Morphology and optoelectronic characteristics of organic field-effect transistors based on blends of polylactic acid and poly(3-hexylthiophene). Issue 10 (October 2018)

• Record Type: Journal Article
• Authors: Cho, Chia-Jung; Chen, Shu-Yuan; Kuo, Chi-Ching; Veeramuthu, Loganathan; Au-Duong, Ai-Nhan; Chiu, Yu-Cheng; Chang, Shang-Hung
• Is Part Of: Polymer journal. Volume 50:Issue 10(2018:Oct.)
• Page Start: 975
• Page End: 987
• Publication Date: 2018-10
• Subjects: Polymers -- Periodicals; 547.7
• DOI: 10.1038/s41428-018-0087-x
• Languages: English
• ISSNs: 0032-3896

Abstract

Abstract This study investigates the influence of the solvent used to prepare films of a poly(3-hexylthiophene) (P3HT) and poly(lactic acid) (PLA) blend on the morphology and charge transport mobility of field-effect transistors (FETs). Films prepared from CH2 Cl2, a poor solvent for P3HT, tended to form well-defined nanowires, attributable to P3HT self-assembly via a solubility-induced process. This phenomenon resulted in a mobility of 5.30 × 10−3 cm2 (Vs)−1 and an on/off ratio of 3.23 × 103 in a CH2 Cl2 -solvent P3HT/PLA-blend system with a P3HT content of 10 wt%. Even a blend with 2 wt% P3HT exhibited a mobility of 1.76 × 10−3 cm2 (Vs)−1 . However, in blend systems where CHCl3 solvent was employed in film preparation, the mobility decreased as the PLA content increased, and almost no electrical characteristics were exhibited at 50 wt% P3HT due to the isolated, spherical, phase-separated morphology of P3HT aggregation. Moreover, in CH2 Cl2 solvent systems, the mobility of the P3HT/PLA (10/90) blend decreased from 5.3 × 10−3 cm2 (Vs)−1 (in a glove box) to 3.7 × 10−3 cm2 (Vs)−1 (after 28 days of air exposure), whereas that of 100 wt% P3HT declined by approximately one order of magnitude. These results confirm that P3HT/PLA blends prepared from CH2 Cl2 solvent can be used to fabricate environmentally friendly, low-cost FETs with favorable air stability. The morphology and effects on the OFET performance of blends of various ratios of P3HT and insulating PLA using CHCl3 and CH2 Cl2 as solvents were explored. It is demonstrated that a P3HT network structure within the PLA matrix could be induced using CH2 Cl2 . The one-dimensional nanowire morphology of these network structures may have provided an efficient pathway for OFET charge transport. These results confirm that P3HT/PLA blends in CH2 Cl2 solvent could be used to fabricate low-cost, green-polymer-blended FETs.