Thiophene-Fused-Heteroaromatic Diones as Promising NIR Reflectors for Radiative Cooling

Developing appropriate NIR-reflective materials to combat near–infrared (NIR) heat radiation (700–2500 nm) from sunlight, avoiding energy accumulation and reduce energy consumption, is important and highly desirable. In this research, four thiophene-fused-heteroaromatic diones were used as basic reflectors to investigate the relationship between their intrinsic molecular structures and NIR-reflective properties. The reflectance intensity can be readily tuned by adjusting the length of the appended aliphatic side chains, as well as the strength of the electron-donating groups. A methoxy-substituted thiophene-fused-heteroaromatic dione showed the best performance in reflecting NIR, and it was used as a coating for a model glass house. The comparison of the internal temperature difference relative to a control house was measured and the maximum temperature was 12 °C lower than that in the control house.