Geminate and non-geminate recombination in a-As2Se3

Mort, J.; Chen, I.; Morgan, M.; Grammatica, S.

doi:10.1016/0038-1098(81)90237-4

Cited by 22 publications

(4 citation statements)

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“…This discrepancy between theoretical model prediction and experimental results is not fully understood. One possible explanation is that although the photogeneration yield at a low electric field is indeed independent of the electric field strength, the drift velocity of the photogenerated charge carriers is so low that the probability of bimolecular recombination and/or trapping is high and it increases considerably with decreasing field strength. ,, The electric field dependences of the photogeneration quantum yield φ( F ) determined experimentally for PCBM+5%PMMA, PCMB+5%PS, and PCBM+5%P3HT systems are shown in Figure . For all the samples φ depends very strongly on electric field in the entire investigated range.…”

Section: Resultsmentioning

confidence: 99%

“…Theoretical models ,, and experimental investigations − of photogeneration of charge carriers in organic photoconductors show that for a low electric field the photogeneration yield has very low values that are almost independent of the electric field. However, one can find reports where a monotonical decrease of φ with declining electric field is described.…”

Section: Resultsmentioning

confidence: 99%

“…To apply the model based on Onsager’s 1938 theory of geminate recombination, one has to postulate a priori a mathematical form of radial distribution function of thermalization length g R ( r 0 ) (eqs –). With the Dirac delta distribution function it is assumed that the thermalization distance r 0M and primary photogeneration quantum yield η 0 are parameters characteristic of a particular type of photoconductor and does not depends on the electric field. ,,, An occurrence of a single, precisely defined value of r 0M can have physical meaning only when the thermalization distance is much larger than the size of a molecule. For instance, Borsenberger and Melz analyzed the charge carries photogeneration phenomenon in pristine poly( N -vinylcarbazole) (PVK) and in PVK photosensitized by the 2,4,7-trinitrofluorenone molecules.…”

Section: Discussionmentioning

confidence: 99%

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Photogeneration of Charge Carriers in (Phenyl-C61-butyric Acid Methyl Ester) Mixed with a Small Amount of Polymers

2017

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Photogeneration of charge carriers in closely packed phenyl-C61butyric acid methyl ester (PCBM) was investigated by means of the xerographic discharge technique. It was found that the position of the center of mass of the thermalized electron is positioned at a distance that is integral to the multiplicity of the center-to-center distance between the adjacent PCBM molecules. For a low electric field, 10 4 −10 7 V/m, the most photogenerated electrons originate from the electrons thermalized at the molecule next but one to the geminate recombination center. For the threshold electric field (ca. 2 × 10 8 V/m) the expected value of the thermalization length, ca. 1.9 nm, is independent of the assumed distribution functions of thermalization distance of the electron−hole pairs. The Coulomb binding energy for this characteristic of PCBM electron−hole separation length is correlated with the threshold energy value separating the extrinsic and intrinsic photogeneration in fullerenes. The model predicts the observed experimentally threshold value of photon energy 2.25 eV, below which the photogeneration yield in fullerene-based materials decreases abruptly; then, taking into account the average electron−hole pair Coulomb binding energy 0.15 eV, one can calculate the electric gap energy 2.4 eV, consistent with the literature data. It explains also how the presence of poly(3-hexylthiophene) influences the photogeneration process.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Photogeneration of Charge Carriers in (Phenyl-C61-butyric Acid Methyl Ester) Mixed with a Small Amount of Polymers

2017

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“…A number of possible explanations suggest themselves.F irst, the electric field might not be sufficient to break the electron-hole pair. However, studies of the field dependence of photogeneration in a-AsSe xerographic measurements show an increase for fields above5V/µm which when interpreted by Onsager's theory involves field-assisted exciton separation [10]. Regardless of whether the mechanism is Onsager-like or not, the increase indicates that geminate electron-hole pairs must be separating.…”

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confidence: 93%

Photoinduced dichroism and the lack of a field effect

Johanson

Kowalyshyn

Kasap

2011

Phys. Status Solidi C

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The phenomenon of photoinduced dichroism in chalcogenide glasses requires a structural rearrangement of atoms in the localized region where the photon is absorbed. The structural change is facilitated by the energy released during electron‐hole recombination. The dichroism is induced because regions that preferentially absorb the incident polarization will be those that suffer the atomic rearrangements thus bleaching the material for that polarization. A strong electric field should break geminate pairs and transport the electron and hole away from the absorbing region which should quench the photoinduced dichroism. We have searched for such a field effect in glassy arsenic selenide at fields up to 10 V/μm. No decrease in the rate of induced dichroism is observed (the rate actually increases by about 10%) and no change is observed in the stretching parameter when the time dependence is fit to a stretched exponential. These results are consistent with those of other researchers who also failed to find a field effect. The implications of these results for the theory of photoinduced dichroism are discussed. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Photoinduced Optical Absorption in Glassy As2Se3

Monroe

Kastner

1985

Physics of Disordered Materials

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Geminate and non-geminate recombination in a-As2Se3

Cited by 22 publications

References 11 publications

Photogeneration of Charge Carriers in (Phenyl-C61-butyric Acid Methyl Ester) Mixed with a Small Amount of Polymers

Photogeneration of Charge Carriers in (Phenyl-C61-butyric Acid Methyl Ester) Mixed with a Small Amount of Polymers

Photoinduced dichroism and the lack of a field effect

Photoinduced Optical Absorption in Glassy As2Se3

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