Electrodeposited Copolymers Based on 9,9'-(5-Bromo-1,3-phenylene)biscarbazole and Dithiophene Derivatives for High-Performance Electrochromic Devices

Chung-Wen Kuo; Jui-Cheng Chang; Jeng-Kuei Chang; Sheng-Wei Huang; Pei-Ying Lee; Tzi-Yi Wu

doi:10.3390/polym13071136

Electrodeposited Copolymers Based on 9,9'-(5-Bromo-1,3-phenylene)biscarbazole and Dithiophene Derivatives for High-Performance Electrochromic Devices

Polymers (Basel). 2021 Apr 2;13(7):1136. doi: 10.3390/polym13071136.

Authors

Chung-Wen Kuo¹, Jui-Cheng Chang^{2

3}, Jeng-Kuei Chang⁴, Sheng-Wei Huang¹, Pei-Ying Lee², Tzi-Yi Wu²

Affiliations

¹ Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 80778, Taiwan.
² Department of Chemical Engineering and Materials Engineering, National Yunlin University of Science and Technology, Yunlin 64002, Taiwan.
³ Bachelor Program in Interdisciplinary Studies, National Yunlin University of Science and Technology, Yunlin 64002, Taiwan.
⁴ Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, No. 1001 University Road, Hsinchu 30010, Taiwan.

Abstract

A 1,3-bis(carbazol-9-yl)benzene derivative (BPBC) was synthesized and its related homopolymer (PBPBC) and copolymers (P(BPBC-co-BT), P(BPBC-co-CDT), and P(BPBC-co-CDTK)) were prepared using electrochemical polymerization. Investigations of polymeric spectra showed that PBPBC film was grey, iron-grey, yellowish-grey, and greyish-green from the neutral to the oxidized state. P(BPBC-co-BT), P(BPBC-co-CDT), and P(BPBC-co-CDTK) films showed multicolor transitions from the reduced to the oxidized state. The transmittance change (ΔT) of PBPBC, P(BPBC-co-BT), P(BPBC-co-CDT), and P(BPBC-co-CDTK) films were 29.6% at 1040 nm, 44.4% at 1030 nm, 22.3% at 1050 nm, and 41.4% at 1070 nm. The coloration efficiency (η) of PBPBC and P(BPBC-co-CDTK) films were evaluated to be 140.3 cm² C^-1 at 1040 nm and 283.7 cm² C^-1 at 1070 nm, respectively. A P(BPBC-co-BT)/PEDOT electrochromic device (ECD) showed a large ΔT (36.2% at 625 nm) and a fast response time (less than 0.5 s), whereas a P(BPBC-co-CDTK)/PEDOT ECD revealed a large η (534.4 cm² C^-1 at 610 nm) and sufficient optical circuit memory.

Keywords: absorption spectra; electrochromic device; electrodeposition; redox stability; transmittance.