Green Photothermal Ink for 0D to 3D Solar‐Driven Devices

Abstract Photothermal materials as well as their forms and structures play a crucial role in the performance and applications of solar‐driven devices. There is a growing demand for low‐cost, easy‐to‐shape, and eco‐friendly photothermal materials to meet sustainable development. Therefore, a green photothermal ink with excellent photothermal capacity and highly accessible via Chinese ink and alginate is proposed. This photothermal ink can be easily fabricated and shaped into 0D to 3D (e.g., granules, fibers, films/felts, and sponges) solar‐driven devices by simple processes. Among them, the photothermal sponge displays excellent evaporation performance in solar desalination with an evaporation rate of 1.44 kg m −2 h −1 under one solar irradiation. The photothermal felt can accelerate ice melting and absorb the melted ice and prevent the substrate from freezing again. The photothermal granules can capture the moisture from the humid air and release the absorbed water under sunlight. The present photothermal ink provides a good strategy for solar‐driven devices in different practical applications.