Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Start date: 2024Publisher: search.filters.publisher.Amer Chemical Soc

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  • Article
    Temporal Coherence of Single Photons Emitted by Hexagonal Boron Nitride Defects at Room Temperature
    (Amer Chemical Soc, 2026) Martinez-Pons, Juan Vidal; Kim, Sang Kyu; Behrens, Max; Izquierdo-Molina, Alejandro; Menendez Rua, Adolfo; Pacal, Serkan; Anton-Solanas, Carlos
    Color centers in hexagonal boron nitride (hBN) emerge as promising quantum light sources at room temperature, with potential applications in quantum communications, among others. The temporal coherence of emitted photons (i.e., their capacity to interfere and distribute photonic entanglement) is essential for many of these applications. Hence, it is crucial to study and determine the temporal coherence of this emission under different experimental conditions. In this work, we report the coherence time of the single photons emitted by an hBN defect in a nanocrystal at room temperature, measured via Michelson interferometry. The visibility of this interference vanishes when the temporal delay between the interferometer arms is a few hundred femtoseconds, highlighting that the phonon dephasing processes are 4 orders of magnitude faster than the spontaneous decay time of the emitter. We also analyze the single photon characteristics of the emission via correlation measurements, defect blinking dynamics, and its Debye-Waller factor. Our room temperature results highlight the presence of a strong electron-phonon coupling, suggesting the need to work at cryogenic temperatures to enable quantum photonic applications based on photon interference.
  • Article
    Characterization and Energetic Property Evaluation of Novel Energetic Salts and Co-Crystals Formed with Nitropyrazoles and Pyridines
    (Amer Chemical Soc, 2025) Atceken, Nurunnisa; Bauer, Kaylyn M.; Nichol, Gary S.; Morrison, Carole A.; Pulham, Colin R.
    Nitropyrazoles are promising candidates to replace conventional explosives as they generally have positive heats of formation, good thermal stabilities, low friction and impact sensitivities and high energetic performance. In this study, 3,5-dinitropyrazole (DNP) and 3,4,5-trinitropyrazole (TNP) were combined with a series of pyridine derivatives to create nine new multicomponent crystals. Single-crystal X-ray diffraction shows that the herringbone-type packing observed in both DNP and TNP can be significantly altered to form puckered, wave-like and layered packing motifs. Differential scanning calorimetry and thermogravimetric analysis measurements show significant alteration in the thermal properties of the new materials, suggesting that the processing and energetic properties of DNP and TNP can be efficiently tuned through multicomponent crystallization. Preliminary impact sensitivity measurements performed on some of the materials also suggest that the mechanochemical responses of DNP and TNP can be altered through changing the crystal packing motifs. Overall, this study highlights the important role that multicomponent crystallization can play in tuning the structure/materials property relationships in energetic materials research.
  • Article
    Protection of N-Type (Ni,Fe)TiSb Half-Heusler Materials Against Static and Cyclic Oxidation Using a Si-Doped Cr Coating
    (Amer Chemical Soc, 2025) Gurtaran, Mikdat; Zhang, Zhenxue; Li, Xiaoying; Dong, Hanshan
    In this study, Cr-Si coatings were deposited on N-type (Ni,Fe)TiSb thermoelectric (TE) materials by using a closed-field unbalanced magnetron sputtering PVD technique. Oxidation behavior was evaluated under both isothermal (static) conditions (500 degrees C for 10 h and 600 degrees C for 50 h) and thermal cycling regimens (500 and 600 degrees C for 10 or 50 1 h cycles). Mass gain, surface morphology, cross-sectional microstructure, elemental distribution, and phase composition were examined by using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Regardless of exposure mode, uncoated samples oxidized severely: a duplex scale formed, consisting of an outer TiO2 layer and a subjacent NiSb-rich zone, accompanied by extensive cracking and delamination. In sharp contrast, the Cr-Si coatings remained thermally stable and highly oxidation-resistant, maintaining the substrate's integrity during both static and cyclic tests. After exposure, coated samples showed negligible mass gain, no discernible morphological change, and no mechanical damage, confirming that the Cr-Si layer markedly enhances thermal durability and prevents surface degradation.
  • Article
    Molecular Engineering of Exchange Bias in Fe3GeTe2/Molecule Heterostructures
    (Amer Chemical Soc, 2025) Sharma, Mayank; Jo, Junhyeon; Avedissian, Garen; Bayindir, Bertug; Kang, Jun; Sahin, Hasan; Hueso, Luis E.
    Molecules offer a versatile route to tailor magnetism through chemical design and spin-state control. When integrated with surface-sensitive layered magnets, molecules can not only exhibit tunable magnetic properties or even activate distinct magnetic phases but can also interact with the layered magnets to manipulate their magnetic dynamics. Here, we demonstrate tunable exchange bias in hybrid heterostructures composed of the layered ferromagnet Fe3GeTe2 (FGT) and metallophthalocyanine (MPc) molecules having different central transition ions: MnPc, ZnPc, and H2Pc. The MnPc/FGT system exhibits a robust exchange bias of 1000 Oe at 10 K, with a record-high exchange bias-to-coercivity ratio of 0.37, attributed to the antiferromagnetic nature of MnPc. Surprisingly, the diamagnetic ZnPc induces a finite exchange bias of 200 Oe, highlighting the contribution of the emerging spinterface effect. In contrast, the metal-free H2Pc yields no exchange bias, underscoring the essential role of designed molecules for magnetic interaction. First-principles calculations reveal energetically favorable stacking configurations and spin alignments, in agreement with experimental observations. These results highlight the potential of molecular functionalization on magnetism, enabling the on-demand engineering of layered magnetic systems.
  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Electrochemical Sensors for Rapid Cardiovascular Disease Diagnostics
    (Amer Chemical Soc, 2025) Sanko, Vildan; Tekin, H. Cumhur
    Cardiovascular diseases (CVDs) remain a leading cause of death, particularly in developing countries, where their incidence continues to rise. Traditional CVD diagnostic methods are often time-consuming and inconvenient, necessitating more efficient alternatives. Rapid and accurate measurement of cardiac biomarkers released into body fluids is critical for early detection, timely intervention, and improved patient outcomes. Electrochemical methods offer a robust solution by enabling rapid, sensitive, selective, and multiplex detection of CVD biomarkers, paving the way for early diagnosis and treatment advancements. This review highlights the performance and potential of electrochemical sensors for detecting specific CVD biomarkers and related organic molecules. It explores electrochemical sensing mechanisms, their evolution, the integration of nanotechnology, and diverse sensing platforms. It also examines emerging technologies such as microfluidic, smartphone-integrated sensors, and microneedle- and tattoo-based sensors. Challenges and opportunities in integrating electrochemical sensors into point-of-care (POC) and wearable devices are discussed. Finally, the review compares commercial CVD sensors with existing methods and outlines future directions to advance the field.
  • Article
    Enabling Fluorescence Lifetime Imaging Multiplexing Using UnaG Through Its Modification With Canonical and Noncanonical Amino Acids
    (Amer Chemical Soc, 2025) Terekhova, Valentina V.; Bodunova, Daria V.; Gorokhov, Egor S.; Tsoraev, Georgy V.; Sidorenko, Svetlana V.; Vasilev, Ruslan A.; Kirpichnikov, Mikhail P.
    Fluorogen-activating proteins are powerful molecular tools for microscopy, including functional imaging. These proteins serve as an alternative to GFP-like proteins, as they do not require oxygen for chromophore maturation. However, the restricted selectivity of proteins to chromophores, combined with the limited number of spectral channels of conventional fluorescent microscopes, hinders the development of multicolor synthetic dyes. Additionally, the poor cell and tissue permeability of synthetic chromophores further limits their utility. In this work, we address these challenges by combining time-resolved methods with the rational design of the UnaG protein, which utilizes bilirubin as a natural chromophore. To turn UnaG into a palette of probes for fluorescence lifetime imaging microscopy (FLIM), we solved two practical problems: first, we determined the limits of bilirubin lifetime variations in response to changes in the protein structure and, second, we determined what minimal structural changes can be reliably distinguished by lifetime analysis in cellula. Combining classical point mutagenesis and the translational introduction of noncanonical amino acids, we generated UnaG with fluorescence lifetimes ranging from hundreds of picoseconds to nanoseconds. We explored the potential for further modification of the UnaG protein matrix to optimize spectral and temporal characteristics of bilirubin fluorescence and its quantitative detection through time-resolved approaches.
  • Article
    Citation - WoS: 4
    Citation - Scopus: 2
    Elastic and Anelastic Behavior Associated With Structural Transitions in CsPbBr3
    (Amer Chemical Soc, 2025) Luo, Pingjing; He, Zhengwang; Yang, Dexin; Aktas, Oktay; Ding, Xiangdong; Zhang, Xuefeng
    Strain coupling and relaxation dynamics critically influence the photovoltaic and photoluminescent performances of metal halide perovskites. Here, resonant ultrasound spectroscopy is employed to study the elastic and anelastic properties associated with the octahedral tilting transitions in the optoelectronic semiconductor CsPbBr3 over the temperature range 303-468 K. The cubic-to-tetragonal transition near 405 K is marked by pronounced elastic softening accompanied by a sharp increase in acoustic loss. High anelastic loss below this transition reveals the presence of mobile ferroelastic twin walls that become pinned by lead vacancies at a temperature interval near 380 K in the tetragonal phase. The elastic softening in the cubic phase is strongly correlated to dynamic effects such as the local polar fluctuations. This local disordered effect is further verified by the anomalously high attenuation in the orthorhombic structure, in which the ferroelastic twin walls might become mobile.
  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Monomer-Engineered Quinone-Based Conjugated Polymers for High-Rate Aqueous Zinc-Ion Batteries
    (Amer Chemical Soc, 2025) Canakci, Utku Cem; Gecalp, Yasmin; Canturk, Batu Sercan; Erdogmus, Mustafa; Erozen, Yaren Naz; Buyukcakir, Onur
    Conjugated polymers (CPs) with their extended pi-conjugated structures have recently attracted tremendous attention as organic cathodes in aqueous zinc-ion batteries (AZIBs). In this study, two quinone-pyrrole conjugated polymers, QpCP-1 (benzoquinone monomer) and QpCP-2 (anthracenetetrone monomer), were synthesized to investigate the impact of monomer engineering on electrochemical performance, aiming to enhance specific capacity without sacrificing rate performance and cycle life. At 0.1 A g-1, QpCP-1 delivered a higher specific capacity (178 mA h g-1) than QpCP-2 (134 mA h g-1). However, while QpCP-1's capacity declined with increased current density, QpCP-2 demonstrated superior rate capability, retaining 78% of its initial capacity when the current density increased 20-fold (from 0.1 to 2.0 A g-1). This enhanced rate performance is attributed to QpCP-2's extended conjugated structure and increased accessible quinone-rich redox-active sites. Furthermore, QpCP-2 underwent gradual activation, resulting in a 30% increase in specific capacity, and demonstrated remarkable cycling stability over 10,000 cycles at 2.0 A g-1. The charge storage mechanism involving the coinsertion of H+ and Zn2+ was investigated through a series of ex situ characterization techniques. This work provides insights into the potential of CPs in AZIBs by elucidating the impact of monomer engineering and structural influences on electrochemical performance.
  • Article
    Fabrication of Flexible Nanoporous Platinum Films Via One-Pot Liquid Crystal Templated Synthesis
    (Amer Chemical Soc, 2025) Demir, Seren; Polat, Pelin; Tertemiz, Necip Ayhan; Vural, Beyza; Babahan, Elian Melissa; Orhan, Ozan Baran; Balci, Fadime Mert
    Nanoporous platinum (NPP) thin films are crucial for applications in electrocatalysis, fuel cells, nanophotonics, and gas sensing. Conventional fabrication methods, such as dealloying, often leave residual elements that degrade the performance of the NPP thin films in applications such as electrocatalysis. In this study, for the first time, we introduce a novel method to fabricate ultrapure, flexible, large-area NPP thin films through a one-pot, liquid crystal-templated synthesis. A hexagonal lyotropic liquid crystal (LLC) phase, composed of a strong acid, a nonionic surfactant, water, and hexachloroplatinic acid, serves as a template. The LLC films, prepared with hexachloroplatinic acid concentrations of 0.1-0.5 M, exhibit distinct optical textures under a polarizing optical microscope and display low-angle diffraction patterns when analyzed with an X-ray diffractometer. Calcination at 450 degrees C yields ultrapure, conductive, and black colored NPP films. Importantly, we fabricate freestanding NPP thin films and successfully transfer them onto both rigid and flexible substrates. Bending tests reveal that a four-layer flexible NPP film having a thickness of around similar to 174 nm maintains a stable sheet resistance (similar to 30 ohm/sq) after several hundred bend cycles (1000 cycles). These findings highlight the potential of ultrapure NPP films with high nanopore and ligament density for applications in electrocatalysis, fuel cells, gas sensors, broadband absorbers, bioelectronics, and flexible electronics.
  • Article
    Durable ZrB2–ZrC Composite Materials as Advanced Electrodes for High-Performance Supercapacitors
    (Amer Chemical Soc, 2025) Paksoy, Aybike; Gungor, Ahmet; Yildirim, Ipek Deniz; Arabi, Seyedehnegar; Erdem, Emre; Balci-Cagiran, Ozge
    Boride and carbide-based materials attract increasing attention as promising options for energy storage applications. This research focuses on synthesizing pure boride and carbide compounds of zirconium (ZrB2 and ZrC) and their composite powders using mechanical activation-assisted route and subsequent heating processes. The chemical and microstructural characterization results indicate that the synthesized composite powders are of high purity, possess submicron-scale particle sizes (below 400 nm), and exhibit a high surface area of up to 9.41 m2/g. Supercapacitor devices, using the resulting powders as symmetrical electrodes, exhibit high energy density values ranging from 5.8 to 8.8 Wh/kg. The ZrB2-15 wt % ZrC composite sample achieves the highest power density at 155 W/kg, compared to 118 W/kg for the pure ZrB2 sample. Cycling tests demonstrate exceptional capacitance retention (99.4-99.9%) and cyclic stability, even after 5000 cycles, highlighting the high durability of the composite samples. These findings show that ZrB2-ZrC composites exhibit high energy and power density values and excellent cycling performance, making them strong candidates for use in high-performance supercapacitor devices.