Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Citation - WoS: 1Citation - Scopus: 1Phase-Separated Amorphous Si2BN: A Computational Study(AIP Publishing, 2025-02-11) Durandurdu, MuratThis study investigates the atomic structure, bonding, and electrical and mechanical properties of amorphous silicon boron nitride (a-Si2BN) using ab initio molecular dynamics simulations. The simulations reveal a distinct phase-separated structure comprising Si-rich and BN-rich domains. BN layers are embedded within the amorphous Si matrix, with only a few bridging atoms linking these regions. The Si-rich region exhibits topological similarities to amorphous silicon, albeit with notable structural distortions. Electronic structure calculations indicate semiconducting behavior with a small bandgap, while mechanical property analysis shows a moderate bulk modulus and Young's modulus, achieving a balance between rigidity and elasticity. These findings position a-Si2BN as a promising material for advanced applications, including flexible electronics, high-temperature semiconductors, and energy storage devices. While the proposed structure is currently hypothetical, its potential experimental realization could open new avenues in material design for emerging technologies.Article Citation - WoS: 12Citation - Scopus: 11Long-Time Stable Colloidal Zn-Ag Quantum Dots With Tunable Midgap-Involved Emission(AIP Publishing, 2021-02-11) Sabzevari, Zahra; Sahraei, Reza; Jawhar, Nawzad Nadhim; Yazici, Ahmet Faruk; Mutlugun, Evren; Soheyli, EhsanQuaternary Zn-Ag-In-S (ZAIS) quantum dots (QDs) with efficient, tunable, and stable photoluminescence (PL) emission were prepared via a simple, effective, and low-cost reflux method. The structural analysis revealed the dominance of the quantum confinement effect. The calculated PL emission quantum yield was enhanced from 8.2% to 28.7% with experimental parameters indicating their marked influence on the PL emission properties of the final product. Particularly, it was found that by varying the precursors' feeding ratio, tunable emission from green to red was achieved. A set of direct and indirect pieces of evidence such as the broad-band emission spectrum (FWHM>100nm), large Stokes shift more than 120nm, and predominantly a biexponentially long-lived decay profile with an average lifetime of about 366ns were observed, showing the contribution of midgap localized energy levels in the recombination process. These data were obtained independently on the experimental condition used, which confirmed that this is mostly an intrinsic electronic property of quaternary In-based QDs. Finally, to ensure the stability of QDs in terms of colloidal and optical emission, their emission ability was evaluated after 26 months of storage. Colloidal QDs were still luminescent with strong yellowish-orange color with emission efficiency of similar to 20.3% after 26 months. The combination of synthesis simplicity, compositional non-toxicity, PL emission superiority (strong, tunable, stable, and long lifetime emission), and colloidal stabilities confirms that the present ZAIS QDs are promising candidates for a wide range of applications in biomedicine, anticounterfeiting, and optoelectronics.Article Citation - WoS: 55Citation - Scopus: 57Bond Energies of ThO+ and ThC+: A Guided Ion Beam and Quantum Chemical Investigation of the Reactions of Thorium Cation With O2 and CO(AIP Publishing, 2016-05-13) Cox, Richard M.; Citir, Murat; Armentrout, P. B.; Battey, Samuel R.; Peterson, Kirk A.Kinetic energy dependent reactions of Th+ with O-2 and CO are studied using a guided ion beam tandem mass spectrometer. The formation of ThO+ in the reaction of Th+ with O-2 is observed to be exothermic and barrierless with a reaction efficiency at low energies of k/k(LGS) = 1.21 +/- 0.24 similar to the efficiency observed in ion cyclotron resonance experiments. Formation of ThO+ and ThC+ in the reaction of Th+ with CO is endothermic in both cases. The kinetic energy dependent cross sections for formation of these product ions were evaluated to determine 0 K bond dissociation energies (BDEs) of D-0(Th+-O) = 8.57 +/- 0.14 eV and D-0(Th+-C) = 4.82 +/- 0.29 eV. The present value of D-0(Th+-O) is within experimental uncertainty of previously reported experimental values, whereas this is the first report of D-0(Th+-C). Both BDEs are observed to be larger than those of their transition metal congeners, TiL+, ZrL+, and HfL+ (L = O and C), believed to be a result of lanthanide contraction. Additionally, the reactions were explored by quantum chemical calculations, including a full Feller-Peterson-Dixon composite approach with correlation contributions up to coupled-cluster singles and doubles with iterative triples and quadruples (CCSDTQ) for ThC, ThC+, ThO, and ThO+, as well as more approximate CCSD with perturbative (triples) [CCSD(T)] calculations where a semi-empirical model was used to estimate spin-orbit energy contributions. Finally, the ThO+ BDE is compared to other actinide (An) oxide cation BDEs and a simple model utilizing An(+) promotion energies to the reactive state is used to estimate AnO(+) and AnC(+) BDEs. For AnO(+), this model yields predictions that are typically within experimental uncertainty and performs better than density functional theory calculations presented previously. Published by AIP Publishing.