Efficient charge generation by relaxed charge-transfer states at organic interfaces

Koen Vandewal; Steve Albrecht; Eric T. Hoke; Kenneth R. Graham; Johannes Widmer; Jessica D. Douglas; Marcel Schubert; William R. Mateker; Jason T. Bloking; George F. Burkhard; Alan Sellinger; Jean M.J. Fréchet; Aram Amassian; Moritz K. Riede; Michael D. McGehee; Dieter Neher; Alberto Salleo

doi:10.1038/nmat3807

Efficient charge generation by relaxed charge-transfer states at organic interfaces

Koen Vandewal, Steve Albrecht, Eric T. Hoke, Kenneth R. Graham, Johannes Widmer, Jessica D. Douglas, Marcel Schubert, William R. Mateker, Jason T. Bloking, George F. Burkhard, Alan Sellinger, Jean M.J. Fréchet, Aram Amassian, Moritz K. Riede, Michael D. McGehee, Dieter Neher, Alberto Salleo

Research output: Contribution to journal › Article › peer-review

671 Scopus citations

Abstract

Interfaces between organic electron-donating (D) and electron-accepting (A) materials have the ability to generate charge carriers on illumination. Efficient organic solar cells require a high yield for this process, combined with a minimum of energy losses. Here, we investigate the role of the lowest energy emissive interfacial charge-transfer state (CT₁) in the charge generation process. We measure the quantum yield and the electric field dependence of charge generation on excitation of the charge-transfer (CT) state manifold via weakly allowed, low-energy optical transitions. For a wide range of photovoltaic devices based on polymer:fullerene, small-molecule:C₆₀ and polymer:polymer blends, our study reveals that the internal quantum efficiency (IQE) is essentially independent of whether or not D, A or CT states with an energy higher than that of CT₁ are excited. The best materials systems show an IQE higher than 90% without the need for excess electronic or vibrational energy.

Original language	English
Pages (from-to)	63-68
Number of pages	6
Journal	Nature Materials
Volume	13
Issue number	1
DOIs	https://doi.org/10.1038/nmat3807
State	Published - Jan 2014

Bibliographical note

Funding Information:
This publication was supported by the Center for Advanced Molecular Photovoltaics (Award No KUS-C1-015-21) and the Department of Energy, Laboratory Directed Research and Development funding, under contract DE-AC02-76SF00515. The PCDTBT used in this work was provided by St-Jean Photochemicals. M.K.R. acknowledges financial support by the BMBF through project 03IP602 and J.W. acknowledges support from the Heinrich-Böll-Stiftung. S.A. and M.S. acknowledge financial support by the BMBF within PVcomB (FKZ 03IS2151D) and the DFG (SPP 1355). D.N. thanks the DFG for financially supporting a travel grant. K.R.G. and A.A. acknowledge SABIC for a post-doctoral fellowship. The authors thank J. Kurpiers for technical assistance with the TDCF set-up.

ASJC Scopus subject areas

General Chemistry
General Materials Science
Condensed Matter Physics
Mechanics of Materials
Mechanical Engineering

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This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1038/nmat3807

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Vandewal, K., Albrecht, S., Hoke, E. T., Graham, K. R., Widmer, J., Douglas, J. D., Schubert, M., Mateker, W. R., Bloking, J. T., Burkhard, G. F., Sellinger, A., Fréchet, J. M. J., Amassian, A., Riede, M. K., McGehee, M. D., Neher, D., & Salleo, A. (2014). Efficient charge generation by relaxed charge-transfer states at organic interfaces. Nature Materials, 13(1), 63-68. https://doi.org/10.1038/nmat3807

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title = "Efficient charge generation by relaxed charge-transfer states at organic interfaces",

abstract = "Interfaces between organic electron-donating (D) and electron-accepting (A) materials have the ability to generate charge carriers on illumination. Efficient organic solar cells require a high yield for this process, combined with a minimum of energy losses. Here, we investigate the role of the lowest energy emissive interfacial charge-transfer state (CT1) in the charge generation process. We measure the quantum yield and the electric field dependence of charge generation on excitation of the charge-transfer (CT) state manifold via weakly allowed, low-energy optical transitions. For a wide range of photovoltaic devices based on polymer:fullerene, small-molecule:C60 and polymer:polymer blends, our study reveals that the internal quantum efficiency (IQE) is essentially independent of whether or not D, A or CT states with an energy higher than that of CT1 are excited. The best materials systems show an IQE higher than 90% without the need for excess electronic or vibrational energy.",

author = "Koen Vandewal and Steve Albrecht and Hoke, {Eric T.} and Graham, {Kenneth R.} and Johannes Widmer and Douglas, {Jessica D.} and Marcel Schubert and Mateker, {William R.} and Bloking, {Jason T.} and Burkhard, {George F.} and Alan Sellinger and Fr{\'e}chet, {Jean M.J.} and Aram Amassian and Riede, {Moritz K.} and McGehee, {Michael D.} and Dieter Neher and Alberto Salleo",

note = "Funding Information: This publication was supported by the Center for Advanced Molecular Photovoltaics (Award No KUS-C1-015-21) and the Department of Energy, Laboratory Directed Research and Development funding, under contract DE-AC02-76SF00515. The PCDTBT used in this work was provided by St-Jean Photochemicals. M.K.R. acknowledges financial support by the BMBF through project 03IP602 and J.W. acknowledges support from the Heinrich-B{\"o}ll-Stiftung. S.A. and M.S. acknowledge financial support by the BMBF within PVcomB (FKZ 03IS2151D) and the DFG (SPP 1355). D.N. thanks the DFG for financially supporting a travel grant. K.R.G. and A.A. acknowledge SABIC for a post-doctoral fellowship. The authors thank J. Kurpiers for technical assistance with the TDCF set-up.",

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Vandewal, K, Albrecht, S, Hoke, ET, Graham, KR, Widmer, J, Douglas, JD, Schubert, M, Mateker, WR, Bloking, JT, Burkhard, GF, Sellinger, A, Fréchet, JMJ, Amassian, A, Riede, MK, McGehee, MD, Neher, D & Salleo, A 2014, 'Efficient charge generation by relaxed charge-transfer states at organic interfaces', Nature Materials, vol. 13, no. 1, pp. 63-68. https://doi.org/10.1038/nmat3807

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T1 - Efficient charge generation by relaxed charge-transfer states at organic interfaces

AU - Vandewal, Koen

AU - Albrecht, Steve

AU - Hoke, Eric T.

AU - Graham, Kenneth R.

AU - Widmer, Johannes

AU - Douglas, Jessica D.

AU - Schubert, Marcel

AU - Mateker, William R.

AU - Bloking, Jason T.

AU - Burkhard, George F.

AU - Sellinger, Alan

AU - Fréchet, Jean M.J.

AU - Amassian, Aram

AU - Riede, Moritz K.

AU - McGehee, Michael D.

AU - Neher, Dieter

AU - Salleo, Alberto

N1 - Funding Information: This publication was supported by the Center for Advanced Molecular Photovoltaics (Award No KUS-C1-015-21) and the Department of Energy, Laboratory Directed Research and Development funding, under contract DE-AC02-76SF00515. The PCDTBT used in this work was provided by St-Jean Photochemicals. M.K.R. acknowledges financial support by the BMBF through project 03IP602 and J.W. acknowledges support from the Heinrich-Böll-Stiftung. S.A. and M.S. acknowledge financial support by the BMBF within PVcomB (FKZ 03IS2151D) and the DFG (SPP 1355). D.N. thanks the DFG for financially supporting a travel grant. K.R.G. and A.A. acknowledge SABIC for a post-doctoral fellowship. The authors thank J. Kurpiers for technical assistance with the TDCF set-up.

PY - 2014/1

Y1 - 2014/1

N2 - Interfaces between organic electron-donating (D) and electron-accepting (A) materials have the ability to generate charge carriers on illumination. Efficient organic solar cells require a high yield for this process, combined with a minimum of energy losses. Here, we investigate the role of the lowest energy emissive interfacial charge-transfer state (CT1) in the charge generation process. We measure the quantum yield and the electric field dependence of charge generation on excitation of the charge-transfer (CT) state manifold via weakly allowed, low-energy optical transitions. For a wide range of photovoltaic devices based on polymer:fullerene, small-molecule:C60 and polymer:polymer blends, our study reveals that the internal quantum efficiency (IQE) is essentially independent of whether or not D, A or CT states with an energy higher than that of CT1 are excited. The best materials systems show an IQE higher than 90% without the need for excess electronic or vibrational energy.

AB - Interfaces between organic electron-donating (D) and electron-accepting (A) materials have the ability to generate charge carriers on illumination. Efficient organic solar cells require a high yield for this process, combined with a minimum of energy losses. Here, we investigate the role of the lowest energy emissive interfacial charge-transfer state (CT1) in the charge generation process. We measure the quantum yield and the electric field dependence of charge generation on excitation of the charge-transfer (CT) state manifold via weakly allowed, low-energy optical transitions. For a wide range of photovoltaic devices based on polymer:fullerene, small-molecule:C60 and polymer:polymer blends, our study reveals that the internal quantum efficiency (IQE) is essentially independent of whether or not D, A or CT states with an energy higher than that of CT1 are excited. The best materials systems show an IQE higher than 90% without the need for excess electronic or vibrational energy.

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JO - Nature Materials

JF - Nature Materials

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Efficient charge generation by relaxed charge-transfer states at organic interfaces

Abstract

Bibliographical note

ASJC Scopus subject areas

UN SDGs

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