Development of photoanodes for performance enhanced dye sensitized solar cells

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buir.advisorOkyay, Ali Kemal
dc.contributor.authorUlusoy, Türkan Gamze
dc.date.accessioned2016-04-28T06:12:03Z
dc.date.available2016-04-28T06:12:03Z
dc.date.copyright2015-08
dc.date.issued2015-08
dc.date.submitted01-09-2015
dc.descriptionCataloged from PDF version of thesis.en_US
dc.descriptionxviii, 84 leaves : charts.en_US
dc.descriptionThesis (M.S.): Bilkent University, Materials Science and Nanotechnology Program, İhsan Doğramacı Bilkent University, 2015.en_US
dc.description.abstractWith a raising demand for clean and renewable energy sources in recent decades, dye sensitized solar cell (DSSC), as an efficient and low-cost solar cell technology, have attracted considerable attention and several efforts have been directed for the optimization of all components of DSSCs including photoanode, sensitizer dye, hole transport layer and counter electrode. The objective of this thesis is to provide a better understanding on the function of photoanode in overall performance of DSSC device by highlighting problems and limitations and offering proper solutions to tackle these deficiencies. Based on this understanding, this thesis reports, fabrication, characterization and analysis of designed three different cells to boost device photovoltaic performance which includes: 1) angstrom thick ZnO-sheathed TiO2 nanowires as photoanodes, 2) multifunctional omnidirectional antireflective coating, 3) peptide nanofiber network templated ALD-grown TiO2 nanostructures as photoanodes in DSSC. Since photoanode-dye interface engineering is of utmost importance, the first of our proposals in this thesis relies on a systematic approach to understand the impact of atomic layer deposited (ALD) angstrom-thick ZnO sheath on hydrothermally grown TiO2 nanowires (NWs) core utilized as photoanodes in DSSC. The results show that this ultrathin layer will contribute at device efficiency enhancement almost three times via reducing recombination rate of injected electrons, enhancement in collection efficiency of electrons via reducing density of surface trap states without hampering injection efficiency and increased dye uptake on TiO2 nanowires’ surface which in turn leads to increased light absorption. On the other work, we also utilized multifunctional organically modified silica (ORMOSIL) as antireflection coating layer on DSSC to improve conversion efficiency of the device via reduction in the light reflection. ORMOSIL coated DSSC surfaces show a low-reflective omnidirectional response in a wide range of wavelengths (400-800 nm). At normal incidence (𝜃=0°), the short circuit current density (JSC) is improved to an amount of 23% as a result of ORMOSIL coating. In addition, JSC meets even higher amounts of enhancement where 84% increase is recorded at 𝜃=30°. Moreover, this coating exhibits superhydrophobicity representing a contact angle of 155º. Finally, we proposed and implemented, self-assembled peptide amphiphiles nanofiber 3D networks in order to obtain TiO2 nanotube structures as a template in DSSC. These self-assembled peptide amphiphiles are resistant to high temperature and more durable than other kinds of peptide amphiphiles. The advantage of this 3D fiber composed template is its high surface area and interconnected solid support providing an effective template for formation of TiO2 network using ALD. On the other hand, since ALD offers uniform and conformal coating of high aspect ratio features, it ensures an ideal thin film coating method on high surface area nano-template materials such as the peptide nanofiber templates proposed in this study.en_US
dc.description.provenanceSubmitted by Betül Özen (ozen@bilkent.edu.tr) on 2016-04-28T06:12:03Z No. of bitstreams: 1 türkan gamze ulusoy thesis FINAL 1 SEPTEMBER 2015.pdf: 3254323 bytes, checksum: 320485bdd335c714f6c5c7e89e682f46 (MD5)en
dc.description.provenanceMade available in DSpace on 2016-04-28T06:12:03Z (GMT). No. of bitstreams: 1 türkan gamze ulusoy thesis FINAL 1 SEPTEMBER 2015.pdf: 3254323 bytes, checksum: 320485bdd335c714f6c5c7e89e682f46 (MD5) Previous issue date: 2015-08en
dc.description.statementofresponsibilityby Türkan Gamze Ulusoy.en_US
dc.embargo.release2017-08-20
dc.format.extentxviii, 84 leaves : charts.en_US
dc.identifier.itemidB151166
dc.identifier.urihttp://hdl.handle.net/11693/29005
dc.language.isoEnglishen_US
dc.rightsinfo:eu-repo/semantics/openAccessen_US
dc.subjectPhotovoltaicsen_US
dc.subjectDye sensitized solar cells (DSSCs)en_US
dc.subjectInterface engineeringen_US
dc.subjectAtomic layer deposition (ALD)en_US
dc.subjectMetal-oxidesen_US
dc.subjectZinc oxideen_US
dc.subjectTitanium dioxideen_US
dc.subjectAntireflection coatingen_US
dc.subjectPeptide templateen_US
dc.subjectNanofiberen_US
dc.titleDevelopment of photoanodes for performance enhanced dye sensitized solar cellsen_US
dc.title.alternativeYüksek verimli boya uyarımlı güneş pilleri için fotoanot geliştirilmesien_US
dc.typeThesisen_US
thesis.degree.disciplineMaterials Science and Nanotechnology
thesis.degree.grantorBilkent University
thesis.degree.levelMaster's
thesis.degree.nameMS (Master of Science)

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