Crystallization Control of Organic Semiconductors during Meniscus-Guided Coating by Blending with Polymer Binder
Blom, Paul W. M.
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
Biological and Environmental Sciences and Engineering (BESE) Division
Materials Science and Engineering Program
KAUST Solar Center (KSC)
KAUST Grant NumberCRG_R2_13_BEAU_KAUST_1
Online Publication Date2018-10-16
Print Publication Date2018-12
Permanent link to this recordhttp://hdl.handle.net/10754/630640
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AbstractSmall molecule organic semiconductors (OSCs) suffer from their uncontrolled nucleation and growth during solution processing limiting their functionality in electronic devices. In this work, a new method is presented based on dip-coating a blend consisting of OSC and insulating polymer to control the crystallization of the active film for organic field-effect transistors. A small fraction of amorphous poly(methyl methacrylate) (PMMA) efficiently improves the crystallization of dip-coated small molecule OSCs, α,ω-dihexylquaterthiophene (DH4T) and diketopyrrolopyrrole-sexithiophene (DPP6T). The maximum charge carrier mobilities of dip-coated OSC:PMMA films are significantly higher than drop-cast blend ones and comparable with OSC single crystals. The high charge carrier mobility originates from a continuous alignment of the crystalline films and stratified OSC and PMMA layers. The improved crystallization is attributed to two mechanisms: first, the polymer binder leads to a viscosity gradient at the meniscus during dip-coating, facilitating the draw of solute and thus mass transport. Second, the polymer binder solidifies at the bottom layer, reducing the nucleation barrier height of small molecule OSC. The findings demonstrate that a small fraction of a polymer binder during dip-coating efficiently improves the crystallization as well as the electronic properties of small molecule OSC films.
CitationZhang K, Marszalek T, Wucher P, Wang Z, Veith L, et al. (2018) Crystallization Control of Organic Semiconductors during Meniscus-Guided Coating by Blending with Polymer Binder. Advanced Functional Materials 28: 1805594. Available: http://dx.doi.org/10.1002/adfm.201805594.
SponsorsThe authors declare no competing financial interest. K.Z. thanks the China Scholarship Council (CSC) for financial support. T.M. acknowledges the Foundation for Polish Science cofinanced by the European Union under the European Regional Development Fund (First TEAM/2017–3/26). W.P. acknowledges the National Science Centre, Poland, through the grant UMO-2015/18/E/ST3/00322. P.M.B. acknowledges concurrent support from the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under Award No. CRG_R2_13_BEAU_KAUST_1 and under Baseline Research Funding. P.W. thanks the KAUST analytical core lab (ACL) for technical support in the mass spectrometry analyses. Z.W. acknowledges the support by European Research Council (ERC) (SmartPhon No. 694977).
JournalAdvanced Functional Materials