Coordination-Induced NIR Photothermal Conversion and Laser Detonation Based on a Quasi-Diamond Interpenetrated Structure

In this work, a copper-based coordination polymer of [Cu₃(dhba)₂(OH)₂(H₂O)₄] (Cu-dhba, H₂dhba = 3,5-dinitro-4-hydroxybenzoic acid) has been constructed by the crystal-engineering approach, featuring a three-dimensional quasi-diamond interpenetrated structure. Impressively, due to the introduction of the d-d transition of the Cu²⁺ ion, Cu-dhba shows a broad absorption band with the maximum centered at the NIR section. As a result, Cu-dhba exhibits a remarkable photothermal conversion performance under 808 nm light; the temperature of the sample surface could be increased up to 115 °C within seconds. Benefiting from its high structure density and abundant hydrogen-bonding interactions, Cu-dhba shows no obvious performance decay after several photothermal cycling experiments. Moreover, due to the high density of energetic nitro groups periodically confined in its structure, Cu-dhba exhibits a drastic explosion under 808 nm laser irradiation, making Cu-dhba a promising laser-responsive energetic material.