Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Citation - WoS: 1Citation - Scopus: 1Tailoring Quantum Dot Shell Thickness and Polyethylenimine Interlayers for Optimization of Inverted Quantum Dot Light-Emitting Diodes(MDPI, 2024-07-11) Yazici, Ahmet F.; Ocal, Sema Karabel; Bicer, Aysenur; Serin, Ramis B.; Kacar, Rifat; Ucar, Esin; Mutlugun, EvrenQuantum dot light-emitting diodes (QLEDs) hold great promise for next-generation display applications owing to their exceptional optical properties and versatile tunability. In this study, we investigate the effects of quantum dot (QD) shell thickness, polyethylenimine (PEI) concentration, and PEI layer position on the performance of inverted QLED devices. Two types of alloyed-core/shell QDs with varying shell thicknesses were synthesized using a one-pot method with mean particle sizes of 8.0 +/- 0.9 nm and 10.3 +/- 1.3 nm for thin- and thick-shelled QDs, respectively. Thick-shelled QDs exhibited a higher photoluminescence quantum yield (PLQY) and a narrower emission linewidth compared to their thin-shelled counterparts. Next, QLEDs employing these QDs were fabricated. The incorporation of PEI layers on either side of the QD emissive layer significantly enhanced device performance. Using PEI on the hole transport side resulted in greater improvement than on the electron injection side. Sandwiching the QD layer between two PEI layers led to the best performance, with a maximum external quantum efficiency (EQE) of 17% and a peak luminance of 91,174 cd/m2 achieved using an optimized PEI concentration of 0.025 wt% on both electron injection and hole injection sides. This study highlights the critical role of QD shell engineering and interfacial modification in achieving high-performance QLEDs for display applications.Article Citation - WoS: 1Citation - Scopus: 1Osmotic-Pressure Nematic Ordering in Suspensions of Laponite and Carboxy Methyl Cellulose(Amer Chemical Soc, 2020-10-12) Xu, Peicheng; Yazici, Ahmet F.; Erdem, Talha; Lekkerkerker, Henk N. W.; Mutlugun, Evren; Eiser, ErikaLaponite is a synthetic clay that is known to form gels in aqueous suspensions at low concentrations (0.01 g/cm(3)) Although it is expected to form lyotropic liquid crystals, such phases usually do not form, as a consequence of laponite's tendency to form gels at concentrations below the threshold for liquid crystal formation. Here we show that macroscopic, birefringent phases of laponite can be prepared through osmotic compression of a laponite solution by an aqueous solution of carboxy methyl cellulose (CMC). We present polarization imaging studies showing how the initially dilute, isotropic laponite phase shrinks while developing typical birefringence colors between crossed polarizers. Using the MichelLevy interference charts, we were able to extract the refractive index and orientation of the laponite nanodisks in the compressed region. Our observations allow us to propose a tentative state diagram, indicating the concentration regions for which we obtain optically anisotropic gels.Conference Object Citation - Scopus: 1Color Simulation and Demonstration of Perovskite Nanocrystal Filters for Wide Color Gamut Displays(Institute of Electrical and Electronics Engineers Inc., 2018-09) Genc, Sinan; Yazici, Ahmet F.; Beskazak, Emre; Uran, Can; Mutlugün, EvrenIn this study, we define spectral parameters of perovskite nanocrystals to improve LCD color gamut, replacing color filters (CFs) with perovskite based subpixels. The optimization of the CFs has been enhanced 15.8% (98.43% of Rec.2020) in simulation and 13.8% experimentally, with 97.37% color gamut coverage. © 2019 Elsevier B.V., All rights reserved.Conference Object Arrays of Multi-Color Emitting Cesium Lead Halide Perovskite Nanocrystals and Efficient White Light Generation by Tailored Anion Exchange Reactions and Electrohydrodynamic Jet Printing(Optica Publishing Group (Formerly OSA), 2018) Altıntas, Yemliha; Torun, Ilker; Yazici, Ahmet F.; Beskazak, Emre; Onses, Mustafa Serdar; Mutlugün, EvrenWe employ highly efficient and narrow band emitter Cesium-lead-halide perovskite nanocrystals, optimized by the anion exchange method, for efficient white light generation by patterning multiple lines of different colors via proposed electrohydrodynamic jet printing. © 2023 Elsevier B.V., All rights reserved.