Chen Weilong, Liu Taili, Zou Jie, Zhang Di, Tse Man Kit, Tsang Sai-Wing, Luo Jingdong, Jen Alex K-Y
Shenzhen Research Institute, City University of Hong Kong, Shenzhen, 518057, China.
Department of Chemistry, City University of Hong Kong, Hong Kong SAR, 999077, China.
Adv Mater. 2024 Apr;36(17):e2306089. doi: 10.1002/adma.202306089. Epub 2023 Dec 2.
Harnessing the quadratic electro-optic (QEO) of near-infrared polymethine chromophores over broad telecom wavelength bands is a subject of immense potential but remains largely under-investigated. Herein a series of push-pull heptamethines containing the tricyanofuran (TCF) acceptors and indoline or benzo[e]indoline donors are reported. These dipolar chromophores can attain a highly delocalized "cyanine-like" electronic ground state in solvents spanning a wide range of polarities, in some cases even closer to the ideal polymethine state than symmetrical cyanines. A transmission-mode electromodulation spectroscopy is used to study the electric-field-induced changes in optical absorption and refraction of polymer films doped with heptamethine chromophores, and large and thermally stable QEO effect with high efficiency-loss figure-of-merits that compare favorably to those from dipolar polyenes in poled or unpoled polymers and III-V semiconductors is obtained. The study opens a path for developing organic materials based on cyanine-like merocyanines for complementary metal oxide semiconductor -compatible, fast, efficient, and low-loss electro-optic modulation.
在广泛的电信波长波段利用近红外聚甲炔发色团的二次电光效应（QEO）具有巨大潜力，但在很大程度上仍未得到充分研究。本文报道了一系列含有三氰基呋喃（TCF）受体和吲哚啉或苯并[e]吲哚啉供体的推拉型七甲川。这些偶极发色团在极性范围广泛的溶剂中可达到高度离域的“类花菁”电子基态，在某些情况下甚至比对称花菁更接近理想的聚甲炔状态。利用透射模式电调制光谱研究了掺杂七甲川发色团的聚合物薄膜中电场诱导的光吸收和折射变化，并获得了大的、热稳定的QEO效应，其具有高效率损耗品质因数，与极化或未极化聚合物及III-V族半导体中的偶极多烯相比具有优势。该研究为开发基于类花菁部花青的有机材料用于互补金属氧化物半导体兼容、快速、高效和低损耗电光调制开辟了一条道路。
