Configuration of Electron Transfer Components Studied by EPR Spectroscopy

Bittl, Robert; Kawamori, Asako

doi:10.1007/1-4020-4254-x_18

Cited by 6 publications

(9 citation statements)

References 75 publications

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“…Therefore, EPR spectroscopy has extensively been used in the research of photosynthesis and molecular donor-acceptor systems where light-induced electron transfer processes and recombination reactions take place. [64][65][66][67][68][69][70][71] EPR at various frequencies allowed the spectral separation of distinct radicals as well as the determination of g-tensors and hyperfine tensors. Advanced pulsed methods provided insight into hyperfine interactions and relaxation phenomena.…”

Section: Bhj Materials Complementary Pulsed Epr Techniques Like Elementioning

confidence: 99%

“…EPR spectroscopy has extensively been used in the research of photochemical transformations as a valuable method for studying time-dependent charge and spin dynamics. [64][65][66][67][68][69][70][71]125] The time resolution of EPR is much lower than ultrafast optical techniques. The conventional X-band EPR operates at 9-10 GHz frequency with a typical time-response of 100s of ns (see Introduction).…”

Section: Time-resolved Epr Studies Of Charge Transfer Dynamicsmentioning

confidence: 99%

“…[72] The tr-EPR techniques were crucial for understanding spin-dependent photoinduced energy and charge transfer pathways in molecular donor-acceptor systems and photosynthesis. [64][65][66][67][68]70,72,125,[143][144][145][146] The analysis of the tr-EPR spectra and kinetics for the study of charge separation dynamics in OPVs clearly demonstrates the similarity of these processes with those in photosynthetic proteins and donor-acceptor assemblies. A general schematic of typical pathways for sequential photoinduced charge separation process in donor-acceptor systems is shown in Figure 14.…”

Section: Time-resolved Cw and Pulsed Epr Studies Of Ct-statesmentioning

confidence: 99%

“…[150][151][152][153] These types of spectra are commonly detected in molecular donor-acceptor assemblies and in photosynthetic systems, such as photosystems of plants and bacteria. [67][68]70,125,143,145,[154][155] Thus, the tr-EPR spectra recorded in a P3HT:PC 61 BM blend were compared to that observed in photosystem I (Figure 16). [151] Both spectra demonstrate EAEA polarization pattern as well as a similar width of the spectra, ca.…”

Section: Time-resolved Cw and Pulsed Epr Studies Of Ct-statesmentioning

confidence: 99%

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Charge Transfer Processes in OPV Materials as Revealed by EPR Spectroscopy

Niklas

Poluektov

2017

Advanced Energy Materials

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Understanding charge separation and charge transport at a molecular level is crucial for improving the efficiency of organic photovoltaic (OPV) cells. Under illumination of Bulk Heterojunction (BHJ) blends of polymers and fullerenes, various paramagnetic species are formed including polymer and fullerene radicals, radical pairs, and photoexcited triplet states. Light-induced Electron Paramagnetic Resonance (EPR) spectroscopy is ideally suited to study these states in BHJ due to its selectivity in probing the paramagnetic intermediates. Advanced techniques like pulsed EPR and ENDOR spectroscopy allow the determination of hyperfine coupling tensors, while high-frequency EPR allows the EPR signals of the individual species to be resolved and their g-tensors to be determined. The magnetic resonance parameters of the various polymer donors reveal details about the delocalization of the positive polaron which is important for the efficient charge separation in BHJ systems. Time-resolved EPR can contribute to the study of the dynamics of charge separation, charge transfer and recombination in BHJ by probing the unique spectral signatures of charge transfer and triplet states. EPR also has the potential to allow characterization of intermediates and products of BHJ degradation.

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Section: Bhj Materials Complementary Pulsed Epr Techniques Like Elementioning

confidence: 99%

Section: Time-resolved Epr Studies Of Charge Transfer Dynamicsmentioning

confidence: 99%

Section: Time-resolved Cw and Pulsed Epr Studies Of Ct-statesmentioning

confidence: 99%

Section: Time-resolved Cw and Pulsed Epr Studies Of Ct-statesmentioning

confidence: 99%

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Charge Transfer Processes in OPV Materials as Revealed by EPR Spectroscopy

Niklas

Poluektov

2017

Advanced Energy Materials

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“…The laboratory of Bittl analysed PELDOR measurements between an iron-sulfur cluster and a nickel-iron centre in the hydrogenase from Desulfovibrio vulgaris Miyazaki F taking the spin projection factors for the individual iron centres in the cluster into account [104]. Already in the last century, Kawamori's laboratory did PELDOR measurements involving the manganese cluster in PSII in its S = 1 / 2 state [105,106]. The laboratory of Goldfarb is the first who successfully performed PELDOR measurements on a high-spin metal centre, a gadolinium(III) complex [107].…”

Section: Metal Ionsmentioning

confidence: 99%

Pulsed electron–electron double resonance: beyond nanometre distance measurements on biomacromolecules

Reginsson

Schiemann

2011

Biochemical Journal

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PELDOR (or DEER; pulsed electron-electron double resonance) is an EPR (electron paramagnetic resonance) method that measures via the dipolar electron-electron coupling distances in the nanometre range, currently 1.5-8 nm, with high precision and reliability. Depending on the quality of the data, the error can be as small as 0.1 nm. Beyond mere mean distances, PELDOR yields distance distributions, which provide access to conformational distributions and dynamics. It can also be used to count the number of monomers in a complex and allows determination of the orientations of spin centres with respect to each other. If, in addition to the dipolar through-space coupling, a through-bond exchange coupling mechanism contributes to the overall coupling both mechanisms can be separated and quantified. Over the last 10 years PELDOR has emerged as a powerful new biophysical method without size restriction to the biomolecule to be studied, and has been applied to a large variety of nucleic acids as well as proteins and protein complexes in solution or within membranes. Small nitroxide spin labels, paramagnetic metal ions, amino acid radicals or intrinsic clusters and cofactor radicals have been used as spin centres.

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Bibliography of reviews and methods of photosynthesis-90

Šesták

Čatský

2006

Photosynt.

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Configuration of Electron Transfer Components Studied by EPR Spectroscopy

Cited by 6 publications

References 75 publications

Charge Transfer Processes in OPV Materials as Revealed by EPR Spectroscopy

Charge Transfer Processes in OPV Materials as Revealed by EPR Spectroscopy

Pulsed electron–electron double resonance: beyond nanometre distance measurements on biomacromolecules

Bibliography of reviews and methods of photosynthesis-90

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