Asymmetric anionic [O⋯H⋯N]−1 -type strong H-bond constructed new near-infrared organic photothermal materials with high molar absorptivity and high amount of temperature rise

Abstract

The development of photothermal materials based on perylene diimide radical anion with air-stable and near-infrared strong absorption is still challenging. We report new near-infrared perylene diimide radical anion species with high molar absorptivity and high amount of temperature rise, which was stabilized by an asymmetric anionic [O⋯H⋯N]−1-type strong H-bond between oxygen in carbonyl of perylene diimide radicals and hydrogen in amine of branched polyethyleneimine. The introduction of branched polyethyleneimine not only makes hydrogen bonding compound has good water solubility, but also inhibits the aggregation and increases the stability of radicals through steric hindrance and hydrogen bond effect. This hydrogen bonding compound shows high amount of temperature rise achieved 32.1 °C at the concentration of 0.267 mM under 808 nm laser, and it is stable enough in air for several months. An asymmetric anionic [O⋯H⋯N]−1-type strong H-bond opens a new strategy to improve the stability of perylene diimide radicals in air and the photothermal performance.