WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394
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Article Citation - WoS: 8Citation - Scopus: 8Writing Chemical Patterns Using Electrospun Fibers as Nanoscale Inkpots for Directed Assembly of Colloidal Nanocrystals(Royal Soc Chemistry, 2020) Kiremitler, N. Burak; Torun, Ilker; Altintas, Yemliha; Patarroyo, Javier; Demir, Hilmi Volkan; Puntes, Victor F.; Onses, M. SerdarApplications 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.Article Citation - WoS: 23Citation - Scopus: 21Tattoo-Like Multi-Color Physically Unclonable Functions(Wiley-VCH Verlag GmbH, 2023-12-07) Kiremitler, N. Burak; Esidir, Abidin; Drake, Gryphon A.; Yazici, Ahmet Faruk; Sahin, Furkan; Torun, Ilker; Onses, M. SerdarAdvanced 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. Tattoo-like multi-color encoding layers based on random processing of semiconductor nanocrystals of varied composition and geometry are reported. Additive deposition via chaotic electrospraying enables randomness and multiplexing, whereas the tattoo approach provides substrate independence.imageArticle Citation - WoS: 6Citation - Scopus: 5Photoluminescent and Superhydrophobic Nanocomposites of Perovskite Nanocrystals(Elsevier, 2024-03) Ocal, Sema Karabel; Celik, Nusret; Onses, M. Serdar; Mutlugun, Evren; Karabel Ocal, SemaPerovskite nanocrystals (PNCs) have found extensive utility across diverse technological applications in optoelectronics; nevertheless, their susceptibility to environmental instability poses a significant constraint on their practicality. Within this investigation, we present a novel and facile approach for the development of highly stable superhydrophobic PNCs. These engineered superhydrophobic perovskite nanocrystal composites, referred to as HSNPs@PNCs, demonstrate remarkable optoelectronic attributes, provided that their inherent instability can be effectively mitigated. HSNPs@PNCs manifest an impressive water contact angle of 172 degrees and an exceedingly low sliding angle of 1 degrees, thus showcasing their exceptional superhydrophobicity. Of particular note is the extraordinary stability exhibited by HSNPs@PNCs despite aqueous environments, thermal fluctuations, and UV exposure. Remarkably, even after a prolonged 30 -day immersion in water, this nanocomposite maintains an outstanding emission efficiency of 75 %. Furthermore, the method of application through a spray deposition technique circumvents sample size limitations, thereby amplifying their suitability for industrial applications. Moreover, this study extends the practicality of HSNPs@PNCs by enabling their homogeneous coating onto various surfaces such as glass, fabric, and aluminum, yielding luminescent superhydrophobic surfaces. This approach liberates the substrates from constraints, significantly broadening the potential spectrum of applications for these materials within diverse industrial and technological domains.Article Citation - WoS: 88Citation - Scopus: 83Organic Light-Emitting Physically Unclonable Functions(Wiley-VCH Verlag GmbH, 2021-12-22) Kayaci, Nilgun; Ozdemir, Resul; Kalay, Mustafa; Kiremitler, N. Burak; Usta, Hakan; Onses, M. SerdarThe 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.Article Citation - WoS: 51Citation - Scopus: 51Multiplexed Patterning of Cesium Lead Halide Perovskite Nanocrystals by Additive Jet Printing for Efficient White Light Generation(Elsevier Science SA, 2020-01) Altintas, Yemliha; Torun, Ilker; Yazici, Ahmet Faruk; Beskazak, Emre; Erdem, Talha; Onses, M. Serdar; Mutlugun, Evren; Serdar Onses, M.Inorganic perovskite nanocrystals (PNCs) offer the ability to precisely but also flexibly control the peak emission wavelength while also possessing narrow-band emission spectra and high quantum yields. Owing to these features, PNCs have been already employed as color converters on LEDs. Nevertheless, the anion exchange reactions that prevent the blending of perovskites of different colors remain as an important bottleneck. As a remedy to this issue, here we employ additive jet printing to form separated stripes of these nanocrystals. Within this framework, we first present the synthesis of CsPbBr3 and CsPbBrxI3-x nanocrystals spanning the whole visible regime and optimize the cleaning procedure to obtain PNCs possessing photoluminescence quantum yields as high as 91% and emission linewidths as narrow as 15 nm, making them suitable for high quality white light generation. Next, we employ electrohydrodynamic jet printing to form closely spaced stripes of PNCs of various colors and integrated these films with a blue LED to create a white LED. Our proof-of-concept LED achieves high photometric performance as it possesses a color rendering index of 91.3, luminous efficacy of optical radiation > 300 lm/W-opt, and correlated color temperature of ca. 7000 K. We believe that additive jet printing technique will pave the way for a ubiquitous use of these PNCs in light-emitting devices in the near future.