Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Citation - WoS: 13Citation - Scopus: 14Near-Field Energy Transfer Into Silicon Inversely Proportional to Distance Using Quasi-2D Colloidal Quantum Well Donors(Wiley-VCH Verlag GmbH, 2021-09-12) Humayun, Muhammad Hamza; Hernandez-Martinez, Pedro Ludwig; Gheshlaghi, Negar; Erdem, Onur; Altintas, Yemliha; Shabani, Farzan; Demir, Hilmi VolkanSilicon is the most prevalent material system for light-harvesting applications; however, its inherent indirect bandgap and consequent weak absorption limits its potential in optoelectronics. This paper proposes to address this limitation by combining the sensitization of silicon with extraordinarily large absorption cross sections of quasi-2D colloidal quantum well nanoplatelets (NPLs) and to demonstrate excitation transfer from these NPLs to bulk silicon. Here, the distance dependency, d, of the resulting Forster resonant energy transfer from the NPL monolayer into a silicon substrate is systematically studied by tuning the thickness of a spacer layer (of Al2O3) in between them (varied from 1 to 50 nm in thickness). A slowly varying distance dependence of d(-1) with 25% efficiency at a donor-acceptor distance of 20 nm is observed. These results are corroborated with full electromagnetic solutions, which show that the inverse distance relationship emanates from the delocalized electric field intensity across both the NPL layer and the silicon because of the excitation of strong in-plane dipoles in the NPL monolayer. These findings pave the way for using colloidal NPLs as strong light-harvesting donors in combination with crystalline silicon as an acceptor medium for application in photovoltaic devices and other optoelectronic platforms.Article Citation - WoS: 11Citation - Scopus: 13Core-Crosslinking as a Pathway to Develop Inherently Antibacterial Polymeric Micelles(Wiley, 2019-08-10) Kadayifci, Melike Seyma; Gokkaya, Damla; Topuzogullari, Murat; Isoglu, Sevil Dincer; Atabey, Tugba; Arasoglu, Tulin; Ozmen, Mehmet MuratPositively charged polymeric materials have been an alternative to combat bacteria as they exhibit inherently antibacterial potency via bacteria membrane disruption. In this study, we report facile preparation of positively charged core-crosslinked polymeric micelles with inherent antibacterial properties. Spherical micelles were prepared by self-assembling of poly(4-vinylpyridine)-b-(oligoethylene glycol methyl ether methacrylate) copolymer in aqueous solution. Herein, quaternization reaction was utilized for the first time to core crosslink the micelles through the pyridine rings utilizing their hydrophobic core and thus resulting positively charged nanostructures. Dynamic light scattering (DLS) results identified that the micelles have an average hydrodynamic diameter of 114 nm with a polydispersity index ranging between 0.105 and 0.114. The electrophoretic light scattering (ELS) measurements demonstrated that the micelles have zeta potential values ranging from +38 to +63 mV. It was evident from both ELS and DLS results that the micelles in solution exhibit long-term stability as the samples were able to maintain their size and charge even after a year of storage. Further, the micelles exhibited inherently antibacterial activity against Escherichia coli and furthermore, this antibacterial efficacy was sustained over a period of 1 year. These stable core-crosslinked micelles are proposed to have great potential as antibacterial materials for long-term applications. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48393.