Understanding the Crystal Packing and Organic Thin‐Film Transistor Performance in Isomeric Guest–Host Systems. Issue 23 (12th April 2017)

• Record Type: Journal Article
• Authors: Hailey, Anna K.; Petty, Anthony J.; Washbourne, Jennifer; Thorley, Karl J.; Parkin, Sean R.; Anthony, John E.; Loo, Yueh‐Lin
• Is Part Of: Advanced materials. Volume 29:Issue 23(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-04-12
• Subjects: disorder -- guest–host systems -- isomers -- organic semiconductors -- organic thin‐film transistors; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201700048
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract : In order to understand how additives influence the structure and electrical properties of active layers in thin‐film devices, a compositionally identical but structurally different guest–host system based on the syn and anti isomers of triethylsilylethynyl anthradithiophene (TES ADT) is systematically explored. The mobility of organic thin‐film transistors (OTFTs) comprising anti TES ADT drops with the addition of only 0.01% of the syn isomer and is pinned at the mobility of OTFTs having pure syn isomer after the addition of only 10% of the isomer. As the syn isomer fraction increases, intermolecular repulsion increases, resulting in a decrease in the unit‐cell density and concomitant disordering of the charge‐transport pathway. This molecular disorder leads to an increase in charge trapping, causing the mobility of OTFTs to drop with increasing syn‐ isomer concentration. Since charge transport is sensitive to even minute fractions of molecular disorder, this work emphasizes the importance of prioritizing structural compatibility when choosing material pairs for guest–host systems. Abstract : The effect of molecular disorder on crystal packing and organic thin‐film transistor (OTFT) performance is systematically explored by adding the compositionally identical but structurally different syn isomer to its anti isomer of triethylsilylethynyl anthradithiophene. The addition of only 10% syn isomer introduces sufficient disorder and charge trapping to reduce device mobilities to the levels of OTFTs comprising pure syn isomer.