<i>In situ</i> polymerization of PEDOT:PSS films based on EMI-TFSI and the analysis of electrochromic performance
Haiyun Jiang, Wei Wu, Zigong Chang, Hailan Zeng, Ronglian Liang, Weiran Zhang, Weili Zhang, Guohua Wu, Ziyu Li, Haifei Wang
Abstract
Abstract In this report, PEDOT composite films were prepared by in situ electrochemical polymerization. 1-Ethyl-3-methylimidazole bis(trifluoromethylsulfonyl)imide (EMI-TFSI) was used as an ionic liquid dopant for PEDOT:PSS films. Subsequently, these PEDOT:PSS/EMI-TFSI films were compared with PEDOT:PSS films based on their morphology, structure, electrochromic properties, and optical properties at different deposition voltages and deposition times. It was observed that the addition of EMI-TFSI enhanced all the aforementioned properties of the films. PEDOT:PSS/EMI-TFSI films were seen to have a larger ion diffusion coefficient (1.38 × 10 −20 cm 2 ·s −1 ), a wider color change range (43.48%), a shorter response time (coloring response time = 1.2 s; fade response time = 2 s), and a higher coloring efficiency (189.86 cm 2 ·C −1 ) when compared with normal PEDOT:PSS films. The introduction of EMI-TFSI in the films ultimately resulted in superior electrochemical and optical properties along with higher stability.