Amine Adsorption in an Electron-Deficient MOF Enhances Photothermal Conversion and Water Evaporation Efficiency

The development of novel intermolecular electron-transfer materials for applications like near-infrared (NIR) photothermal conversion and seawater desalination still poses a major challenge. Perylenediimides (PDIs) are a well-known class of organic dyes characterized by their electron-deficient planar structure, ultrafast photoinduced electron transfer, and excellent charge separation capabilities, properties which support their extensive use in a wide range of fields. In this work, we report a PDI-based metal-organic framework, named Zn-PDI-Cl4, designed as a host framework electron-transfer material with excellent stability and tunability. Zn-PDI-Cl4 can be converted into radical anions (Zn-PDI-Cl4•-) in situ through photoinduced electron transfer, with adsorbed dimethylamine serving as the electron donor. This electron transfer enables enhanced NIR absorption and confers high stability to the radical anions, endowing the material with highly efficient photothermal conversion performance, favorable solar-to-water efficiency, and promising potential for solar-driven water evaporation applications. This work provides an effective strategy for designing novel photothermal conversion materials based on intermolecular electron transfer.