.terms2015-05-01en_US
dc.format.mimetypeapplication/pdfen_US
dc.identifier.citationRai, Chaitra. "Nanoscale studies of CVD graphene and poly(3-hexylthiophene) thin films.." (2014) Diss., Rice University. <a href="https://hdl.handle.net/1911/77449">https://hdl.handle.net/1911/77449</a>.en_US
dc.identifier.urihttps://hdl.handle.net/1911/77449en_US
dc.language.isoengen_US
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.en_US
dc.subjectSTMen_US
dc.subjectGrapheneen_US
dc.subjectP3HTen_US
dc.titleNanoscale studies of CVD graphene and poly(3-hexylthiophene) thin films.en_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentElectrical and Computer Engineeringen_US
thesis.degree.disciplineEngineeringen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophyen_US
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