Petascale Simulations of the Morphology and the Molecular Interface of Bulk Heterojunctions

Carrillo, Jan‐Michael Y.; Seibers, Zach D.; Kumar, Rajeev; Matheson, Michael A.; Ankner, John F.; Goswami, Monojoy; Bhaskaran‐Nair, Kiran; Shelton, W. A.; Sumpter, Bobby G.; Kilbey, S. Michael

doi:10.1021/acsnano.6b03009

Cited by 24 publications

(35 citation statements)

References 79 publications

(159 reference statements)

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“…This self-organizing propensity seems to be induced by the geometrical features of P3HT chains. It should be stressed that no explicitly ad-hoc anisotropic interaction has been introduced between thiophene rings, in contrast to the strategy proposed by Carrillo et al 26 in order to improve the “ultra” CG model of Lee et al. 22 (also referred to as the LPC model 26 ).…”

Section: Resultsmentioning

confidence: 99%

“…In particular, coarse-grain (CG) molecular dynamics (MD) simulations are often employed to model BHJs, 22−26 being able to capture the morphology at relevant length scales while still retaining a molecular description (as opposed to Monte Carlo simulated annealing 27−29 or mean field 30 approaches where that is lost). However, CG models developed to date are not readily transferable.…”

Section: Introductionmentioning

confidence: 99%

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Bulk Heterojunction Morphologies with Atomistic Resolution from Coarse-Grain Solvent Evaporation Simulations

Alessandri¹,

Uusitalo²,

Vries³

et al. 2017

J. Am. Chem. Soc.

157

270

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Control over the morphology of the active layer of bulk heterojunction (BHJ) organic solar cells is paramount to achieve high-efficiency devices. However, no method currently available can predict morphologies for a novel donor–acceptor blend. An approach which allows reaching relevant length scales, retaining chemical specificity, and mimicking experimental fabrication conditions, and which is suited for high-throughput schemes has been proven challenging to find. Here, we propose a method to generate atom-resolved morphologies of BHJs which conforms to these requirements. Coarse-grain (CG) molecular dynamics simulations are employed to simulate the large-scale morphological organization during solution-processing. The use of CG models which retain chemical specificity translates into a direct path to the rational design of donor and acceptor compounds which differ only slightly in chemical nature. Finally, the direct retrieval of fully atomistic detail is possible through backmapping, opening the way for improved quantum mechanical calculations addressing the charge separation mechanism. The method is illustrated for the poly(3-hexyl-thiophene) (P3HT)–phenyl-C61-butyric acid methyl ester (PCBM) mixture, and found to predict morphologies in agreement with experimental data. The effect of drying rate, P3HT molecular weight, and thermal annealing are investigated extensively, resulting in trends mimicking experimental findings. The proposed methodology can help reduce the parameter space which has to be explored before obtaining optimal morphologies not only for BHJ solar cells but also for any other solution-processed soft matter device.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Bulk Heterojunction Morphologies with Atomistic Resolution from Coarse-Grain Solvent Evaporation Simulations

Alessandri¹,

Uusitalo²,

Vries³

et al. 2017

J. Am. Chem. Soc.

157

270

View full text Add to dashboard Cite

show abstract

“…Carrillo et al 15 and Liu et al 16 assume that blends have a phase-separated microstructure with pure crystalline components and pure amorphous components. In all cases, they find that co-faciality between P3HT and PCBM is favoured.…”

Section: Toc Graphicsmentioning

confidence: 99%

“…29 Also, supramolecular crown ether and metal complex with corannulene derivative ligands have also been shown to embraced C60 fullerene. [30][31] Previous MD studies on P3HT:PCBM [15][16]20 have focused on modelling adjacent slabs of pure P3HT and pure PCBM while experimental studies evidence the presence of an amorphous mixture of P3HT and PCBM. 2 The wrapping effect has not been observed due to the constrained molecular arrangement in adjacent slab.…”

Section: -3ht-pcbm -50 -45mentioning

confidence: 99%

Quantitative Analysis of the Molecular Dynamics of P3HT:PCBM Bulk Heterojunction

et al. 2017

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The optoelectronic properties of blends of conjugated polymers and small molecules are likely to be affected by the molecular dynamics of the active layer components. We study the dynamics of regioregular poly(3-hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM) blends using molecular dynamics (MD) simulation on time scales up to 50 ns and in a temperature range of 250−360 K. First, we compare the MD results with quasi-elastic neutron-scattering (QENS) measurements. Experiment and simulation give evidence of the vitrification of P3HT upon blending and the plasticization of PCBM by P3HT. Second, we reconstruct the QENS signal based on the independent simulations of the three phases constituting the complex microstructure of such blends. Finally, we found that P3HT chains tend to wrap around PCBM molecules in the amorphous mixture of P3HT and PCBM; this molecular interaction between P3HT and PCBM is likely to be responsible for the observed frustration of P3HT, the plasticization of PCBM, and the partial miscibility of P3HT and PCBM.

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“…Choice of constituent donor and acceptor materials are important as the excitons (unstable bound electron–hole pairs) separate into electrons and holes due to the built‐in electric field at the interfaces of donor and acceptor domains . Several previous computational as well as experimental efforts have examined OSCs composed of the conjugated electron–donor polymer, poly‐(3‐hexyl‐thiophene) (P3HT), and the fullerene‐based acceptor molecule, phenyl‐C61‐butyric acid methyl ester (PCBM) . The materials selection has been driven by the ease of availability, inexpensive synthesis, and thermomechanical stability .…”

Section: Introductionmentioning

confidence: 99%

Effect of polydispersity on the bulk‐heterojunction morphology of P3HT:PCBM solar cells

Munshi

Ghumman

Iyer

et al. 2019

J Polym Sci B Polym Phys

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Bulk heterojunctions (BHJs) based on semiconducting electron–donor polymer and electron–acceptor fullerene have been extensively investigated as potential photoactive layers for organic solar cells (OSCs). In the experimental studies, poly‐(3‐hexyl‐thiophene) (P3HT) polymers are hardly monodisperse as the synthesis of highly monodisperse polymer mixture is a near impossible task to achieve. However, the majority of the computational efforts on P3HT: phenyl‐C61‐butyric acid methyl ester (P3HT:PCBM)‐based OSCs, a monodisperse P3HT is usually considered. Here, results from coarse‐grained molecular dynamics simulations of solvent evaporation and thermal annealing process of the BHJ are shared describing the effect of variability in molecular weight (also known as polydispersity) on the morphology of the active layer. Results affirm that polydispersity is beneficial for charge separation as the interfacial area is observed to increase with higher dispersity. Calculations of percolation and orientation tensors, on the other hand, reveal that a certain polydispersity index ranging between 1.05 and 1.10 should be maintained for optimal charge transport. Most importantly, these results point out that the consideration of polydispersity should be considered in computational studies of polymer‐based OSCs. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 895–903

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Petascale Simulations of the Morphology and the Molecular Interface of Bulk Heterojunctions

Cited by 24 publications

References 79 publications

Bulk Heterojunction Morphologies with Atomistic Resolution from Coarse-Grain Solvent Evaporation Simulations

Bulk Heterojunction Morphologies with Atomistic Resolution from Coarse-Grain Solvent Evaporation Simulations

Quantitative Analysis of the Molecular Dynamics of P3HT:PCBM Bulk Heterojunction

Effect of polydispersity on the bulk‐heterojunction morphology of P3HT:PCBM solar cells

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