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. 2023 Sep 7;14(35):7892-7896.
doi: 10.1021/acs.jpclett.3c02120. Epub 2023 Aug 28.

Disorder and Photogeneration Efficiency in Organic Semiconductors

Artem V Toropin  1 , Vladimir R Nikitenko  1 , Nikolai A Korolev  1 , Oleg V Prezhdo  2
Affiliations

Disorder and Photogeneration Efficiency in Organic Semiconductors

Artem V Toropin et al. J Phys Chem Lett. .

Abstract

An analytical description of the separation probability of a geminate pair in organic semiconductors is given. The initial diffusion of "hot" twins is anomalously strong due to energy disorder. This circumstance significantly increases the photogeneration quantum yield at low temperatures and weakens its temperature dependence relative to predictions of the Onsager model, in agreement with Monte Carlo and experimental results.

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Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
Scheme of separation of the geminate pair. The dashed and dash-dotted lines show the Coulomb interaction energy at the energy of hopping centers equal to 0 (the highest concentration of centers) and at the transport energy Ec, respectively.
Figure 2
Figure 2
Time dependence of the survival probability of the geminate pair for several temperatures, in Kelvin, obtained from Monte Carlo simulations. Other parameters are ε = 3.8, E0 = 0.05 eV, v0 = 1013 s–1, and formula imageformula image. t0 = exp(2γa0)/ν0 ≈ 5.46 × 10−12 s is the typical hopping time.
Figure 3
Figure 3
Comparison of Monte Carlo results (squares) and the analytical model (circles) for the temperature dependence of the separation probability (quantum yield) of the geminate pair. The dashed line shows the result of the Onsager model at r0 = ri = a0. The other parameters are the same as for Figure 2.
Figure 4
Figure 4
Same as in Figure 3, but in the case of a small typical jump length and strong localization. t0 = 2.2 × 10–9 s. The other parameters are the same as for Figure 2.
See this image and copyright information in PMC

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