Relation between Spherulitic Growth, Molecular Organization, and Charge Carrier Transport in Meniscus‐Guided Coated Organic Semiconducting Films. (23rd June 2021)

• Record Type: Journal Article
• Authors: Zhang, Ke; Borkowski, Michal; Wucher, Philipp; Beaujuge, Pierre M.; Michels, Jasper J.; Blom, Paul. W. M.; Marszalek, Tomasz; Pisula, Wojciech
• Is Part Of: Advanced Electronic Materials. Volume 7:Number 8(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-06-23
• Subjects: charge carrier transport -- domain growth -- field‐effect transistor -- meniscus‐guided coating -- organic semiconductor; Materials -- Electric properties -- Periodicals; Materials science -- Periodicals; Magnetic materials -- Periodicals; Electronic apparatus and appliances -- Periodicals; 537
• DOI: 10.1002/aelm.202100397
• Languages: English
• ISSNs: 2199-160X

Abstract

Abstract: Meniscus‐guided coating (MGC) is an efficient and promising route to grow small molecule and polymer organic semiconductors (OSCs) into highly ordered and uniaxially orientated thin films for electronic applications. In this work, the impact of domain size and molecular order on the charge carrier transport in field‐effect transistors for a molecular organic semiconductor 4‐tolyl‐bithiophenyl‐diketopyrrolopyrrole (DPP(Th2 Bn)2 ) is investigated. The spherulitic domain growth of DPP(Th2 Bn)2 in thin films is controlled in the evaporative regime of zone‐casting by varying the substrate velocity. The decrease of coating velocity leads to a lower nucleation density and larger domain size of DPP(Th2 Bn)2 . At sufficiently low velocity, the spherulitic domains first elongate and then uniaxially grow in the coating direction. Although at the same time the molecular order decreases due to higher film thickness, the charge carrier transport improves for larger domain size and reduced density of boundaries in the transistor channel. These results provide insight on the relation between domain growth, molecular organization, and charge carrier transport in zone‐cast OSC thin films that are important for the upscaling of the technique for practical applications. Abstract : The size and orientation of spherulitic domains in thin zone‐cast films of a diketopyrrolopyrrole‐based molecular semiconductor increase with decreasing the coating velocity in the evaporative regime. Although at the same time the molecular order decreases due to higher film thickness, the charge carrier transport in field‐effect transistors improves due to larger domain size and reduced density of boundaries.