A selection rule of solvent for highly aligned diketopyrrolopyrrole-based conjugated polymer film for high performance organic field-effect transistors

• Published in: Organic electronics Vol. 55; pp. 6 - 14
• Main Authors: Kim, Nam-Koo, Shin, Eun-Sol, Noh, Yong-Young, Kim, Dong-Yu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2018
• Subjects: Conjugated polymer; Off-central coating; Organic field-effect transistor; Polymer alignment; Solvent effect; Solvent effect; Conjugated polymer; Organic field-effect transistor; Polymer alignment; Off-central coating
• ISSN: 1566-1199; 1878-5530
• DOI: 10.1016/j.orgel.2018.01.006

Controlling the morphology of conjugated polymer film through careful selection of solvent is very important for facilitating charge transport in organic opto-electrical and electrical devices. In this report, we systematically study on a selection rule for optimum solvent choice to achieve highly aligned conjugated polymer chains with large ordered domain sizes for high performance organic field-effect transistors (OFETs) through various experimental analysis and Hansen solubility parameters. Three parameters: boiling point, solubility, and molecular interaction between conjugated polymer and solvents, are the most important to obtain optimum morphology. Similar molecular interaction values between solvent and conjugated polymer determined the formation of larger size ordered domain in films. High boiling point and relatively poor solubility solvents affect anisotropic film formation of conjugated polymer chains during off-center spin-coating. Considering these, large ordered domains with highly aligned diketopyrrolopyrrole thieno[3,2-b]thiophene (DPPT-TT) polymer chains were achieved by these important factors, and we demonstrate impressively high field-effect mobility ∼5.89 cm2 V−1 s−1 with low standard deviation (13%), which is the highest reported value so far for top-gate/bottom-contact DPPT-TT OFETs. [Display omitted] •We study on a selection rule for optimum solvent for highly aligned conjugated polymer.•The highly aligned film is obtained by off-center spin coating of DPPT-TT in marginal solvent.•High mobility of 5.89 cm2 V−1 s−1 is achieved by diketopyrrolopyrrole based OFETs.