Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Institution Author: search.filters.institutionAuthor.Sevim, Seçil

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  • Article
    Citation - WoS: 7
    Citation - Scopus: 7
    An Ultraviolet Photodetector With an Active Layer Composed of Solution Processed Polyfluorene:zn0.71cd0.29s Hybrid Nanomaterials
    (Elsevier Ltd., 2014) Sevim, Seçil; Memişoğlu, Görkem; Varlıklı, Canan; Doğan, Leyla Eral; Taşçıoğlu, Didem; Özçelik, Serdar
    An ultraviolet photodetector with an active layer of solution processed polymer:quantum dot hybrid is introduced. Poly[9,9-di-(2-ethylhexyl)-fluorenyl- 2,7-diyl] represents the polymer and Zn0.71Cd0.29S is the quantum dot used for the device. Photophysical studies showed that an electron transfer from the polymer to the ternary quantum dot is thermodynamically favored. Quenching experiments performed between the polymer and quantum dot indicates the formation of a non-fluorescent complex with an association constant of 4.6 × 104 M-1. The device structure of ITO/PEDOT:PSS/ADS231BE: 50 wt% Zn0.71Cd0.29S/Al yielded a photoresponsivity value of 324 mA/W at -4 V under 1 mW/cm2 illumination at 365 nm at room temperature and this value is further increased to 380 mA/W as a result of annealing at 75 °C.
  • Article
    Citation - WoS: 26
    Citation - Scopus: 27
    Developing a Facile 1 Method for Highly Luminescent Colloidal Cdsxse1_x Ternary Nanoalloys†
    (Royal Society of Chemistry, 2013) Ünlü, Caner; Ünal Tosun, Gülçin; Sevim, Seçil; Özçelik, Serdar
    We report a facile method to synthesize highly luminescent colloidal CdSxSe1 xternary nanoalloys. The synthesis is achieved exactly in one-step, one-pot and at low temperature, by applying the two-phase thermal approach. The optical and structural properties of the nanoalloys were characterized by various techniques. Photoluminescence of the nanoalloys is tunable from 435 to 545 nm by either the size or the composition of the nanoalloys. Highly luminescent nanoalloys having quantum yields up to 90% were prepared. The hydrodynamic size of the nanoalloys can be varied from 1.4 to 10.0 nm by the reaction time. DLS measurements showed that the size distribution of the nanoalloys is monodispersed. TEM images confirmed the size and the size distribution of the nanoalloys. The sulfur fraction in the nanoalloy composition, measured by XRD and verified by EDX, is modulated from 0.17 to 0.95 by increasing the amount of thiourea in the chalcogenide mixture. The sulfur-rich nanoalloys are formed when the initial mole ratio of the chalcogenide (S : Se) is equal or higher than eleven-fold. The gradient and homogeneous internal structures are revealed by analysis of the alloy composition as a function of the growth time. We propose that the two-phase approach, a non-injection technique, is a facile and versatile method to develop highly luminescent CdSxSe1 x nanoalloys without an inorganic coating layer.