Charge carrier recombination in amorphous organic semiconductors
- Authors: Novikov S.А.1,2
-
Affiliations:
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS
- National Research University Higher School of Economics
- Issue: Vol 60, No 11 (2024): Special issue “Electrochemistry-2023”, part 2
- Pages: 783-792
- Section: Articles by participants of the All-Russian Conference “Electrochemistry-2023” (Moscow, October 23–26, 2023)
- URL: https://snv63.ru/0424-8570/article/view/682802
- DOI: https://doi.org/10.31857/S0424857024110049
- EDN: https://elibrary.ru/NPOBJZ
- ID: 682802
Cite item
Abstract
Bimolecular recombination of charge carriers in amorphous organic semiconductors is considered. A common feature of these materials is the spatial correlation of the random energy landscape in which hopping transport of charge carriers occurs. The recombination rate constant for such materials was calculated including the case of locally ordered materials. It turns out that the spatial correlation of the random landscape causes violation of the Langevin relation between mobilities of charge carriers and the recombination rate constant. For different sources of energetic disorder the true rate constant can be either less or greater than the corresponding Langevin value. Promising classes of organic semiconductors are indicated where the recombination rate constant can exceed the Langevin value, leading to a potential increase in the efficiency of light generation in organic light-emitting diodes. Organic semiconductors with low recombination constants are promising for the use in solar cells. Features of two-dimensional bimolecular recombination in materials based on oligo- and polythiophenes, in which two-dimensional lamellae are formed, are considered. The formal recombination rate constant becomes dependent on the carrier concentration and effect of spatially correlated energetic disorder leads to the development of various rate constant dependences on the carrier concentration. Analysis of the current-voltage characteristics of organic devices gives the possibility to distinguish between two-dimensional and three-dimensional recombination.
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About the authors
S. А. Novikov
A.N. Frumkin Institute of Physical Chemistry and Electrochemistry RAS; National Research University Higher School of Economics
Author for correspondence.
Email: novikov@elchem.ac.ru
Russian Federation, Moscow; Moscow
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Supplementary files

Note
The article was presented by a participant in the All-Russian Conference “Electrochemistry-2023”, held from October 23 to October 26, 2023 in Moscow at the Institute of Physical Chemistry and Electrochemistry named after A.N. Frumkin RAS.