Analysis of line-width effects in the electron spin resonance spectra of monoprotonated semiquinones

1969 ◽  
Vol 47 (2) ◽  
pp. 331-337 ◽  
Author(s):  
T. E. Gough
Keyword(s):  
Electron Spin Resonance ◽  
Line Width ◽  
Electron Spin ◽  
Energy Of Activation ◽  
Hydroxyl Group ◽  
Restricted Rotation ◽  
Spin Resonance

Electron spin resonance spectra of monoprotonated p-benzosemiquinone, 2:6-dimethyl-p-benzosemiquinone, and durosemiquinone dissolved in tetrahydrofuran at −70 °C are reported. Under such conditions restricted rotation of the hydroxyl group causes the ring positions meta to the site of protonation to appear as non-equivalent, though this effect is not observed for monoprotonated durosemiquinone. The spectra of monoprotonated p-benzosemiquinone in tetrahydrofuran exhibit both anisotropic and alternating line-width trends; equations are presented which allow the separation of these two effects and the determination of the energy of activation for the rotation of the hydroxyl group as between 31 and 40 kJ/mole. Spectra of monoprotonated 2:3- and 2:5-dimethyl-p-benzosemiquinones in 1:2 dimethoxyethane at 20 °C are also reported.

Determination of the Rates of Ring-Closure of Oxygen-Containing Analogs of Hex-5-Enyl Radical by Kinetic Electron Spin Resonance Spectroscopy

1987 ◽  
Vol 40 (1) ◽  
pp. 157 ◽  
Author(s):  
ALJ Beckwith ◽  
SA Glover
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Activation Parameters ◽  
Ring Closure ◽  
Electron Spin Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Restricted Rotation ◽  
Conformational Effects ◽  
Spin Resonance

The hex-5-enyl (1), 3-oxahex-5-enyl (6), 2-oxahex-5-enyl (9) and 2,2-dimethylbut-3- enoyloxymethyl (13) radicals have been generated by interaction of the corresponding bromides with trialkyltin or trialkylgermanium radicals, and their rate constants and activation parameters for cyclization have been determined by kinetic e.s.r . spectroscopy. The 3-oxa species (6) undergo 1,5-ring closure more rapidly than does hex-5-enyl radical (1) because of favourable stereoelectronic factors. Spectral evidence has been obtained for restricted rotation about the O-CH2* bond in the 2-oxa radical (9) as a consequence of which its ring closure is relatively slow. Similarly, 1,5-ring closure of the ester derived radical (13) is slow because of unfavourable conformational effects arising from restricted rotation about the CO-O bond. The radical (22) formed from allyl bromoacetate does not undergo ring closure. Spectral data have been obtained for various radicals (16), (19), (23), (24) formed by intermolecular addition.

Electron-spin-resonance determination of the internal field within the superconductorYBa2Cu3O7

1990 ◽  
Vol 41 (4) ◽  
pp. 2046-2048 ◽  
Author(s):  
Horacio A. Farach ◽  
Eduardo Quagliata ◽  
Taha Mzoughi ◽  
Manuel A. Mesa ◽  
Charles P. Poole ◽  
...  
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Internal Field ◽  
Spin Resonance

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.

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