Phase behaviour of liquid-crystalline polymer/fullerene organic photovoltaic blends: thermal stability and miscibility

Müller, Christian; Bergqvist, Jonas; Vandewal, Koen; Tvingstedt, Kristofer; Anselmo, Ana Sofia; Magnusson, Roger; Alonso, M. I.; Moons, Ellen; Arwin, Hans; Campoy‐Quiles, Mariano; Inganäs, Olle

doi:10.1039/c1jm11239b

Cited by 81 publications

(107 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Consistent with previous observations, we observe a redshift of E CT with increasing C 60 fraction [10][11][12][13][14] , but find that modelling based on the accompanying change in dielectric constant via the solid-state solvation effect (SSSE) 15 can only explain the data at high (450%) C 60 loading. We find that E CT at low fullerene concentration is higher than expected from the change in dielectric constant and attribute this discrepancy to increased localization of the electron component of the CT state because of a reduction in average C 60 crystallite size below B4 nm.…”

supporting

confidence: 79%

Delocalization and dielectric screening of charge transfer states in organic photovoltaic cells

et al. 2014

View full text Add to dashboard Cite

Charge transfer (CT) states at a donor-acceptor heterojunction have a key role in the charge photogeneration process of organic solar cells, however, the mechanism by which these states dissociate efficiently into free carriers remains unclear. Here we explore the nature of these states in small molecule-fullerene bulk heterojunction photovoltaics with varying fullerene fraction and find that the CT energy scales with dielectric constant at high fullerene loading but that there is a threshold C 60 crystallite size of B4 nm below which the spatial extent of these states is reduced. Electroabsorption measurements indicate an increase in CT polarizability when C 60 crystallite size exceeds this threshold, and that this change is correlated with increased charge separation yield supported by CT photoluminescence transients. These results support a model of charge separation via delocalized CT states independent of excess heterojunction offset driving energy and indicate that local fullerene crystallinity is critical to the charge separation process.

show abstract

supporting

confidence: 79%

Delocalization and dielectric screening of charge transfer states in organic photovoltaic cells

et al. 2014

View full text Add to dashboard Cite

show abstract

“…It has been shown that miscibility is a parameter controlling the fill factor of OPV devices 34 but also their microstructural stability. 13,35 Such polymer arrangement with monomers co-facial to the small molecule acceptor are also likely to be beneficial for charge transfer and thus, charge generation. Thus, we speculate that the knowledge of such specific interactions can lead to the design and selection of small molecule acceptors to improve morphological robustness.…”

Section: -18mentioning

confidence: 99%

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

et al. 2017

View full text Add to dashboard Cite

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.

show abstract

“…poly(3-hexylthiophene):phenyl-C 61 -butyric acid methyl ester (P3HT:PCBM), three phases have been recognized 28 and confirmed by other studies. 15,[28][29][30][31][32][33][34][35][36] These consist of a pure, mostly crystalline P3HT phase (also referred to as "aggregated"), a mixed amorphous P3HT:fullerene phase, and a fullerene-rich phase.…”

Section: Introductionmentioning

confidence: 99%

Quantifying organic solar cell morphology: a computational study of three-dimensional maps

Wodo

Roehling

Moulé

et al. 2013

Energy Environ. Sci.

View full text Add to dashboard Cite

Establishing how fabrication conditions quantitatively affect the morphology of organic blends opens the possibility of rationally designing higher efficiency materials, yet such a relationship remains elusive. One of the major challenges stems from incomplete three-dimensional representations of morphology, which is due to the difficulties of performing accurate morphological measurements. Recently, three-dimensional measurements of mixed organic layers using electron tomography with high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) provided maps of morphology with high resolution and detail. Using a simple, yet powerful, computational tool kit, these complex 3D datasets are converted into a set of physically meaningful morphology descriptors. These descriptors provide means for converting these large, complicated data sets (∼5×10 7 voxels) into simple, descriptive parameters, enabling a quantitative comparison between morphologies fabricated under different conditions. A set of P3HT:endohedral fullerene bulk-heterojunctions, fabricated under conditions specifically chosen to yield a wide range of morphologies, are examined. The effects of processing conditions and electrode presence on interfacial area, domain size distribution, connectivity, and tortuosity of charge transport paths are herein determined directly from real-space data for the first time. Through this characterization, quantitative insights into the role of processing on morphology are provided, as well as a more complete picture of the consequences of a three-phase morphology. The analysis demonstrates a methodology which can enable a deeper understanding into morphology control.

show abstract

Phase behaviour of liquid-crystalline polymer/fullerene organic photovoltaic blends: thermal stability and miscibility

Cited by 81 publications

References 60 publications

Delocalization and dielectric screening of charge transfer states in organic photovoltaic cells

Delocalization and dielectric screening of charge transfer states in organic photovoltaic cells

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

Quantifying organic solar cell morphology: a computational study of three-dimensional maps

Contact Info

Product

Resources

About