A Processible and Ultrahigh‐temperature Organic Photothermal Material through Spontaneous and Quantitative [2+2] Cycloaddition–Cycloreversion

Energy conversion, particularly light to heat conversion, has garnered significant attention owing to its prospect in renewable energy exploitation and utilization. Most previous efforts have focused on developing organic photothermal materials for low‐temperature applications, whereas the importance of simplifying the preparation methods of photothermal materials and enhancing their maximum photothermal temperature have been less taken. Herein, we prepare an organic near‐infrared (NIR) photothermal material namely ATT by a spontaneous [2+2] cycloaddition‐cycloreversion reaction. In addition to the solution‐based method, ATT could also be readily preapred by ball milling in a high yield of 90% in just 15 min. ATT powder exhibits a broad absorption extending beyond 2000 nm, excellent processability, and thermal stability. Remarkably, ATT powder can reach an unprecedently temperature as high as 450 °C while maintaining excellent photostability upon photoirradiation. Leveraging its extraordinary photothermal and processable properties, ATT was used in the high‐temperature applications, such as photo‐ignition, photo‐controlled metal processing and high‐temperature shape memory, all of which offer spatiotemporal control capabilities. This work provides a new approach to prepare organic photothermal materials with high temperatures, and pave the way for their applications in extreme environments.