Magnetic Defects in Transitional Metal Di-Chalcogenide Semiconducting Layers

MRS Advances ◽  
2018 ◽  
Vol 3 (6-7) ◽  
pp. 351-357 ◽  
Author(s):  
L. M. Martinez ◽  
M. D. Teran ◽  
R. R. Chianelli ◽  
S. R. J. Hennadige ◽  
S. R. Singamaneni
Keyword(s):  
Electron Spin ◽  
Esr Spectra ◽  
Oxygen Species ◽  
Temperature Dependent ◽  
Paramagnetic Defect ◽  
Adsorbed Oxygen Species ◽  
Transitional Metal ◽  
Spin Resonance ◽  
Two Dimensional Materials ◽  
Spin Species

ABSTRACTIn this work, we report on the electron spin resonance (ESR) studies performed on few-layered nanocrystalline (NCs) MoS2, WS2, and TiS2 prepared using hydrothermal and vapor transport methods. From the temperature dependent ESR spectra collected from MoS2 NCs, we have identified adsorbed oxygen species, sulphur vacancies, thio- and oxo-Mo5+ related paramagnetic defect centers. WS2 NCs have exhibited W+3 and oxo-W+5 paramagnetic defect spin species. TiS2 NCs showed defects such as Fe3+ (unwanted), oxygen and sulfur vacancies. This work demonstrates the usage of spin-sensitive spectroscopy such as ESR in unravelling the defects which contain unpaired electron spin centers in layered NCs two-dimensional materials.

Computer Simulation of Electron Spin Resonance Spectra of Ge25S75and Ge30S70 Bulk Glasses

1997 ◽  
Vol 62 (11) ◽  
pp. 1721-1729
Author(s):  
Zdeněk Černošek ◽  
Marek Liška ◽  
Peter Pelikán ◽  
Eva Černošková ◽  
Marián Valko ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Liquid Nitrogen Temperature ◽  
Esr Spectra ◽  
Dangling Bond ◽  
Paramagnetic Defect ◽  
Bond Model ◽  
Spin Resonance ◽  
Bulk Glasses ◽  
Good Agreement

The electron spin resonance (ESR) spectra of bulk glasses of the chemical composition Ge25S75 and Ge30S70 were measured at liquid nitrogen temperature and subjected to computerized separation. The complex ESR spectra of both glasses were found to represent a superposition of three paramagnetic defect spectra, two with orthorhombic tensors g and one with the axial tensor g. The former two paramagnetic centers can be related to a two-atomic defect of the sulfur-sulfur type, the latter to a germanium-sulfur defect. The experimental results are in a good agreement with the non-dangling bond model of paramagnetic defects in Ge-S glasses.

FREE RADICALS OF BIOLOGICAL INTEREST: PART II. ELECTRON SPIN RESONANCE (ESR) SPECTRA OF 2537 A IRRADIATED AMINO ACIDS

1967 ◽  
Vol 45 (12) ◽  
pp. 1831-1839 ◽  
Author(s):  
W. F. Forbes ◽  
P. D. Sullivan
Keyword(s):  
Amino Acids ◽  
Electron Spin Resonance ◽  
Electron Spin ◽  
Hydrogen Abstraction ◽  
Esr Spectra ◽  
Side Chain ◽  
Biological Interest ◽  
Spin Resonance ◽  
Cyclohexadienyl Radical ◽  
Secondary Radical

Polycrystalline amino acids, when irradiated with 2537 Å light, afford a variety of electron spin resonance signals. These signals are generally stable at room temperature for relatively long periods of time. For a number of the spectra obtained, there is evidence that more than one radical species contributes to the observed spectra. The signals obtained frequently differ from those obtained on exposure to ionizing radiation. The postulated species formed can often be visualized as being formed by effective hydrogen abstraction from the alkyl-substituted tertiary carbon atom or from the —OH, —SH or —NH group contained in the side chain. For L-phenylalanine a secondary radical is obtained, which is ascribed to a cyclohexadienyl radical.

Electron spin resonance observations of photochemically generated contact ammonium ion-pairs of fluoro-substituted ketones

1979 ◽  
Vol 57 (5) ◽  
pp. 600-602 ◽  
Author(s):  
K. S. Chen ◽  
T. Foster ◽  
J. K. S. Wan
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Ion Pairs ◽  
Esr Spectra ◽  
Ammonium Ion ◽  
Spin Resonance ◽  
Photochemical Systems

Contact radical ion-pairs of ammonium and fluoro-substituted ketones were generated in photochemical systems and their here-to-fore elusive esr spectra were characterized.

Electron Spin Resonance Investigations on Perovskite Solar Cell Materials Deposited on Glass Substrate

MRS Advances ◽  
2018 ◽  
Vol 3 (32) ◽  
pp. 1831-1836
Author(s):  
C. L. Saiz ◽  
E. Castro ◽  
L. M. Martinez ◽  
S. R. J. Hennadige ◽  
L. Echegoyen ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Solar Cell ◽  
Line Width ◽  
Electron Spin ◽  
Glass Substrate ◽  
Esr Spectra ◽  
Perovskite Solar Cell ◽  
Hole Transport ◽  
Ex Situ ◽  
Spin Resonance

ABSRTACTIn this article, we report low-temperature electron spin resonance (ESR) investigations carried out on solution processed three-layer inverted solar cell structures: PC61BM/CH3NH3PbI3/PEDOT:PSS/Glass, where PC61BM and PEDOT:PSS act as electron and hole transport layers, respectively. ESR measurements were conducted on ex-situ light (1 Sun) illuminated samples. We find two distinct ESR spectra. First ESR spectra resembles a typical powder pattern, associated with gx = gy = 4.2; gz = 9.2, found to be originated from Fe3+ extrinsic impurity located in the glass substrate. Second ESR spectra contains a broad (peak-to-peak line width ∼ 10 G) and intense ESR signal appearing at g = 2.008; and a weak, partly overlapped, but much narrower (peak-to-peak line width ∼ 4 G) ESR signal at g = 2.0022. Both sets of ESR spectra degrade in intensity upon light illumination. The latter two signals were found to stem from light-induced silicon dangling bonds and oxygen vacancies, respectively. Our controlled measurements confirm that these centers were generated during UV-ozone treatment of the glass substrate –a necessary step to be performed before PEDOT:PSS is spin coated. This work forms a significant step in understanding the light-induced- as well as extrinsic defects in perovskite solar cell materials.

Microscopic Study of Metal Hydrides using Electron Spin resonance

1980 ◽  
Vol 3 ◽  
Author(s):  
E. L. Venturini
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Metal Hydrides ◽  
Esr Spectra ◽  
Spectroscopic Technique ◽  
Host Lattice ◽  
Hydrogen Ions ◽  
Spin Resonance ◽  
Symmetry Phase ◽  
Paramagnetic Ions

ABSTRACTElectron spin resonance (ESR) of dilute paramagnetic ions in nonmagnetic metallic hydrides provides microscopic information about the hydrogen ions in the immediate vicinity of the impurity. By comparing ESR spectra for different host metals and several hydrogen/metal ratios, one can determine material properties including host lattice symmetry, phase boundaries and occupation of available sites by hydrogen. Examples are presented of ESR of dilute Er in group IIIB and IVB metal hydrides, demonstrating the sensitivity and versatility of ESR as a spectroscopic technique.

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