Stable Radical Anions from Perylenediimide-Functionalized Bispillar[5]arene for Boosting Near-Infrared Photothermal Conversion
Perylene diimide (PDI) radical anions exhibit poor environmental stability, restricting their generation efficiency and practical application. Here, a PDI-functionalized bispillar[5]arene (PDI-P5) was designed to construct stable and high-efficiency photothermal radicals. Intramolecular charge transfer (ICT) between PDI and bispillar[5]arene narrows the energy gap. Under 455 nm ultraviolet light irradiation and diethylamine (DEA) vapor exposure, photoinduced electron transfer (PET) efficiently generates PDI-P5·− radicals, which possess broad near-infrared (NIR) absorption, enhanced non-radiative transitions, and excellent stability. Notably, PDI-P5·− can rapidly reach 90 °C under 0.20 W cm−2 simulated sunlight irradiation. Moreover, it exhibits superior multi-step photothermal anti-counterfeiting performance. This work provides a novel strategy for the development of stable radical-based photothermal materials, which holds great potential for anti-counterfeiting and bioimaging applications.