PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7645
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Article A Comparative Study on Hydroxyl and Ether Functionalized Ionic Liquid Additives for Defect Passivation and Stability in Perovskite Solar Cells(Royal Soc Chemistry, 2025) Siyahjani Gültekin, S.; Turgut, S.B.; Ozdemir, Saliha; Gültekin, B.; Varlikli, C.This study systematically investigates the effects of two ionic liquid (IL) additives, 2-(2-methoxyethoxy)-N,N-bis(2-(2-methoxyethoxy)ethyl)-N-methylethanaminium iodide (EtAI) and 2-hydroxy-N,N-bis(2-hydroxyethyl)-N-methylethanaminium iodide (HOAI), on the structural, morphological, optical, and photovoltaic properties of triple-cation perovskite thin films. FT-IR, XRD, XPS, SEM, and AFM analyses were employed to characterize additive-induced modifications, while UV-Vis, PL, and TRPL measurements were utilized to evaluate their optical properties. SEM and AFM results reveal that the hydroxyl (-OH) groups in HOAI and etheric groups in EtAI significantly improve film morphology by enhancing grain size, reducing surface roughness, and refining grain boundaries, thereby promoting more efficient charge transport. Photovoltaic characterization revealed that the film with 3 mmol HOAI exhibited a maximum reverse-scan power conversion efficiency (PCE) of 17.65%, retaining approximately 85% of its initial efficiency after 1000 hours under ambient conditions. In contrast, the film with 1 mmol EtAI achieved a reverse-scan PCE of 17.17%, although higher EtAI concentrations adversely affected stability. These findings provide valuable insights into the interplay between additive chemistry and perovskite film quality, offering a promising route for improving the efficiency and long-term performance of perovskite solar cells. This record is sourced from MEDLINE/PubMed, a database of the U.S. National Library of MedicineArticle Creatinine-On Colorimetric Elisa-Based Serum Creatinine Detection in a Microfluidic Device(Royal Soc Chemistry, 2025) Karakuzu, Betul; Tekin, H. CumhurChronic kidney diseases (CKDs), which often end in kidney failure for many people around the world, have an important place in public health given that they also trigger other diseases. Therefore, the development of fast and cost-effective diagnostic technologies enables effective monitoring of patients and early diagnosis. Here, using the Enzyme-Linked Immunosorbent Assay (ELISA) principle, serum creatinine concentrations were determined using the developed lab-on-a-chip (LOC) platform. In this system, which was termed "creatinine-on-a-chip", colorimetric ELISA protocol was applied to determine creatinine levels in a microfluidic chip functionalized with creatinine-specific antibodies. Creatinine detection was performed by quantifying the absorbance difference between the detection and reference channels, normalized to the reference signal within the microfluidic chip. The detection signal intensity varied depending on the region selected along the microfluidic channel. The adsorption of the capture antibody used for surface functionalization, which was particularly more pronounced near the inlet region, played a critical role in the detection signal. These findings suggest that random selection of the detection area can lead to significant signal variability, and that careful selection of a well-characterized region is essential for improving detection performance. With this developed system, creatinine was detected with high sensitivity in the linear range of 1-20 mu g mL-1, both spiked in phosphate buffered saline (PBS) and fetal bovine serum (FBS). Using the creatinine-on-a-chip, serum creatinine analysis can be performed rapidly (similar to 15 min) in a cost-effective manner ($1.05 per test).Article Citation - WoS: 2Citation - Scopus: 3Dynamic Fluidic Manipulation in Microfluidic Chips With Dead-End Channels Through Spinning: the Spinochip Technology for Hematocrit Measurement, White Blood Cell Counting and Plasma Separation(Royal Soc Chemistry, 2025) Oksuz, Cemre; Tekin, Hüseyin Cumhur; Bicmen, Can; Tekin, H. CumhurCentrifugation is crucial for size and density-based sample separation, but low-volume or delicate samples suffer from loss and impurity issues during repeated spins. We introduce the "Spinochip", a novel microfluidic system utilizing centrifugal forces for efficient filling of dead-end microfluidic channels. The Spinochip enables versatile fluid manipulation with a single reservoir for both inlet and outlet functions. It expels compressed air, facilitating fluid flow, and offers programmable filling mechanisms based on the hydraulic resistance of microfluidic channels. Compatible with a basic centrifuge, it allows sequential filling, internal mixing, and collection in straight microfluidic channels by simply adjusting the spinning speed, eliminating the need for complex valving. We demonstrated the Spinochip's efficacy in blood testing, where it successfully separated blood components, such as plasma, buffy coat, and red blood cells, from a single drop using centrifugation alone. This system enabled simultaneous hematocrit (R2 >0.99) and total white blood cell (R2 >0.93) quantification within a single microfluidic channel without the need for staining or special reagents. Remarkably, the Spinochip can perform hematocrit measurements on as little as 100 nL of blood, potentially paving the way for less invasive blood analysis. This innovative approach unlocks new possibilities in microfluidics, providing precise fluidic control and centrifugation for sample volumes as small as a few nanoliters.Article Citation - WoS: 1Anisotropic Structural, Vibrational, Electronic, Optical, and Elastic Properties of Single-Layer Hafnium Pentatelluride: an <i>ab Initio</I> Study(Royal Soc Chemistry, 2024) Dogan, Kadir Can; Cetin, Zebih; Yagmurcukardes, MehmetMotivated by the highly anisotropic nature of bulk hafnium pentatelluride (HfTe<INF>5</INF>), the structural, vibrational, electronic, optical, and elastic properties of single-layer two-dimensional (2D) HfTe<INF>5</INF> were investigated by performing density functional theory (DFT)-based first-principles calculations. Total energy and geometry optimizations reveal that the 2D single-layer form of HfTe<INF>5</INF> exhibits in-plane anisotropy. The phonon band structure shows dynamic stability of the free-standing layer and the predicted Raman spectrum displays seven characteristic Raman-active phonon peaks. In addition to its dynamic stability, HfTe<INF>5</INF> is shown to exhibit thermal stability at room temperature, as confirmed by quantum molecular dynamics simulations. Moreover, the obtained elastic stiffness tensor elements indicate the mechanical stability of HfTe<INF>5</INF> with its orientation-dependent soft nature. The electronic band structure calculations show the indirect-gap semiconducting behavior of HfTe<INF>5</INF> with a narrow electronic band gap energy. The optical properties of HfTe<INF>5</INF>, in terms of its imaginary dielectric function, absorption coefficient, reflectance, and transmittance, are shown to exhibit strong in-plane anisotropy. Furthermore, structural analysis of several point defects and their oxidized structures was performed by means of simulated STM images. Among the considered vacancy defects, namely , , V<INF>Te<INF>out</INF></INF>, V<INF>Te<INF>in</INF></INF>, , and V<INF>Hf</INF>, the formation of V<INF>Te<INF>out</INF></INF> is revealed to be the most favorable defect. While and V<INF>Hf</INF> defects lead to local magnetism, only the oxygen-substituted V<INF>Hf</INF> structure possesses magnetism among the oxidized defects. Moreover, it is found that all the bare and oxidized vacant sites can be distinguished from each other through the STM images. Overall, our study indicates not only the fundamental anisotropic features of single-layer HfTe<INF>5</INF>, but also shows the signatures of feasible point defects and their oxidized structures, which may be useful for future experiments on 2D HfTe<INF>5</INF>.Article Citation - Scopus: 3A Reaction-Based Scenario for Fluorescence Probing of Au(iii) Ions in Human Cells and Plants(Royal Soc Chemistry, 2023) Eren, Merve Cevik; Eren, Ahmet; Dartar, Suay; Kaya, Beraat Umur; Ucuncu, Muhammed; Varlikli, Canan; Emrullahoglu, MustafaA BODIPY-based fluorophore decorated with a gold specific reactive handle (e.g., 2-alkynylallyl alcohol) displayed a ratiometric fluorescence change in response to Au3+ ions with extraordinary selectivity over other competing metal species, including Hg2+, Cu2+, Zn2+ and Pd2+. By way of a gold-catalyzed intramolecular cyclisation-isomerisation reaction sequence, a BODIPY construct with an extended p-conjugation transformed into a new structure with a relatively short p-system. This unique chemical transformation was accompanied by, and resulted in, a dramatic shift in the emission and absorption wavelength, which could be monitored as distinct changes in the color of the solution's emission. Apart from its outstanding analytical performance in solution, including a quick response time (<10 s), unique specificity, a high-fold ratio-metric change (62-fold), and a remarkably low detection limit (358 nM), the probe also proved useful in monitoring Au3+ ions in human cells and plants (e.g., Nicotiana benthamiana).