Use of Interfacial Interactions and Complexation of Carbon Dots to Construct Ultra‐Robust and Efficient Photothermal Film From Micro‐Carbonized Polysaccharides

Abstract Solar energy conversion technologies, particularly solar‐driven photothermal conversion, are both clean and manageable. Although much progress has been made in designing solar‐driven photothermal materials, significant challenges remain, not least the photobleaching of organic dyes. To tackle these issues, micro‐carbonized polysaccharide chains, with carbon dots (CDs) suspended from the chains, are conceived, just like grapes or tomatoes hanging from a vine. Carbonization of sodium carboxymethyl cellulose (CMC) produces just such a structure (termed CMC‐g‐CDs), which is used to produce an ultra‐stable, robust, and efficient solar‐thermal film by interfacial interactions within the CMC‐g‐CDs. The introduction of the CDs into the matrix of the photothermal material effectively avoided the problem of photobleaching. Manipulating the interfacial interactions (such as electrostatic interactions, van der Waals interactions, π–π stacking, and hydrogen bonding) between the CDs and the polymer chains markedly enhances the mechanical properties of the photothermal film. The CMC‐g‐CDs are complexed with Fe 3+ to eliminate leakage of the photothermal reagent from the matrix and to solve the problem of poor water resistance. The resulting film (CMC‐g‐CDs‐Fe) has excellent prospects for practical application as a photothermal film.