Charge Transfer Host−Guest Complexes Based on a CBPQT4+ and Dibenzotetrathiafulvalene for the Construction of Near-Infrared Photothermal Antibacterial Materials

Abstract Near-infrared (NIR) photothermal materials are of significant importance across various scientific and technological domains due to their efficient conversion of light energy into heat, finding broad applications in seawater desalination and photothermal therapy. In this study, we introduce a novel host−guest cocrystallization strategy for the preparation of NIR photothermal materials. Specifically, we utilize tetracationic cyclophane cyclobis(paraquat-p-phenylene) (CBPQT4+) and dibenzotetrathiafulvalene (DTTF) to form a 1:1 host−guest complex, denoted as CBPQT4+⊃DTTF. The robust charge-transfer interaction within this complex results in a narrowed bandgap and significant NIR absorption. Upon NIR laser illumination, the cocrystals exhibit a rapid and pronounced temperature elevation. Furthermore, the excellent photothermal effects endow the CBPQT4+⊃DTTF-dispersed solution with remarkable antimicrobial properties, making it a promising candidate for antimicrobial applications.