Single‐Component Crosslinked Electro‐Optic Material with High Electro‐Optic Coefficient and Long‐Term Alignment Stability

Abstract Designing practical organic electro‐optic materials with both a high electro‐optic coefficient and high stability has always been a challenge in this field. To solve this problem, different types of crosslinkable functional groups are introduced into the donor and electron bridge of the crosslinkable single chromophores CY1‐CY3 with 4‐(Diethylamino)salicylaldehyde as the donor. Intramolecular anthracene‐acrylate and anthracene‐maleimide‐based Diels–Alder reaction and Azide−alkyne‐based Huisgen cycloaddition reaction can effectively improve the glass transition temperature and long‐term poling orientation stability of organic electro‐optic materials by converting small molecules into polymer materials. Electro‐optic coefficient as high as 211–221 pm V −1 at 1310 nm and glass transition temperature up to 157–185 °C is achieved in these crosslinked neat films CY1‐CY3 due to high chromophore density (4.93–5.4 × 10 20 molecules cm −3 ) and strong donor. Long‐term alignment stability tests showed that 94.54%–99.58% of the initial r 33 value can be maintained for poled crosslinked electro‐optic films CY1‐CY3 after heating at 85 °C for over 500 h. In addition, the single‐component crosslinking system avoids the problems of the ratio of binary crosslinking materials. In addition, the large electro‐optic coefficient and long‐term poling orientation stability make the single‐component crosslinking materials very promising for practical high‐performance electro‐optic modulators and other devices.