Browsing by Author "Nizamoğlu, S."
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Open Access FRET-LEDs involving colloidal quantum dot nanophosphors(Webcom Communications, 2010) Nizamoğlu, S.; Sari, E.; Baek, J. H.; Lee, I. H.; Sun, X. W.; Demir, Hilmi VolkanSemiconductor nanocrystal quantum dots (NQD) with their narrow and tuneable emission are promising candidates to serve as color convertors integrated on light-emitting diodes (LEDs). The use of nonradiative energy transfer, also known as Förster-type resonance energy transfer (FRET), in such NQD nanophosphors provides additional benefits for color-conversion in solid state lighting. In this paper we discuss these NQD-integrated FRET-LEDs for lighting applications.Item Open Access Highly efficient nonradiative energy transfer using charged CdSe/ZnS nanocrystals for light-harvesting in solution(American Institute of Physics, 2009-07-20) Mutlugün, E.; Nizamoğlu, S.; Demir, Hilmi VolkanWe propose and demonstrate highly efficient nonradiative Förster resonance energy transfer (FRET) facilitated by the use of positively charged CdSe/ZnS core-shell nanocrystals (NCs) for light-harvesting in solution. With rhodamine B dye molecules used as the acceptors, our time-resolved photoluminescence measurements show substantial lifetime modifications of these amine-functionalized NC donors from 18.16 to 1.88 ns with FRET efficiencies >90% in solution. These strong modifications allow for light-harvesting beyond the absorption spectral range of the acceptor dye molecules.Item Open Access Nanoengineering InP quantum dot-based photoactive biointerfaces for optical control of neurons(Frontiers Media S.A., 2021-06-23) Karatum, O.; Aria, M. M.; Eren, G. Ö.; Yıldız, E.; Melikov, R.; Srivastava, S. B.; Sürme, S.; Bakış Doğru, I.; Jalali, H. B.; Ulgut, Burak; Şahin, A.; Kavaklı, İ. H.; Nizamoğlu, S.Light-activated biointerfaces provide a non-genetic route for effective control of neural activity. InP quantum dots (QDs) have a high potential for such biomedical applications due to their uniquely tunable electronic properties, photostability, toxic-heavy-metal-free content, heterostructuring, and solution-processing ability. However, the effect of QD nanostructure and biointerface architecture on the photoelectrical cellular interfacing remained unexplored. Here, we unravel the control of the photoelectrical response of InP QD-based biointerfaces via nanoengineering from QD to device-level. At QD level, thin ZnS shell growth (∼0.65 nm) enhances the current level of biointerfaces over an order of magnitude with respect to only InP core QDs. At device-level, band alignment engineering allows for the bidirectional photoelectrochemical current generation, which enables light-induced temporally precise and rapidly reversible action potential generation and hyperpolarization on primary hippocampal neurons. Our findings show that nanoengineering QD-based biointerfaces hold great promise for next-generation neurostimulation devices.