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Article Citation - WoS: 58Two-Dimensional Fluorinated Boron Sheets: Mechanical, Electronic, and Thermal Properties(Amer Chemical Soc, 2018) Pekoz, Rengin; Konuk, Mine; Kilic, M. Emin; Durgun, EnginThe synthesis of atomically thin boron sheets on a silver substrate opened a new area in the field of two-dimensional systems. Similar to hydrogenated and halogenated graphene, the uniform coating of borophene with fluorine atoms can lead to new derivatives of borophene with novel properties. In this respect, we explore the possible structures of fluorinated borophene for varying levels of coverage (BnF) by using first-principles methods. Following the structural optimizations, phonon spectrum analysis and ab initio molecular dynamics simulations are performed to reveal the stability of the obtained structures. Our results indicate that while fully fluorinated borophene (BF) cannot be obtained, stable configurations with lower coverage levels (B4F and B2F) can be attained. Unveiling the stable structures, we explore the mechanical, electronic, and thermal properties of (BnF). Fluorination significantly alters the mechanical properties of the system, and remarkable results, including direction-dependent variation of Young's modulus and a switch from a negative to positive Poisson's ratio, are obtained. However, the metallic character is preserved for low coverage levels, and metal to semiconductor transition is obtained for B2F. The heat capacity at a low temperature increases with an increasing F atom amount but converges to the same limiting value at high temperatures. The enhanced stability and unique properties of fluorinated borophene make it a promising material for various high-technology applications in reduced dimensions.Article Citation - WoS: 19Citation - Scopus: 18Deviations From Born-Oppenheimer Theory in Structural Chemistry: Jahn-Teller, Pseudo Jahn-Teller, and Hidden Pseudo Jahn-Teller Effects in C3h3< and C3h3<(Amer Chemical Soc, 2013) Kayi, H.; Garcia-Fernandez, P.; Bersuker, I. B.; Boggs, J. E.The electronic structure and vibronic coupling in two similar molecular systems, radical C3H3 and anion C3H3-, in ground and excited states, are investigated in detail to show how their equilibrium structures, in deviation from the Born-Oppenheimer approximation, originate from the vibronic mixing of at least two electronic states, producing the Jahn-Teller UT), pseudo JT (PJT), and hidden PJT effects. Starting with the high-symmetry geometry D3h of C3H3, we evaluated its 2-fold degenerate ground electronic state 2E" and two lowest excited states 2A,' and 2E' and found that all of them contribute to the distortion of the ground state via the JT vibronic coupling problem E" e' and two PJT problems (E" + A(1)') circle star e" and (E" + E') circle times (a2" + e"); all the three active normal modes e'(1335 e"(1030 cm(-1)), and a2"(778 cm(-1)) are imaginary, meaning that all the three vibronic couplings are sufficiently strong to cause instability, albeit in different directions. The first of them, the ground state JT effect, enhances one of the C-C bonds (toward an ethylenic form with C-2v symmetry), while the two PJT effects produce, respectively, cis (a(2)" toward C-3v symmetry) and trans (e") puckering of the hydrogen atoms. As a result, C3H3 has two coexisting equilibrium configurations with different geometry. In the C3H3- anion, the ground electronic state in DA symmetry is an orbitally nondegenerate spin triplet (3)A(2)' with a group of close in energy singlet and triplet excited states in the order of (1)A(1),', (3)A(1)', E-1", E-3", and E-1'. This shows that two PJT couplings, (3A(2)' + (3)A(1)") circle times a(2)" and (3A2' + 3E") e", may influence the geometry of the equilibrium structure in the 3A2' state. Indeed, both vibrational modes, a(2)"(1034 cm(-1)) and e"(1284 cm(-1)), are imaginary in this state. Similar to the radical case, they produce, respectively, cis (a(2)") and trans (e") puckering of the hydrogen atoms, but no e' distortion of the basic C-3 triangle; the equilibrium configuration with Cs symmetry occurs along the stronger e" distortions. Another higher-in-energy triplet-state minimum with C-2v symmetry emerges as a result of a strong JTE in the excited 3E" electronic state. In addition to these APES minima with spin-triplet electronic states, the system has a coexisting minimum with a spin-singlet electronic state, which is shown to be due to the hidden PJT effect that couples two singlet excited states. The two lowest equilibrium configurations of the C3H3- anion with different geometry and spin realize a (common to all electronic e(2) configurations) magnetic and structural bistability accompanied by a spin crossover. Some general spectroscopic consequences are also noted. As a whole, this article is intended to demonstrate the efficiency of the vibronic coupling approach in rationalizing the origin of complicated structural features of molecular systems as due to a combination of nonadiabatic JT effects.Article Citation - WoS: 7Citation - Scopus: 7Dft Insights Into Noble Gold-Based Compound Li5aup2: Effect of Pressure on Physical Properties(Amer Chemical Soc, 2023) Surucu, Gokhan; Gencer, Aysenur; Surucu, Ozge; Ali, Md. AshrafIn this study, the Li5AuP2 compound is investigated in detail due to the unique chemical properties of gold that are different from other metals. Pressure is applied to the compound from 0 to 25 GPa to reveal its structural, mechanical, electronic, and dynamical properties using density functional theory (DFT). Within this pressure range, the compound is optimized with a tetragonal crystal structure, making it mechanically and dynam-ically stable above 18 GPa and resulting in an increment of bulk, shear, and Young's moduli of Li5AuP2. Pressure application, furthermore, changes the brittle or ductile nature of the compound. The anisotropic elastic and sound wave velocities are visualized in three dimensions. The thermal properties of the Li5AuP2 compound are obtained, including enthalpy, free energy, entropy x T, heat capacity, and Debye temperature. The electronic properties of the Li5AuP2 compound are studied using the Perdew-Burke-Ernzerhof (PBE) and Heyd-Scuseria-Ernzerhof (HSE) functionals. The pressure increment is found to result in higher band gap values. The Mulliken and bond overlap populations are also determined to reveal the chemical nature of this compound. The optical properties, such as dielectric functions, refractive index, and energy loss function of the Li5AuP2 compound, are established in detail. To our knowledge, this is the first attempt to study this compound in such detail, thus, making the results obtained here beneficial for future studies related to the chemistry of gold.Article Citation - WoS: 128Mnox< Pdag Alloy Nanoparticles for the Additive-Free Dehydrogenation of Formic Acid at Room Temperature(Amer Chemical Soc, 2015) Bulut, Ahmet; Yurderi, Mehmet; Karatas, Yasar; Say, Zafer; Kivrak, Hilal; Kaya, Murat; Zahmakiran, MehmetFormic acid (HCOOH) has a great potential as a safe and a convenient hydrogen carrier for fuel cell applications. However, efficient and CO-free hydrogen production through the decomposition of formic acid at low temperatures (<363 K) in the absence of additives constitutes a major challenge. Herein, we present a new heterogeneous catalyst system composed of bimetallic PdAg alloy and MnOx nanoparticles supported on amine-grafted silica facilitating the liberation of hydrogen at room temperature through the dehydrogenation of formic acid in the absence of any additives with remarkable activity (330 mol H-2 center dot mol catalyst(-1)center dot h(-1)) and selectivity (>99%) at complete conversion (>99%). Moreover this new catalytic system enables facile catalyst recovery and very high stability against agglomeration, leaching, and CO poisoning. Through a comprehensive set of structural and functional characterization experiments, mechanistic origins of the unusually high catalytic activity, selectivity, and stability of this unique catalytic system are elucidated. Current heterogeneous catalytic architecture presents itself as an excellent contender for clean hydrogen production via room-temperature additive-free dehydrogenation of formic acid for on-board hydrogen fuel cell applications.Article Citation - WoS: 4Citation - Scopus: 7Calcium Carbonate/Polydopamine Composite Nanoplatform Based on Tgf-Β Blockade for Comfortable Cancer Immunotherapy(Amer Chemical Soc, 2024) Li, Yunmeng; Wang, Deqiang; Sun, Jian; Hao, Zhaokun; Tang, Letian; Sun, Wanru; Wang, RanranCancer pain seriously reduces the quality of life of cancer patients. However, most research about cancer focuses solely on inhibiting tumor growth, neglecting the issue of cancer pain. Therefore, the development of therapeutic agents with both tumor suppression and cancer pain relief is crucial to achieve human-centered treatment. Here, the work reports curcumin (CUR) and ropivacaine (Ropi) coincorporating CaCO3/PDA nanoparticles (CaPNMCUR+Ropi) that realized efficient tumor immunotherapy and cancer pain suppression. The therapeutic efficiency and mechanism are revealed in vitro and in vivo. The results indicate that CaPNMCUR+Ropi underwent tumor microenvironment-responsive degradation and realized rapid release of calcium ions, Ropi, and CUR. The excessive intracellular calcium triggered the apoptosis of tumor cells, and the transient pain caused by the tumor injection was relieved by Ropi. Simultaneously, CUR reduced the levels of immunosuppressive factor (TGF-beta) and inflammatory factor (IL-6, IL-1 beta, and TNF-alpha) in the tumor microenvironment, thereby continuously augmenting the immune response and alleviating inflammatory pain of cancer animals. Meanwhile, the decrease of TGF-beta leads to the reduction of transient receptor potential vanilloid 1 (TRPV1) expression, thereby alleviating hyperalgesia and achieving long-lasting analgesic effects. The design of the nanosystem provides a novel idea for human-centered tumor treatment in the future.Article Citation - WoS: 25Citation - Scopus: 28Semi-Ipn Chitosan/Peg Microspheres and Films for Biomedical Applications: Characterization and Sustained Release Optimization(Amer Chemical Soc, 2012) Gunbas, Ismail Dogan; Sezer, Umran Aydemir; Iz, Sultan Gulce; Gurhan, Ismet Deliloglu; Hasirci, NesrinMicro drug carriers are one of the efficient methods for local or systemic cancer treatment. In this study, the aim was to prepare a novel semi-interpenetrated (semi-IPN) micro system by using biocompatible chitosan (CH) and polyethylene glycol (PEG). Various combinations of the systems were prepared and loaded with a model chemotherapeutic drug, methotrexate (MTX), and the effects of composition on the properties and the release behavior of microspheres were examined. Also, the mechanical and thermal properties were examined on film forms of similar compositions. Increase in cross-linking caused a decrease in particle size of CH from 144 to 91 mu m, while the addition of PEG caused an increase up to 163 mu m. Elastic modulus values of the films first increased and then decreased parallel to PEG content. In vitro studies showed faster MTX release from semi-IPN CH-PEG microspheres as compared to pure CH ones. Promising results were obtained in the development of biodegradable drug vehicles.Article Citation - WoS: 1Citation - Scopus: 1Penta-Graphene/SnS2 Heterostructures with Z-Scheme Charge Transfer for Efficient Photocatalytic Water Splitting(Amer Chemical Soc, 2025) Nasoz, Duygu Lale; Surucu, Ozge; Wang, Xiaotian; Surucu, Gokhan; Sarac, Yasemin; Gencer, AysenurThe present study explores the photocatalytic potential of penta-graphene (PG) and SnS2 monolayers, along with their heterostructures (PG/SnS2), using Density Functional Theory (DFT). Structural analysis confirms that the PG/SnS2 heterostructure exhibits enhanced stability, efficient charge separation, and suitable band alignment. Optimized lattice parameters (3.66 & Aring; for PG and 3.88 & Aring; for SnS2) closely matched literature values, while ab initio molecular dynamics (AIMD) confirmed thermodynamic stability at 300 K. The heterostructure's band gap of 2.75 eV (HSE method) supports visible light absorption, and the band edge positions enable hydrogen and oxygen evolution reactions across pH 0 to 6. Optical analysis reveals significant visible-light absorption with an optical band gap of 1.43 eV. Additionally, this study identifies a Z-scheme charge transfer mechanism in the PG/SnS2 heterostructure, facilitated by an internal built-in electric field that drives directional charge migration, effectively enhancing electron-hole separation and suppressing recombination losses. This Z-scheme mechanism optimizes redox reactions, making PG/SnS2 a highly efficient photocatalyst for solar-driven hydrogen production. Furthermore, the effect of water solvent is investigated, and it reveals that this heterostructure is stable under water solvent, having suitable band edges for the photocatalytic water splitting. These findings highlight the PG/SnS2 heterostructure as a promising candidate for sustainable hydrogen generation, offering a new perspective for the design of next-generation 2D photocatalytic materials.Article Citation - WoS: 4Citation - Scopus: 3Exploring the Thermal Stability of Sb2se3 for Potential Applications Through Advanced Thermal Analysis Methods(Amer Chemical Soc, 2025) Altuntas, Gozde; Isik, Mehmet; Surucu, Gokhan; Parlak, Mehmet; Surucu, OzgeAntimony selenide (Sb2Se3) is a promising material for energy applications, including photovoltaics, thermoelectrics, and photodetectors, due to its favorable electronic properties, availability, and low toxicity. However, its thermal stability, crucial for device efficiency and reliability, has been less explored, leaving a gap in understanding its high-temperature suitability. This study evaluates the thermal stability of Sb2Se3 using thermogravimetric analysis (TGA), differential thermal analysis (DTA), and differential scanning calorimetry (DSC). The results show that Sb2Se3 remains stable up to 500 degrees C, with two significant weight loss stages: 1.75% between 500 and 610 degrees C, and 3.50% between 610 and 775 degrees C, indicating decomposition processes. Activation energies for the decomposition phases were determined as 121.8 and 57.2 kJ/mol using the Coats-Redfern method. Additionally, an endothermic phase transition was observed between 599 and 630.6 degrees C via DSC analysis. These findings demonstrate Sb2Se3's potential for high-temperature energy applications, providing essential insights for optimizing its use in solar cells, thermoelectric devices, and other technologies.Article Citation - WoS: 24Citation - Scopus: 23Revealing the Effects of Defect States on the Nonlinear Absorption Properties of the Tlinsse and Tl2in2< Crystals in Near-Infrared Optical Limiting Applications(Amer Chemical Soc, 2024) Dogan, Anil; Karatay, Ahmet; Isik, Mehmet; Yildiz, Elif Akhuseyin; Gasanly, Nizami Mamed; Elmali, AyhanThe present study represents the effect of defect states on the nonlinear absorption and optical limiting performances of TlInSSe and Tl2In2S3Se single crystals with near-infrared excitations. The band gap energies were 2.2 and 2.22 eV, and the Urbach energies were 0.049 and 0.034 eV for TlInSSe and Tl2In2S3Se, respectively. The trapping time of localized defect states was found to be 8 ns by femtosecond transient absorption measurements. The analysis of open-aperture Z-scan data depends on two different fitting models to determine the effect of defect states on the nonlinear absorption (NA) properties of the studied crystals. Model 1 only considers two-photon absorption (TPA), while model 2 includes one-photon absorption (OPA), TPA, and free carrier absorption (FCA). The NA coefficients (ss(eff)) obtained from model 2 are higher than the values (ss) obtained from model 1 at the same intensities, revealing that defect states contribute to NA through OPA. The optical limiting properties of the TlInSSe and Tl2In2S3Se crystals were examined under 1064 nm wavelength excitation. The limiting thresholds were found to be 1.16 and 0.27 mJ/cm(2) at 29.8 GW/m(2) and 99.5 GW/m(2) input intensities, respectively. The results show that TlInSSe and Tl2In2S3Se crystals have promising potential for near-infrared optical limiting applications.Article Citation - WoS: 24Citation - Scopus: 24Light-Induced Paramagnetism in Colloidal Ag+-doped Cdse Nanoplatelets(Amer Chemical Soc, 2021) Najafi, Arman; Sharma, Manoj; Delikanli, Savas; Bhattacharya, Arinjoy; Murphy, Joseph R.; Pientka, James; Petrou, AthosWe describe a study of the magneto-optical properties of Ag+-doped CdSe colloidal nanoplatelets (NPLs) that were grown using a novel doping technique. In this work, we used magnetic circularly polarized luminescence and magnetic circular dichroism spectroscopy to study light-induced magnetism for the first time in 2D solution-processed structures doped with nominally nonmagnetic Ag+ impurities. The excitonic circular polarization (P-X) and the exciton Zeeman splitting (Delta E-Z) were recorded as a function of the magnetic field (B) and temperature (T). Both Delta E-Z and P-X have a Brillouin-function-like dependence on B and T, verifying the presence of paramagnetism in Ag+-doped CdSe NPLs. The observed light-induced magnetism is attributed to the transformation of nonmagnetic Ag+ ions into Ag2+, which have a nonzero magnetic moment. This work points to the possibility of incorporating these nanoplatelets into spintronic devices, in which light can be used to control the spin injection.
