Evaluation of the Process of Solvent Vapor Annealing on Organic Thin Films

Handle URI:
http://hdl.handle.net/10754/209397
Title:
Evaluation of the Process of Solvent Vapor Annealing on Organic Thin Films
Authors:
Ren, Yi
Abstract:
Solvent vapor annealing has recently emerged as an intriguing, room-temperature, and highly versatile alternative to thermal annealing. The chemically selective interaction between solvents and organic semiconductors opens new opportunities to selectively anneal certain components of the device, while leaving others intact. On the downside, these interactions are complex and rather unpredictable, requiring further investigation. We propose a novel methodology to investigate solvent-film interactions, based on use of an in situ quartz crystal microbalance with dissipation (QCM-D) capability and in situ grazing incidence wide angle X-ray scattering (GIWAXS). These methods make it possible to investigate both qualitatively and quantitatively the solvent vapor uptake, the resulting softening and changes (reversible and/or irreversible) in crystallinity. Using this strategy, we have investigated the solvent vapor annealing of traditional donor and acceptor materials, namely poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-Phenyl-C61-butyric acid methyl ester (PCBM). We find these materials retain their rigid structure during toluene vapor annealing and do not dewet. We also investigated the toluene vapor annealing of several newly proposed acceptor molecules (pentacene-based) modified with various silyl groups and electron withdrawing groups to tune the packing structure of the acceptor domains and energy levels at the donor-acceptor interface. We found a dramatic effect of the electron-withdrawing group on vapor uptake and whether the film remains rigid, softens, or dissolves completely. In the case of trifluoromethyl electron-withdrawing group, we found the film dissolves, resulting in complete and irreversible loss of long range order. By contrast, the cyano group prevented loss of long range order, instead promoting crystallization in some cases. The silyl groups had a secondary effect in comparison to these. In the last part of the thesis, we investigated the toluene vapor annealing of P3HT-based blends. In general, the blend behavior was strongly affected by the choice of the acceptor. Nevertheless, the polymer mediated the outcome, maintaining the integrity of the blend and preventing dewetting altogether. The TIPS (silyl) substituted pentacene molecules consistently segregated from the blend and crystallized on the surface, revealing their incompatibility with P3HT.
Advisors:
Amassian, Aram ( 0000-0002-5734-1194 )
Committee Member:
Bakr, Osman ( 0000-0002-3428-1002 ) ; Wang, Peng ( 0000-0003-0856-0865 )
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Program:
Chemical and Biological Engineering
Issue Date:
Jul-2011
Type:
Thesis
Appears in Collections:
Theses; Physical Sciences and Engineering (PSE) Division; Chemical and Biological Engineering Program

Full metadata record

DC FieldValue Language
dc.contributor.advisorAmassian, Aramen
dc.contributor.authorRen, Yien
dc.date.accessioned2012-02-04T08:30:48Z-
dc.date.available2012-02-04T08:30:48Z-
dc.date.issued2011-07en
dc.identifier.urihttp://hdl.handle.net/10754/209397en
dc.description.abstractSolvent vapor annealing has recently emerged as an intriguing, room-temperature, and highly versatile alternative to thermal annealing. The chemically selective interaction between solvents and organic semiconductors opens new opportunities to selectively anneal certain components of the device, while leaving others intact. On the downside, these interactions are complex and rather unpredictable, requiring further investigation. We propose a novel methodology to investigate solvent-film interactions, based on use of an in situ quartz crystal microbalance with dissipation (QCM-D) capability and in situ grazing incidence wide angle X-ray scattering (GIWAXS). These methods make it possible to investigate both qualitatively and quantitatively the solvent vapor uptake, the resulting softening and changes (reversible and/or irreversible) in crystallinity. Using this strategy, we have investigated the solvent vapor annealing of traditional donor and acceptor materials, namely poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-Phenyl-C61-butyric acid methyl ester (PCBM). We find these materials retain their rigid structure during toluene vapor annealing and do not dewet. We also investigated the toluene vapor annealing of several newly proposed acceptor molecules (pentacene-based) modified with various silyl groups and electron withdrawing groups to tune the packing structure of the acceptor domains and energy levels at the donor-acceptor interface. We found a dramatic effect of the electron-withdrawing group on vapor uptake and whether the film remains rigid, softens, or dissolves completely. In the case of trifluoromethyl electron-withdrawing group, we found the film dissolves, resulting in complete and irreversible loss of long range order. By contrast, the cyano group prevented loss of long range order, instead promoting crystallization in some cases. The silyl groups had a secondary effect in comparison to these. In the last part of the thesis, we investigated the toluene vapor annealing of P3HT-based blends. In general, the blend behavior was strongly affected by the choice of the acceptor. Nevertheless, the polymer mediated the outcome, maintaining the integrity of the blend and preventing dewetting altogether. The TIPS (silyl) substituted pentacene molecules consistently segregated from the blend and crystallized on the surface, revealing their incompatibility with P3HT.en
dc.language.isoenen
dc.titleEvaluation of the Process of Solvent Vapor Annealing on Organic Thin Filmsen
dc.typeThesisen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
thesis.degree.grantorKing Abdullah University of Science and Technologyen_GB
dc.contributor.committeememberBakr, Osmanen
dc.contributor.committeememberWang, Pengen
thesis.degree.disciplineChemical and Biological Engineeringen
thesis.degree.nameMaster of Scienceen
dc.person.id101883en
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