Browsing by Subject "Boron"

Now showing 1 - 6 of 6

Open Access
Bias in bonding behavior among boron, carbon, and nitrogen atoms in ion implanted a-BN, a-BC, and diamond like carbon films
(2011) Genisel, M. F.; Uddin, M. N.; Say, Z.; Kulakci, M.; Turan, R.; Gulseren, O.; Bengu, E.
In this study, we implanted Nþ and Nþ 2 ions into sputter deposited amorphous boron carbide (a-BC) and diamond like carbon (DLC) thin films in an effort to understand the chemical bonding involved and investigate possible phase separation routes in boron carbon nitride (BCN) films. In addition, we investigated the effect of implanted Cþ ions in sputter deposited amorphous boron nitride (a-BN) films. Implanted ion energies for all ion species were set at 40 KeV. Implanted films were then analyzed using x-ray photoelectron spectroscopy (XPS). The changes in the chemical composition and bonding chemistry due to ion-implantation were examined at different depths of the films using sequential ion-beam etching and high resolution XPS analysis cycles. A comparative analysis has been made with the results from sputter deposited BCN films suggesting that implanted nitrogen and carbon atoms behaved very similar to nitrogen and carbon atoms in sputter deposited BCN films. We found that implanted nitrogen atoms would prefer bonding to carbon atoms in the films only if there is no boron atom in the vicinity or after all available boron atoms have been saturated with nitrogen. Implanted carbon atoms also preferred to either bond with available boron atoms or, more likely bonded with other implanted carbon atoms. These results were also supported by ab-initio density functional theory calculations which indicated that carbon-carbon bonds were energetically preferable to carbon-boron and carbon-nitrogen bonds.
Open Access
Effect of Superconductivity–Magnetism Interaction on the Differential Conductivity in Ho(NiB)2C/Ag Point Contacts
(M A I K Nauka - Interperiodica, 2002) Askerzade, I. N.; Tanatar, Bilal
In terms of the Blonder–Tinkham–Klapwjik theory, the differential conductivity of Ho(NiB)2C/Agpoint contacts is explained by the coexistence of magnetic ordering and superconductivity in holmium boroncarbides.
Open Access
One-step codoping of reduced graphene oxide using boric and nitric acid mixture and its use in metal-free electrocatalyst
(Elsevier, 2015) Tien H.N.; Kocabas, C.; Hur, S.H.
In this study, the preparation of a highly efficient metal-free electrocatalyst, boron and nitrogen codoped reduced graphene oxide (BN-rGO), with an excellent durability is reported. The BN-rGO were prepared in one step using boric and nitric acid mixture, exhibiting highly improved oxygen reduction reaction (ORR) activity than those of the pristine GO and single doped rGOs. The electrocatalyst also showed the excellent long-term durability and CO tolerance than those of the commercial Pt/C catalysts. © 2014 Elsevier B.V.All rights reserved.
Open Access
Spectroscopic evaluation of DNA–borate Interactions
(Humana Press Inc., 2015) Ozdemir, A.; Sarioglu O. F.; Tekinay, T.
We describe the binding characteristics of two natural borates (colemanite and ulexite) to calf thymus DNA by UV–vis absorbance spectroscopy, circular dichroism (CD) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and a competitive DNA binding assay. Our results suggest that colemanite and ulexite interact with calf thymus DNA under a non-intercalative mode of binding and do not alter the secondary structure of the DNA helix. The FT-IR spectroscopy results indicate that the two borates might interact with DNA through sugar-phosphate backbone binding. © 2015, Springer Science+Business Media New York.
Open Access
Synthesis of symmetrical multichromophoric bodipy dyes and their facile transformation into energy transfer cassettes
(2010) Bozdemir, O. A.; Cakmak, Y.; Sozmen F.; Ozdemir, T.; Siemiarczuk, A.; Akkaya, E. U.
Multichromophoric boron-dipyrromethene (Bodipy) dyes synthesized on phenylene-ethynylene platforms have been be converted to energy transfer cassettes in a one-step chemical transformation. Excitation energy transfer processes in these highly symmetrical derivatives were studied in detail, including time-re-solved fluorescence spectroscopy techniques. Excitation spectra and the emission lifetimes suggest efficient energy transfer between the donor and acceptor chromophore. These novel energy transfer cassettes, while highlighting a short-cut approach to similar energy transfer systems, could be useful as large pseudo-Stokes shift multichromophoric dyes with potential applications in diverse applications.
Open Access
Theoretical and spectroscopic investigations on the structure and bonding in B-C-N thin films
(2009) Bengu, E.; Genisel, M. F.; Gulseren, O.; Ovali, R.
In this study, we have synthesized boron, carbon, and nitrogen containing films using RF sputter deposition. We investigated the effects of deposition parameters on the chemical environment of boron, carbon, and nitrogen atoms inside the films. Techniques used for this purpose were grazing incidence reflectance-Fourier-transform infrared spectroscopy (GIR-FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). GIR-FTIR experiments on the B-C-N films deposited indicated presence of multiple features in the 600 to 1700 cm- 1 range for the infrared (IR) spectra. Analysis of the IR spectra, XPS and the corresponding EELS data from the films has been done in a collective manner. The results from this study suggested even under nitrogen rich synthesis conditions carbon atoms in the B-C-N films prefer to be surrounded by other carbon atoms rather than boron and/or nitrogen. Furthermore, we have observed a similar behavior in the chemistry of B-C-N films deposited with increasing substrate bias conditions. In order to better understand these results, we have compared and evaluated the relative stability of various nearest-neighbor and structural configurations of carbon atoms in a single BN sheet using DFT calculations. These calculations also indicated that structures and configurations that increase the relative amount of C-C bonding with respect to B-C and/or C-N were energetically favorable than otherwise. As a conclusion, carbon tends to phase-segregate in to carbon clusters rather than displaying a homogeneous distribution for the films deposited in this study under the deposition conditions studied.