Chinese Ink: A Powerful Photothermal Material for Solar Steam Generation

Abstract Solar steam generation holds great promise in alleviating fresh water crises, particularly in regions with accessible seawater and abundant insolation. Affordable, efficient, and environmentally friendly photothermal materials are needed to fabricate sunlight‐driven evaporation devices. Herein, Chinese ink, a carbon‐based paint used in traditional painting and calligraphy, is readily coated on diverse substrates and stabilized by atomic layer deposition (ALD) for solar steam generation. The ALD/Chinese ink coating exhibits strong and broad light absorption from the NIR to UV regions. Both ALD/Chinese‐ink‐coated membranes and wood display excellent photothermal properties and superior evaporation performance under simulated sunlight. This study demonstrates the potential of ALD/Chinese ink coating to achieve higher evaporation rate and efficiency by utilizing substrates with rough, structured surfaces and low thermal conductivity.