Direction‐Selectable Ultra‐Highly Oriented State of Donor–Acceptor Conjugated Polymer Induced by Slow Bar Coating Process. (8th July 2021)

• Record Type: Journal Article
• Authors: Yabuuchi, Yuta; Minowa, Yu; Kajii, Hirotake; Nagano, Shusaku; Fujii, Akihiko; Ozaki, Masanori
• Is Part Of: Advanced Electronic Materials. Volume 7:Number 9(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-07-08
• Subjects: bar coating -- molecular orientation -- printed electronics -- π‐conjugated polymer; Materials -- Electric properties -- Periodicals; Materials science -- Periodicals; Magnetic materials -- Periodicals; Electronic apparatus and appliances -- Periodicals; 537
• DOI: 10.1002/aelm.202100313
• Languages: English
• ISSNs: 2199-160X

Abstract

Abstract: The molecular orientation of π‐conjugated polymers is a significant factor for the electrical properties of polymer‐based printable devices, because π‐conjugated polymers exhibit a notable fast carrier transport property along their main chain. Although various coating processes are suggested, the challenge to realize high‐degree alignment by one‐step coating without pre‐ or post‐treatments still remains. In this paper, it is reported on the fabrication of an extremely highly aligned thin film by a slow bar coating process using a donor–acceptor π‐conjugated polymer with great aggregability. The 2D order parameter achieved is 0.9, which is the highest obtained among the alignment methods with a one‐step coating process. Furthermore, the direction of the main chain is selectively oriented parallel or perpendicular to the coating direction depending on the solution concentration with high orientation degree. This unique orientation phenomenon seems to be related to the nematic liquid crystallinity of poly[2, 5‐(2‐octyldodecyl)‐3, 6‐diketopyrrolopyrrole‐alt‐5, 5‐(2, 5‐di(thien‐2‐yl)thieno [3, 2‐b]thiophene)] aggregates formed by the slow coating process. The orientation dynamics is discussed by taking the structure and behavior of the aggregates in the solution into account. Abstract : A slow bar coating process realizes an extremely highly aligned thin film of a donor–acceptor π‐conjugated polymer. The alignment direction is selectable with high orientation degree either parallel or perpendicular to the coating direction depending on the solution concentration. This unique orientation phenomenon is discussed by taking the structure and behavior of the aggregates in the solution into account.