Role of coherence and delocalization in photo-induced electron transfer at organic interfaces

V. Abramavicius; V. Pranculis; A. Melianas; O. Inganäs; V. Gulbinas; D. Abramavicius

doi:10.1038/srep32914

journal article Open Access Sep 08, 2016

Role of coherence and delocalization in photo-induced electron transfer at organic interfaces

V. Abramavicius V. Pranculis A. Melianas O. Inganäs V. Gulbinas D. Abramavicius

Scientific Reports Vol. 6 No. 1 · Springer Science and Business Media LLC

View at Publisher Save 10.1038/srep32914

Abstract

AbstractPhoto-induced charge transfer at molecular heterojunctions has gained particular interest due to the development of organic solar cells (OSC) based on blends of electron donating and accepting materials. While charge transfer between donor and acceptor molecules can be described by Marcus theory, additional carrier delocalization and coherent propagation might play the dominant role. Here, we describe ultrafast charge separation at the interface of a conjugated polymer and an aggregate of the fullerene derivative PCBM using the stochastic Schrödinger equation (SSE) and reveal the complex time evolution of electron transfer, mediated by electronic coherence and delocalization. By fitting the model to ultrafast charge separation experiments, we estimate the extent of electron delocalization and establish the transition from coherent electron propagation to incoherent hopping. Our results indicate that even a relatively weak coupling between PCBM molecules is sufficient to facilitate electron delocalization and efficient charge separation at organic interfaces.

Topics

No keywords indexed for this article. Browse by subject →

References

18

[1]

Deibel, C., Storbel, T. & Dyakonov, V. Origin of the efficient polaron-pair dissociation in polymer-fullerene blends. Phys. Rev. Lett. 103, 036402 (2009). 10.1103/physrevlett.103.036402

[2]

Bakulin, A. A. et al. The role of driving energy and delocalized states for charge separation in organic semiconductors. Science 335, 1340–1344 (2012). 10.1126/science.1217745

[3]

Grancini, G. et al. Hot exciton dissociation in polymer solar cells. Nat. Mater. 12, 29−33 (2013). 10.1038/nmat3502

[4]

Jailaubekov, A. E. et al. Hot charge-transfer excitons set the time limit for charge separation at donor/acceptor interfaces in organic photovoltaics. Nat. Mater. 12, 66–73 (2013). 10.1038/nmat3500

[5]

Gélinas, S. et al. Ultrafast long-range charge separation in organic semiconductor photovoltaic diodes. Science, 343, 512–516 (2014). 10.1126/science.1246249

[6]

Lee, M. H., Aragó, J. & Troisi, A. Charge Dynamics in Organic Photovoltaic Materials: Interplay between Quantum Diffusion and Quantum Relaxation. J. Phys. Chem. C 119, 14899–14998 (2015).

[7]

Vithanage, D. A. et al. Visualizing charge separation in bulk heterojunction organic solar cells. Nat. Commun. 4, 2334 (2013). 10.1038/ncomms3334

[8]

Abramavicius, V. & Abramavicius, D., Excitation transfer pathways in excitonic aggregates revealed by the stochastic Schrödinger equation. J. Chem. Phys. 140, 065103 (2014). 10.1063/1.4863968

[9]

Valkunas, L., Abramavicius, D. & Mančal, T. Molecular Excitation Dynamics and Relaxation: Quantum Theory and Spectroscopy (John Wiley & Sons, 2013). 10.1002/9783527653652

[10]

Devizis, A., Serbenta, A., Meerholz, K., Hertel, D. & Gulbinas, V. Ultrafast dynamics of carrier mobility in a conjugated polymer probed at molecular and microscopic length scales. Phys. Rev. Lett. 103, 027404 (2009). 10.1103/physrevlett.103.027404

[11]

Pranculis, V. et al. Charge carrier generation and transport in different stoichiometry APFO3:PC61BM solar cells. J. Am. Chem. Soc. 136, 11331–11338 (2014). 10.1021/ja503301m

[12]

Melianas, A. et al. Dispersion-dominated photocurrent in polymer:fullerene solar cells. Adv. Funct. Mater. 24, 4507–4514 (2014). 10.1002/adfm.201400404

[13]

Vandewal, K. et al. Efficient charge generation by relaxed charge-transfer states at organic interfaces. Nat. Mater. 13, 63–68 (2014). 10.1038/nmat3807

[14]

Vandewal, K. et al. Quantification of Quantum Efficiency and Energy Losses in Low Bandgap Polymer:Fullerene Solar Cells with High Open-Circuit Voltage. Adv. Funct. Mater. 22, 3480–3490 (2012). 10.1002/adfm.201200608

[15]

Devižis, A., Hertel, D., Meerholz, K., Gulbinas, V. & Moser, J. A. Time-independent, high electron mobility in thin PC61BM films: Relevance to organic photovoltaics. Org. Electron. 15, 3729–3734 (2014). 10.1016/j.orgel.2014.10.028

[16]

Barker, A. J., Chen, K. & Hodgkiss, J. M. Distance Distributions of Photogenerated Charge Pairs in Organic Photovoltaic Cells. J. Am. Chem. Soc. 136, 12018–12026 (2014). 10.1021/ja505380j

[17]

van Eersel, H., Janssen, R. A. J. & Kemerink, M. Mechanism for Efficient Photoinduced Charge Separation at Disordered Organic Heterointerfaces. Adv. Funct. Mater. 22, 2700–2708 (2012). 10.1002/adfm.201200249

[18]

Murthy, D. H. K. et al. Origin of reduced bimolecular recombination in blends of conjugated polymers and fullerenes. Adv. Funct. Mater. 23, 4262–4268 (2014). 10.1002/adfm.201203852

Metrics

43

Citations

18

References

Details

Published: Sep 08, 2016
Vol/Issue: 6(1)
License: View

Authors

University of Linköping, IFM, S-58183 Linköping, Sweden

Cite This Article

V. Abramavicius, V. Pranculis, A. Melianas, et al. (2016). Role of coherence and delocalization in photo-induced electron transfer at organic interfaces. Scientific Reports, 6(1). https://doi.org/10.1038/srep32914

Role of coherence and delocalization in photo-induced electron transfer at organic interfaces

You May Also Like