Exceptional Second Near-Infrared Window Organic Photothermal Material for High-Temperature Applications Activated by a 1064 nm Laser

High-temperature photothermal response functional materials are an important branch of advanced photothermal materials. However, pure organic high-temperature photothermal materials are currently relatively scarce, and their molecular design and synthesis are challenging. In this research, a highly efficient [2 + 2] cycloaddition–retroelectrocyclization reaction has been carried out between the precursor molecule containing N,N-diphenyl-4-(phenylethynyl)aniline and piperazine-2,5-dione units (TP) and the typical electron-deficient unit 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (4F-TCNQ), and a rigid and twisted high-temperature photothermal organic material (named TTP) has been successfully designed and synthesized. This material is easy to synthesize and solution-processable, has broad spectral absorption (320–1900 nm), and can be triggered for high-temperature (∼400 °C) photothermal response by a near-infrared region II (NIR-II) laser (1064 nm). It has also been successfully applied to laser ignition, the construction of high-temperature shape memory actuators, and photowelding of metals with a 1064 nm laser, demonstrating the attractive potential for high-temperature NIR-II photothermal applications.