Chern, Yaw-TerngYaw-TerngChernZeng, Shi-JunShi-JunZengLin, Yong-HsienYong-HsienLinShao, Yu-JenYu-JenShaoLin, Peng-YiPeng-YiLinZhong, Kai-ChengKai-ChengZhongChen, Jyh-ChienJyh-ChienChenGUEY-SHENG LIOU2025-11-172025-11-172025-10https://www.scopus.com/record/display.uri?eid=2-s2.0-105017784685&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/733711Triphenylamine (TPA)-based polymers have emerged as an attractive electrochromic (EC) material class because of their colorless neutral state and interesting EC behavior. The electrochemical stability of materials is a crucially important feature for the practical use of materials for any purpose. Herein, the concept of side-chain engineering involving incorporating multiple electroactive nitrogen atoms into redox-active polyamide P4 is successfully achieved by designing a new TPA-based diamine (4) with three electroactive nitrogen atoms, demonstrating a significant enhancement in EC stability. The resulting polymer P4 presents the second-highest EC stability compared to all other triarylamine-based polymers reported to date, with only 2.83 % decay in its coloration efficiency (CE) at 430 nm after 25,000 switching cycles at the first oxidation stage. P4 also exhibited highly integrated EC performances, including multiple color changes (from colorless to yellow, dark green, and navy blue), high contrast of optical transmittance change (ΔT (%) = 56.2 % at 430 nm at the first oxidation stage), excellent processing, and electrochemical stability. Notably, measuring the NIR absorption provides direct evidence of polaron delocalization, confirming that the EC stability of the material could be governed by electron resonance delocalized across all redox centers. By integrating this design principle, P4 achieves broad NIR absorption and outstanding stability, highlighting its potential for applications in smart windows, EC displays, and other high-performance optoelectronic devices.falseElectroactive nitrogen centerElectrochromic polyamidePolaronSide-chain engineering[SDGs]SDG7journal article10.1016/j.mtchem.2025.1031052-s2.0-105017784685