Browsing by Author "Erdem, T."

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Use of Confocal Microscopy to Monitor Structural Transformations in Nanopillars Based on DNA and CdSe/CdZnSe Quantum Dots
(Springer, 2023) Motevich, I. G.; Erdem, T.; Akrema, A.; Maskevich, S. A.; Strekal, N. D.
Chip system prototypes in the form of nanopillars were created from DNA complexes with CdSe/CdZnSe/ZnS quantum dots immobilized on a plasmonic gold fi lm by the use of vacuum deposition technology and inorganic synthesis. The design and presence of terminal DNA labeled with Cy3 cyanine dyes makes it possible to carry out the hybridization reaction of this terminal strand with complementary DNA and to control the process by variation of the giant Raman scattering (GRS) and the fluorescence signal. The effect of molecular recognition of complementary DNA is accompanied by a change in the GRS spectrum, a 20-fold increase in the fluorescence intensity, and a decrease in the duration of fluorescence decay.
Fully Flexible, Low-Cost, Environmentally Friendly Yarn-Based Inp/Ag Nw Photodetectors for UV-Visible Light Detection
(SPIE, 2025) Savaş, M.; Akrema, A.; Ocal, S.K.; Erdem, T.
We report the fabrication and investigate of a novel photodetector using a heterostructure of InP quantum dots (QDs) and silver nanowires (Ag NWs) incorporated into yarn. This device is simple, scalable, low-cost, flexible, and functions under ambient conditions. Ag NWs and red-emitting InP QDs were separately synthesized via chemical methods and mixed in a specific ratio to coat functional yarns, which were then knitted into fabrics. The photodetector benefits from the excellent electrical conductivity of Ag NWs and the strong optical absorption of InP QDs. It shows enhanced photoelectric response in both UV and visible regions. At 405 nm illumination, the device achieves a photoresponsivity of 5.8 mA W-1 and a detectivity of 2 × 1010 Jones-values comparable to or exceeding those of similar devices. The enhanced performance is attributed to efficient charge transfer enabled by favorable band alignment between Ag NWs and InP QDs, along with synergistic effects from nanostructure dimensionality and quantum confinement. The device's combination of flexibility, sensitivity, and cost-efficiency makes it a strong candidate for wearable UV-visible photodetectors. © 2025 SPIE. All rights reserved.
Citation - WoS: 25
Citation - Scopus: 26
A Simple Approach to Prepare Self-Assembled, Nacre-Inspired Clay/Polymer Nanocomposites
(Royal Soc Chemistry, 2020) Xu, P.; Erdem, T.; Eiser, E.
Inspired by the relationship between the well-ordered architecture of aragonite crystals and biopolymers found in natural nacre, we present a facile strategy to construct large-scale organic/inorganic nacre-mimetics with hierarchical structureviaa water-evaporation driven self-assembly process. We connect LAPONITE (R)-nanoclay platelets with each other using carboxymethyl cellulose, a cellulose derivative, thus creating thin, flexible films with a local brick-and-mortar architecture. The dried films show a pronounced resistance against tensile forces allowing for stronger thin films than nacre. In terms of functionalities, we report excellent glass-like transparency along with exceptional shape-persistent flame shielding. We also demonstrate that through metal ion-coordination we can further strengthen the interactions between the polymers and the nanoclays, and thus enhanced mechanical, and thermal properties as well as resistance against swelling and dissolution in aqueous environments. We believe that our simple pathway to fabricate such versatile polymer/clay nanocomposites can open avenues for inexpensive production of environmentally friendly, biomimetic materials in aerospace, wearable electrical devices, and in the food packaging industry.
Citation - WoS: 3
Citation - Scopus: 4
Tuning Optical Properties of Self-Assembled Nanoparticle Network with External Optical Excitation
(American Institute of Physics Inc., 2021) Şenel, Z.; İçöz, K.; Erdem, T.
DNA-driven self-assembly enables precise positioning of the colloidal nanoparticles owing to specific Watson-Crick interactions. Another important feature of this self-assembly method is its reversibility by controlling the temperature of the medium. In this work, we study the potential of another mechanism to control the binding/unbinding process of DNA-functionalized gold nanoparticles. We employ laser radiation that can be absorbed by the gold nanoparticles to heat their network and disassociate it. Here, we show that we can actively control the optical properties of the nanoparticle network by external optical excitation. We find out that by irradiating the structure with a green hand-held laser, the total transmittance can increase by ∼30% compared to the transmittance of the sample not irradiated by the laser. Similarly, the optical microscopy images indicate the transformation of the nanoparticle network from opaque to transparent, while the nanoparticles formed a network again after the laser irradiation stopped. Our results prove that the optical excitation can be used to tailor the structure and thus the optical properties of the DNA-self-assembled nanoparticle networks. © 2021 Elsevier B.V., All rights reserved.