Title
Simulation of surface-directed phase separation in a solution-processed polymer/PCBM blend
Author
Michels, J.J.
Moons, E.
Publication year
2013
Abstract
The formation of the surface-induced stratified lamellar composition profile experimentally evidenced in spincoated layers of the photovoltaic donor-acceptor blend consisting of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-5,5- (4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole]/ phenyl-C61-butyric acid methyl ester (APFO-3/PCBM), as processed from chloroform, is simulated using square gradient theory extended with terms describing the interaction of the blend components with the air and substrate interfaces. The surface energy contributions have been formulated based on an enthalpic nearest-neighbor model which allows integration of common surface tension theory and experimentally accessible surface energies of the fluid phase constituents with a mean field description of a multicomponent blend confined by substrate and air interfaces. Using estimates for the quench depth and transport properties of the blend components as a function of polymer concentration, the time-resolved numerical simulations yield results that compare favorably with experimental observations, both in terms of the number of lamellae as a function of the blend layer thickness and their compositional order. The effect of blend ratio is reproduced as well, the lamellar pattern becoming more pronounced if the amount of PCBM increases relative to APFO-3. © 2013 American Chemical Society.
Subject
Mechatronics, Mechanics & Materials
HOL - Holst
TS - Technical Sciences
High Tech Systems & Materials
Materials
Industrial Innovation
Composition profile
Donor-acceptor blends
Mean-field description
Multicomponent blends
Polymer concentrations
Solution-processed polymer
Square gradient theory
Surface energy contribution
Interfacial energy
Phase separation
Transport properties
Interfaces (materials)
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http://resolver.tudelft.nl/uuid:ed7e126b-41fe-4bbd-b598-3063d152b10e
DOI
https://doi.org/10.1021/ma400269j
TNO identifier
484287
ISSN
0024-9297
Source
Macromolecules, 46 (21), 8693-8701
Document type
article