Chemistry / Kimya

Permanent URI for this collectionhttps://hdl.handle.net/11147/4072

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Access Right: Embargoed AccessInstitution Author: search.filters.institutionAuthor.Özçelik, Serdar

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  • Article
    Citation - WoS: 3
    Citation - Scopus: 5
    Physically Unclonable Security Patterns Created by Electrospinning, and Authenticated by Two-Step Validation Method
    (IOP Publishing, 2022) Taşcıoğlu, Didem; Atçı, Arda; Sevim Ünlütürk, Seçil; Özçelik, Serdar
    Counterfeiting is a growing economic and social problem. For anticounterfeiting, random and inimitable droplet/fiber patterns were created by the electrospinning method as security tags that are detectable under UV light but invisible in daylight. To check the authenticity of the original security patterns created; images were collected with a simple smartphone microscope and a database of the recorded original patterns was created. The originality of the random patterns was checked by comparing them with the patterns recorded in the database. In addition, the spectral signature of the patterns in the droplet/fiber network was obtained with a simple and hand-held spectrometer. Thus, by reading the spectral signature from the pattern, the spectral information of the photoluminescent nanoparticles was verified and thus a second-step verification was established. In this way, anticounterfeiting technology that combines ink formula, unclonable security pattern creation and two-level verification is developed.
  • Article
    Citation - WoS: 3
    Citation - Scopus: 6
    Hybrid Photonic-Plasmonic Mode-Coupling Induced Enhancement of the Spontaneous Emission Rate of Cds/Cdse Quantum Emitters
    (Elsevier, 2022) Gökbulut, Belkıs; İnanç, Arda; Topçu, Gökhan; Özçelik, Serdar; Demir, Mustafa Muammer
    n this paper, a hybrid photonic-plasmonic resonator, which comprises an electrospun polymer fiber with a micrometer diameter and a core/shell nanostructure with a gold nanoparticle core, is constructed to investigate the dynamics of the coupled spontaneous emission of CdS/CdSe quantum dots (QDs). The gold nanoparticle core; covered with a silica shell, anchored with individual CdS/CdSe QDs, is placed inside a hollow cylindrical nanocavity formed on the surface of the microfiber to enable integration of the optical mode with the plasmonic effect, which is induced by the localized surface plasmons of the metal nanoparticle being present in the vicinity of the dipoles. The spontaneous emission rate of the QDs, coupled into the hybrid photonic-plasmonic mode, is measured to enhance by a factor of 23 via a time-resolved experimental technique. This result suggests that the regeneration of the optical mode-field inside the photonic-plasmonic resonator through the interaction of the dipoles with the localized surface plasmons of a metal nanoparticle strongly enhances the density of the electromagnetic states of the quantum emitters to facilitate an enhanced spontaneous emission within the host medium of the proposed polymer based-photonic structure.