Constructing ultra-stable photothermal plastics assisted by carbon dots with photocaged reactivity

Photothermal materials, especially photothermal plastics, are crucial building blocks for functional devices. Covalently immobilizing the photothermal carbon dots in plastic matrix is a promising method for producing efficient photothermal plastics. However, the reactive moieties of photothermal carbon dots are often destroyed because of harsh preparation conditions, preventing their covalent interaction with plastic matrix. Here, we conceptualized carbon dots with photocaged reactivity (P-CDs) for producing ultra-stable photothermal plastics. During the formation of P-CDs, hydroxyl moieties were maintained in the preparation environment. Upon UV irradiation, hydroxyl moieties of P-CDs were in situ converted into aldehyde groups and reacted with amino groups in the polysaccharide matrix, producing P-CD plastics. As-obtained P-CD plastics showed strong stability against solution immersion and UV aging. In particular, the P-CD plastics showed a high photothermal conversion efficiency of 46.6%. Such efficient and robust photothermal P-CD plastics were further applied to prepare a solar-driven thermoelectric generator (TEG) for energy generation.