Unprecedented facile approach of multiple amino-substituted triphenylamine derivatives for electrochromic devices with extremely high coloration efficiency and unexpected redox stability

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 466; p. 143003
• Main Authors: Shao, Yu-Jen, Tu, Min-Hsiu, Liou, Guey-Sheng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.06.2023
• Subjects: Amino substituent; Electrochromism; High coloration efficiency; High stability; Triphenylamine derivatives; Electrochromism; Triphenylamine derivatives; Amino substituent; High stability; High coloration efficiency
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.143003

[Display omitted] •The stereotype of an unstable NH2 group for long-term electrochemistry is broken.•The more attached NH2 groups on the TPA unit show superior electrochromism.•The kinetics of the TPAs are well elucidated to prove the feasibility.•The coloration efficiency of TPA-3N/HV device can reach up to 631 cm2/C.•TPA-3N/HV shows remarkable retaining stability of 98% at on-state for 10 h. Generally, the amino group is considered highly reactive and unstable. Thus, the amino derivatives would be entirely consumed by polymerization or end-capping to preserve the material stability in most research or application fields. Herein, we demonstrated that triphenylamine (TPA) with multiple para-amino substituents could reduce oxidation potential and provide extra oxidation sites while retaining their reversibility. Four para-amino-substituted TPA derivatives (TPA-1N, TPA-2N, TPA-3N, and TPA-ADM) designed and prepared in this study exhibited excellent stability under the electrochemical redox procedure, revealing more than 88% reversibility in the continuous cyclic voltammetry process up to 10,000 cycles. Among all the electrochromic devices, TPA-3N/HV performs the highest coloration efficiency (631 cm2/C), coloration speed (46.4 % s−1), and superior stability, manifesting a reversibility of 99% or 98% after 1000 cycles (switching) or 10 h (maintaining at coloring state), respectively.