Novel nanocrystal-integrated LEDs utilizing radiative and nonradiative energy transfer for high-quality efficient light generation

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buir.advisorDemir, Hilmi Volkan
dc.contributor.authorNizamoğlu, Sedat
dc.date.accessioned2016-01-08T18:21:26Z
dc.date.available2016-01-08T18:21:26Z
dc.date.issued2011
dc.descriptionAnkara : The Department of Electrical and Electronics Engineering and the Institute of Engineering and Sciences of Bilkent University, 2011.en_US
dc.descriptionThesis (Ph. D.) -- Bilkent University, 2011.en_US
dc.descriptionIncludes bibliographical references leaves 200-216.en_US
dc.description.abstractTo combat environmental issues escalating with the increasing carbon footprint, combined with the energy problem of limited resources, innovating fundamentally new ways of raising energy efficiency and level of energy utilization is essential to our energy future. Today, to this end, achieving lighting efficiency is an important key because artificial lighting consumes about 19% of total energy generation around the globe. There is a large room for improving lighting efficacy for potential carbon emission cut. However, the scientific challenge is to reach simultaneously high-quality photometric performance. To address these problems, we proposed, developed and demonstrated a new class of color-conversion light emitting diodes (LEDs) integrated with nanophosphors of colloidal quantum dots. The favorable properties of these semiconductor nanocrystal quantum dots, including size-tuneable and narrow-band emission with high photostability, have provided us with the ability of achieving highquality, efficient lighting. Via using custom-design combinations of such nanocrystal emitters, we have shown that targeted white luminescence spectra can be generated with desired high photometric performance, which is important for obtaining application-specific white LEDs, e.g., for indoors lighting, street lighting, and LED-TV backlighting. Furthermore, dipole-dipole coupling capability of these semiconductor nanocrystals has allowed us to realize novel device designs based on Förster-type nonradiative energy transfer. By mastering exciton-exciton interactions in color-conversion LEDs, we have demonstrated enhanced color conversion via recycling of trapped excitons and white light generation based on nonradiative pumping of nanocrystal quantum dots for color conversion. This research work has led to successful demonstrators of semiconductor nanocrystal quantum dots that photometrically outperform conventional rareearth phosphor powders in terms of color rendering, luminous efficacy of optical radiation, color temperature and scotopic/photopic ratio for the first time.en_US
dc.description.provenanceMade available in DSpace on 2016-01-08T18:21:26Z (GMT). No. of bitstreams: 1 0006338.pdf: 6233162 bytes, checksum: 0b4a33a0009902b67051bb68e96bb48d (MD5)en
dc.description.statementofresponsibilityNizamoğlu, Sedaten_US
dc.format.extentxxvii, 216 leaves, illustrationsen_US
dc.identifier.urihttp://hdl.handle.net/11693/15615
dc.language.isoEnglishen_US
dc.rightsinfo:eu-repo/semantics/openAccessen_US
dc.subjectLight emitting diodesen_US
dc.subjectsolid state lightingen_US
dc.subjectnanocrystalsen_US
dc.subjectquantum dotsen_US
dc.subjectcolor conversionen_US
dc.subjectnonradiative energy transferen_US
dc.subjectexciton-exciton interactionsen_US
dc.subject.lccTK7871.89.L53 N59 2011en_US
dc.subject.lcshLight emitting diodes.en_US
dc.subject.lcshNanostructures.en_US
dc.subject.lcshEnergy transfer.en_US
dc.titleNovel nanocrystal-integrated LEDs utilizing radiative and nonradiative energy transfer for high-quality efficient light generationen_US
dc.typeThesisen_US
thesis.degree.disciplineElectrical and Electronic Engineering
thesis.degree.grantorBilkent University
thesis.degree.levelDoctoral
thesis.degree.namePh.D. (Doctor of Philosophy)

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