Original small molecules with processing feasibility, structural diversity and fine-tuned properties are applied in interfacial solar water evaporation. However, the common defects of narrow solar absorption, low photothermal conversion efficiency and photobleaching result in limited materials available and unsatisfactory evaporation performance. Herein, the perylene diimide (PDI) derivatives are exploited as stable sunlight absorbers for high efficiency solar vapor generation. In particular, a stable PDI-DTMA is well-designed with donor-acceptor-donor configuration based on plane rigid PDI core. The efficient photothermal conversion is enabled via strong intermolecular π-π stacking and intramolecular charge transfer, which is revealed by experimental demonstration and theoretical calculation. The PDI-DTMA with narrow band gap of 1.17 eV exhibits expanded absorption spectrum and enhanced non-radiative transition capability. Based on this, the three dimensional hybrid hydrogels (PPHs) combining PDI-DTMA and polyvinyl alcohol are constructed. With the synergistic effect of solar-to-heat conversion, thermal localization management, water activation and unobstructed water transmission of PPHs, the high water evaporation rates can reach 3.61~10.07 kg m-2 h-1 under one sun. The hydrogels also possess great potential in seawater desalination and sewage treatment. This
work offers important insights into designing photothermal small organic molecules and showcases their potential in solar water evaporation systems.
