Applications of Electrochromic Copolymers Based on Tris(4-carbazoyl-9-ylphenyl)amine and Bithiophene Derivatives in Electrochromic Devices

Chung-Wen Kuo; Jui-Cheng Chang; Po-Ying Lee; Tzi-Yi Wu; Yu-Chang Huang

doi:10.3390/ma11101895

Applications of Electrochromic Copolymers Based on Tris(4-carbazoyl-9-ylphenyl)amine and Bithiophene Derivatives in Electrochromic Devices

Materials (Basel). 2018 Oct 3;11(10):1895. doi: 10.3390/ma11101895.

Authors

Chung-Wen Kuo¹, Jui-Cheng Chang², Po-Ying Lee³, Tzi-Yi Wu⁴, Yu-Chang Huang⁵

Affiliations

¹ Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 80778, Taiwan. welly@nkust.edu.tw.
² Bachelor Program in Interdisciplinary Studies, National Yunlin University of Science and Technology, Yunlin 64002, Taiwan. d700215@gmail.com.
³ Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 80778, Taiwan. k40017105@gcloud.csu.edu.tw.
⁴ Department of Chemical Engineering and Materials Engineering, National Yunlin University of Science and Technology, Yunlin 64002, Taiwan. wuty@gemail.yuntech.edu.tw.
⁵ Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, Kaohsiung 80778, Taiwan. ych@nkust.edu.tw.

Abstract

Four copolymers (P(tCz (tris(4-carbazoyl-9-ylphenyl)amine)-co-bTP (2,2'-bithiophene)), P(tCz-co-CPDT (4H-cyclopenta[2,1-b:3,4-b']dithiophene)), P(tCz-co-DTC (3,6-di(2-thienyl)carbazole)), and P(tCz-co-CPDTK (cyclopentadithiophene ketone))) are deposited on indium tin oxide (ITO) surfaces using electrochemical polymerization. Spectroelectrochemical properties of copolymer electrodes reveal that the colors of P(tCz-co-bTP) film are pinkish-orange, light olive green, light grayish blue, and dark blue at 0.0, 0.8, 1.2, and 1.6 V, respectively, whereas the color variations of P(tCz-co-CPDTK) film are light yellow, yellow, and blue at 0.0 V, 0.8 V, and 1.5 V, respectively. The ΔT of P(tCz-co-bTP), P(tCz-co-CPDT), P(tCz-co-DTC), and P(tCz-co-CPDTK) films are estimated to be 43.0% at 967 nm, 28.7% at 864 nm, 43.6% at 870 nm, and 24.5% at 984 nm, respectively. Five electrochromic devices (ECDs) are assembled using the tCz-based homopolymer and copolymers as coloring electrodes, and poly(2,2-dimethyl-3,4-propylenedioxythiophene) (PProDOT-Me₂) as the complementary electrode. P(tCz-co-DTC)/PProDOT-Me₂ ECD reveals high transmittance change (45.9% at 624 nm), P(tCz-co-CPDTK)/PProDOT-Me₂ ECD shows high η (513.0 cm² C^-1 at 582 nm), and P(tCz-co-bTP)/PProDOT-Me₂ ECD presents short switching time (less than 0.4 s) at 628 nm. Moreover, these ECDs show satisfactory redox stability and open circuit stability.

Keywords: copolymer; electrochemical polymerization; electrochromic device; redox stability; spectroelectrochemistry.