Localized and Controllable Mineral Salts Crystallization Enabled by Dye Modified Gold Nanorods with Enhanced Photothermal Conversion

Abstract Well‐designed nanomaterials with favorable photothermal performance are beneficial for exploring fascinating and prospective applications. Herein the facile and effective way is reported to enhance photothermal properties of gold nanorods (GNRs) through immobilizing tailored organic dyes around GNRs. Benefitting from the combination of plasmonic thermalization and nonradiative relaxation, the modified GNRs exhibit a temperature increase of >100 °C under 638 nm laser irradiation in film state, which is double of that of the bare GNRs‐doped film under the same condition. The hybrid film also exhibits superior stability and reusability compared to the film only doped with the dyes. Surface temperature of the hybrid film can be adjusted from 31 to 116 °C by tunning either doping materials concentration or light power. Interestingly, the hybrid film serves as a reusable energy converter in confined and controllable photothermal crystallization of mineral salts. NaCl crystals can be arranged into different patterns by moving the laser probe during the crystallization. Microcrystals of CaCO 3 (calcite, vaterite, and aragonite), BaCO 3, and SrCO 3 are successfully obtained. It is believed that the as‐prepared materials as well as the demonstrated photothermal crystallization will contribute to the development of function‐led photothermal materials.