Polymer Solar Cells : solubility controls fiber network formation

J.J. Franeker, van, G.H.L. Heintges, C. Schaefer, Weiwei Li, M.M. Wienk, P.P.A.M. Schoot, van der, R.A.J. Janssen

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Abstract

The photoactive layer of polymer solar cells is commonly processed from a four-component solution, containing a semiconducting polymer and a fullerene derivative dissolved in a solvent–cosolvent mixture. The nanoscale dimensions of the polymer–fullerene morphology that is formed upon drying determines the solar cell performance, but the fundamental processes that govern the size of the phase-separated polymer and fullerene domains are poorly understood. Here, we investigate morphology formation of an alternating copolymer of diketopyrrolopyrrole and a thiophene-phenyl-thiophene oligomer (PDPPTPT) with relatively long 2-decyltetradecyl (DT) side chains blended with [6,6]-phenyl-C71-butyric acid methyl ester. During solvent evaporation the polymer crystallizes into a fibrous network. The typical width of these fibers is analyzed by quantification of transmission electron microscopic images, and is mainly determined by the solubility of the polymer in the cosolvent and the molecular weight of the polymer. A higher molecular weight corresponds to a lower solubility and film processing results in a smaller fiber width. Surprisingly, the fiber width is not related to the drying rate or the amount of cosolvent. We have made solar cells with fiber widths ranging from 28 to 68 nm and found an inverse relation between fiber width and photocurrent. Finally, by mixing two cosolvents, we develop a ternary solvent system to tune the fiber width. We propose a model based on nucleation-and-growth which can explain these measurements. Our results show that the width of the semicrystalline polymer fibers is not the result of a frozen dynamical state, but determined by the nucleation induced by the polymer solubility.
Original languageEnglish
Pages (from-to)11783-11794
Number of pages12
JournalJournal of the American Chemical Society
Volume137
Issue number36
DOIs
Publication statusPublished - 2015

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Solubility
Polymers
Fibers
Fullerenes
Thiophenes
Thiophene
Solar cells
Drying
Nucleation
Molecular weight
Semiconducting polymers
Molecular Weight
Butyric acid
Butyric Acid
Polymer solar cells
Photocurrents
Oligomers
Esters
Evaporation
Copolymers

Cite this

Franeker, van, J.J. ; Heintges, G.H.L. ; Schaefer, C. ; Li, Weiwei ; Wienk, M.M. ; Schoot, van der, P.P.A.M. ; Janssen, R.A.J. / Polymer Solar Cells : solubility controls fiber network formation. In: Journal of the American Chemical Society. 2015 ; Vol. 137, No. 36. pp. 11783-11794.
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abstract = "The photoactive layer of polymer solar cells is commonly processed from a four-component solution, containing a semiconducting polymer and a fullerene derivative dissolved in a solvent–cosolvent mixture. The nanoscale dimensions of the polymer–fullerene morphology that is formed upon drying determines the solar cell performance, but the fundamental processes that govern the size of the phase-separated polymer and fullerene domains are poorly understood. Here, we investigate morphology formation of an alternating copolymer of diketopyrrolopyrrole and a thiophene-phenyl-thiophene oligomer (PDPPTPT) with relatively long 2-decyltetradecyl (DT) side chains blended with [6,6]-phenyl-C71-butyric acid methyl ester. During solvent evaporation the polymer crystallizes into a fibrous network. The typical width of these fibers is analyzed by quantification of transmission electron microscopic images, and is mainly determined by the solubility of the polymer in the cosolvent and the molecular weight of the polymer. A higher molecular weight corresponds to a lower solubility and film processing results in a smaller fiber width. Surprisingly, the fiber width is not related to the drying rate or the amount of cosolvent. We have made solar cells with fiber widths ranging from 28 to 68 nm and found an inverse relation between fiber width and photocurrent. Finally, by mixing two cosolvents, we develop a ternary solvent system to tune the fiber width. We propose a model based on nucleation-and-growth which can explain these measurements. Our results show that the width of the semicrystalline polymer fibers is not the result of a frozen dynamical state, but determined by the nucleation induced by the polymer solubility.",
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Polymer Solar Cells : solubility controls fiber network formation. / Franeker, van, J.J.; Heintges, G.H.L.; Schaefer, C.; Li, Weiwei; Wienk, M.M.; Schoot, van der, P.P.A.M.; Janssen, R.A.J.

In: Journal of the American Chemical Society, Vol. 137, No. 36, 2015, p. 11783-11794.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Polymer Solar Cells : solubility controls fiber network formation

AU - Franeker, van, J.J.

AU - Heintges, G.H.L.

AU - Schaefer, C.

AU - Li, Weiwei

AU - Wienk, M.M.

AU - Schoot, van der, P.P.A.M.

AU - Janssen, R.A.J.

PY - 2015

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N2 - The photoactive layer of polymer solar cells is commonly processed from a four-component solution, containing a semiconducting polymer and a fullerene derivative dissolved in a solvent–cosolvent mixture. The nanoscale dimensions of the polymer–fullerene morphology that is formed upon drying determines the solar cell performance, but the fundamental processes that govern the size of the phase-separated polymer and fullerene domains are poorly understood. Here, we investigate morphology formation of an alternating copolymer of diketopyrrolopyrrole and a thiophene-phenyl-thiophene oligomer (PDPPTPT) with relatively long 2-decyltetradecyl (DT) side chains blended with [6,6]-phenyl-C71-butyric acid methyl ester. During solvent evaporation the polymer crystallizes into a fibrous network. The typical width of these fibers is analyzed by quantification of transmission electron microscopic images, and is mainly determined by the solubility of the polymer in the cosolvent and the molecular weight of the polymer. A higher molecular weight corresponds to a lower solubility and film processing results in a smaller fiber width. Surprisingly, the fiber width is not related to the drying rate or the amount of cosolvent. We have made solar cells with fiber widths ranging from 28 to 68 nm and found an inverse relation between fiber width and photocurrent. Finally, by mixing two cosolvents, we develop a ternary solvent system to tune the fiber width. We propose a model based on nucleation-and-growth which can explain these measurements. Our results show that the width of the semicrystalline polymer fibers is not the result of a frozen dynamical state, but determined by the nucleation induced by the polymer solubility.

AB - The photoactive layer of polymer solar cells is commonly processed from a four-component solution, containing a semiconducting polymer and a fullerene derivative dissolved in a solvent–cosolvent mixture. The nanoscale dimensions of the polymer–fullerene morphology that is formed upon drying determines the solar cell performance, but the fundamental processes that govern the size of the phase-separated polymer and fullerene domains are poorly understood. Here, we investigate morphology formation of an alternating copolymer of diketopyrrolopyrrole and a thiophene-phenyl-thiophene oligomer (PDPPTPT) with relatively long 2-decyltetradecyl (DT) side chains blended with [6,6]-phenyl-C71-butyric acid methyl ester. During solvent evaporation the polymer crystallizes into a fibrous network. The typical width of these fibers is analyzed by quantification of transmission electron microscopic images, and is mainly determined by the solubility of the polymer in the cosolvent and the molecular weight of the polymer. A higher molecular weight corresponds to a lower solubility and film processing results in a smaller fiber width. Surprisingly, the fiber width is not related to the drying rate or the amount of cosolvent. We have made solar cells with fiber widths ranging from 28 to 68 nm and found an inverse relation between fiber width and photocurrent. Finally, by mixing two cosolvents, we develop a ternary solvent system to tune the fiber width. We propose a model based on nucleation-and-growth which can explain these measurements. Our results show that the width of the semicrystalline polymer fibers is not the result of a frozen dynamical state, but determined by the nucleation induced by the polymer solubility.

U2 - 10.1021/jacs.5b07228

DO - 10.1021/jacs.5b07228

M3 - Article

C2 - 26306585

VL - 137

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EP - 11794

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 36

ER -