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dc.contributor.advisorDemir, Hilmi Volkan
dc.contributor.authorDede, Didem
dc.date.accessioned2018-08-10T13:09:31Z
dc.date.available2018-08-10T13:09:31Z
dc.date.copyright2018-08
dc.date.issued2018-08
dc.date.submitted2018-08-08
dc.identifier.urihttp://hdl.handle.net/11693/47736
dc.descriptionCataloged from PDF version of article.en_US
dc.descriptionThesis (Master's): Bilkent University, Department of Materials Science and Nanotechnology, İhsan Doğramacı Bilkent University, 2018.en_US
dc.descriptionIncludes bibliographical references (leaves 66-72).en_US
dc.description.abstractAs a new class of semiconductor nanocrystals, colloidal quantum wells (CQWs), also commonly known as nanoplatelets (NPLs), exhibit remarkable electronic and optical properties that will potentially nd a wide range of use from nanophotonics to optoelectronics. NPLs feature step-like absorption pro les and discrete emission spectra with giant oscillator strength resulting in high recombination rates. All these features make these atomically- at structures highly attractive for light-harvesting and -generating applications. In this thesis, to understand the size-tuned properties of their two-dimensional architecture, we conducted a systematic study on the core-only NPLs by using a set of 4 monolayer (ML) CdSe cores as our working model and carefully altered their aspect ratio while keeping their lateral area constant. In such a core-only NPL structure, electron and hole are both con ned in the core resulting in type-I electronic band alignment. By decreasing the width of these NPLs to a value comparable to or less than their exciton Bohr radius, we observe additional con nement e ects emerge. Subsequently, by growing CdSe1􀀀xTex alloyed crown around these starting 4 ML CdSe cores, we nd type-II electronic band alignment is obtained. Thanks to their spatially indirect excitons, these core crown NPLs show extraordinarily long radiative lifetimes. Moreover, with the increased absorption cross-section owing to their added crown, high-performance optical gain is achieved via their core/crown heterostructure. However, in this form, their usage is limited since they are unstable in solution forming gels and they exhibit strong tendency to form stacks in lms. To address this problem, here we proposed and developed a multi-crown architecture by additionally growing a CdS crown around the periphery of the type- II heterostructure, enabling excellent optical gain media with enhanced stability. The structural and optical characterizations of the synthesized multi-crown NPLs indicate that this complex architecture holds great promise for making devices in colloidal nanophotonics and optoelectronics.en_US
dc.description.statementofresponsibilityby Didem Dede.en_US
dc.format.extentxvii, 72 leaves : illustrations (some color), charts ; 30 cm.en_US
dc.language.isoEnglishen_US
dc.rightsinfo:eu-repo/semantics/openAccessen_US
dc.subjectColloidal Synthesisen_US
dc.subjectSemiconductor Nanocrystalsen_US
dc.subjectColloidal Quantum Wellsen_US
dc.subjectNanoplateletsen_US
dc.subjectOptical Gainen_US
dc.titleSynthesis and characterization of colloidal quantum wells: from simple size-tuned core to complex multi-crown structuresen_US
dc.title.alternativeKoloidal kuantum kuyularının sentezi ve karakterizasyonu: basit boyutları ayarlanabilir çekirdekliden karmaşık çoklu taçlı yapılaraen_US
dc.typeThesisen_US
dc.departmentGraduate Program in Materials Science and Nanotechnologyen_US
dc.publisherBilkent Universityen_US
dc.description.degreeM.S.en_US
dc.identifier.itemidB158767
dc.embargo.release2021-08-07


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