Browsing by Author "Kiremitler, N. Burak"

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Inkjet Printing of Aqueous Silver Inks on Water-Soluble Fabrics for Transient Electronics Applications
(AMER CHEMICAL SOC, 2024) Gozutok-Onses, Zehra; Kiremitler, N. Burak; Ozbasaran, Aleyna; Huang, Xian; Onses, Mustafa Serdar; Usta, Hakan; 0000-0002-0618-1979; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Gozutok-Onses, Zehra; Usta, Hakan
There is an urgent need to develop practical routes for manufacturing transient electronic devices to tackle the emerging issue of electronic waste and enable next-generation devices. This study reports additive patterning of conductive layers on industrially available water-soluble nonwoven fabrics composed of poly(vinyl alcohol) (PVA). Aqueous inks composed of reactive silver precursors can be practically patterned over water-soluble fabrics by inkjet printing. The efficient deposition of materials with droplet volumes on the order of picoliters ensures the generation of conductive patterns on a water-soluble fabric using a solution-processable fabrication with aqueous inks. The fabrication of conductive electrodes and transience behavior are studied on PVA fabrics with two different degrees of hydrolysis, providing tunability in the temperature-dependent degradation of the substrate. The application of the printed conductive pads is demonstrated in resistive heaters. The temperature of the fabric can exceed 100 degrees C in less than 15 s at a safe voltage of 3 V. The heater exhibits stable operation under cyclic heating and cooling. The presented approach presents key opportunities in additive patterning of aqueous solutions and colloidal dispersions over water-soluble substrates for transient device applications.
Natural Wax-Stabilized Perovskite Nanocrystals as Pen-on-Paper Inks and Doughs
(AMER CHEMICAL SOC, 2022) Ocal, Sema Karabel; Kiremitler, N. Burak; Yazici, Ahmet Faruk; Celik, Nusret; Mutlugun, Evren; Onses, M. Serdar; 0000-0003-2747-7856; 0000-0003-3715-5594; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Yazici, Ahmet Faruk; Mutlugun, Evren
Perovskite nanocrystals (PNCs) are emerging luminescent materials for a wide range of technological applications. The broad adaptation of PNCs will be greatly improved by addressing their intrinsically low stability and developing processes for their assembly into 2D and 3D structures using facile approaches. Inspired by the mechanism of natural protection of leaves, this paper proposes natural carnauba wax (CW) as an encapsulation material for PNCs. The synthesis of PNCs is performed in the presence of CW, which is derived from the leaves of Copernicia prunifera palm. CW acts as a solvent and replaces the commonly used octadecene in the preparation of PNCs. The facile synthesis in CW results in PNCs with greatly improved thermal, water, and air stability. Furthermore, the thermal and mechanical properties make PNC-Wax a highly suitable solid ink for versatile processing of these materials into 2D and 3D architectures. PNC-Wax can be printed via a pen-on-paper approach by heating at modest temperatures. The rapid plasticization of PNC-Wax by mechanical agitation enables hand-shaping of the material in a manner similar to playdoughs, which would possibly enable the versatile use of this material for various applications.
Organic Light-Emitting Physically Unclonable Functions
(WILEY-V C H VERLAG GMBHPOSTFACH 101161, 69451 WEINHEIM, GERMANY, 2021) Kayaci, Nilgun; Ozdemir, Resul; Kalay, Mustafa; Kiremitler, N. Burak; Usta, Hakan; Onses, M. Serdar; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Ozdemir, Resul; Usta, Hakan
The development of novel physically unclonable functions (PUFs) is of growing interest and fluorescent organic semiconductors (f-OSCs) offer unique advantages of structural versatility, solution-processability, ease of processing, and great tuning ability of their physicochemical/optoelectronic/spectroscopic properties. The design and ambient atmosphere facile fabrication of a unique organic light-emitting physically unclonable function (OLE-PUF) based on a green-emissive fluorescent oligo(p-phenyleneethynylene) molecule is reported. The OLE-PUFs have been prepared by one-step, brief (5 min) thermal annealing of spin-coated nanoscopic films (approximate to 40 nm) at a modest temperature (170 degrees C), which results in efficient surface dewetting to form randomly positioned/sized hemispherical features with bright fluorescence. The random positioning of molecular domains generated the unclonable surface with excellent uniformity (0.50), uniqueness (0.49), and randomness (p > 0.01); whereas the distinctive photophysical and structural properties of the molecule created the additional security layers (fluorescence profile, excited-state decay dynamics, Raman mapping/spectrum, and infrared spectrum) for multiplex encoding. The OLE-PUFs on substrates of varying chemical structures, surface energies and flexibility, and direct deposition on goods via drop-casting are demonstrated. The OLE-PUFs immersed in water, exposed to mechanical abrasion, and read-out repeatedly via fluorescence imaging showed great stability. These findings clearly demonstrate that rationally engineered solution-processable f-OSCs have a great potential to become a key player in the development of new-generation PUFs.
Tattoo-Like Multi-Color Physically Unclonable Functions
(WILEY, 2023) Kiremitler, N. Burak; Esidir, Abidin; Drake, Gryphon A.; Yazici, Ahmet Faruk; Sahin, Furkan; Torun, Ilker; Kalay, Mustafa; Kelestemur, Yusuf; Demir, Hilmi Volkan; Shim, Moonsub; Mutlugun, Evren; Onses, M. Serdar; 0000-0003-2747-7856; /0000-0003-3715-5594; AGÜ, Mühendislik Fakültesi, Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü; Yazici, Ahmet Faruk; Mutlugun, Evren
Advanced anti-counterfeiting and authentication approaches are in urgent need of the rapidly digitizing society. Physically unclonable functions (PUFs) attract significant attention as a new-generation security primitive. The challenge is design and generation of multi-color PUFs that can be universally applicable to objects of varied composition, geometry, and rigidity. Herein, tattoo-like multi-color fluorescent PUFs are proposed and demonstrated. Multi-channel optical responses are created by electrospraying of polymers that contain semiconductor nanocrystals with precisely defined photoluminescence. The universality of this approach enables the use of dot and dot-in-rod geometries with unique optical characteristics. The fabricated multi-color PUFs are then transferred to a target object by using a temporary tattoo approach. Digitized keys generated from the red, green and blue fluorescence channels facilitate large encoding capacity and rapid authentication. Feature matching algorithms complement the authentication by direct image comparison, effectively alleviating constraints associated with imaging conditions. The strategy that paves the way for the development of practical, cost-effective, and secure anticounterfeiting systems is presented.
Writing chemical patterns using electrospun fibers as nanoscale inkpots for directed assembly of colloidal nanocrystals
(ROYAL SOC CHEMISTRY, THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND, 2020) Kiremitler, N. Burak; Torun, Ilker; Altintas, Yemliha; Patarroyo, Javier; Demir, Hilmi Volkan; Puntes, Victor F.; Mutlugun, Evren; Onses, M. Serda; 0000-0001-9820-6565; 0000-0002-3703-666X; 0000-0003-1793-112X; 0000-0001-8996-9499; AGÜ, Mühendislik Fakültesi, Elektrik - Elektronik Mühendisliği Bölümü
Applications that range from electronics to biotechnology will greatly benefit from low-cost, scalable and multiplex fabrication of spatially defined arrays of colloidal inorganic nanocrystals. In this work, we present a novel additive patterning approach based on the use of electrospun nanofibers (NFs) as inkpots for end-functional polymers. The localized grafting of end-functional polymers from spatially defined nanofibers results in covalently bound chemical patterns. The main factors that determine the width of the nanopatterns are the diameter of the NF and the extent of spreading during the thermal annealing process. Lowering the surface energy of the substrates via silanization and a proper choice of the grafting conditions enable the fabrication of nanoscale patterns over centimeter length scales. The fabricated patterns of end-grafted polymers serve as the templates for spatially defined assembly of colloidal metal and metal oxide nanocrystals of varying sizes (15 to 100 nm), shapes (spherical, cube, rod), and compositions (Au, Ag, Pt, TiO2), as well as semiconductor quantum dots, including the assembly of semiconductor nanoplatelets.