Wang ZSun YLin SWang GChang XGou XLiu TJin SHe GWei Y.-CPI-TAI CHOUFang Y.2022-12-142022-12-14202116747291https://www.scopus.com/inward/record.uri?eid=2-s2.0-85118825267&doi=10.1007%2fs11426-021-1154-0&partnerID=40&md5=14fec216367b3f700ba8b407b0ea6d03https://scholars.lib.ntu.edu.tw/handle/123456789/626322Integrating multiple photosensitive properties into an “all-in-one” photosensitizer (PS) shows great promise for the treatment of cancers owing to synergistic effect among them. However, the development of such PSs, especially those that need a single laser source, remains a challenge. Herein, we report an orchestration of electron donors and acceptors in a propeller-like pentad, PBI-4Cz, where four carbazole (Cz) units are covalently linked to the ortho-positions of the perylene bisimide (PBI) core. Strong intramolecular donor-acceptor interaction significantly quenches the luminescence and largely extends the absorption spectra to near-infrared region. Excited-state dynamics investigated via femto- and nano-second transient absorption spectroscopy revealed exclusive charge separation of the PBI-4Cz within initial 0.5 ps when photoexcited regardless of which intermediate is involved. Energy dissipation of the resulting charge-separated state (PBI•−-4Cz•−) is subjected to the toggle between intersystem-crossing toward excited triplet states and charge recombination toward ground states. Relative importance of the two pathways can be tuned by micro-environmental polarity, which endows PBI-4Cz remarkable performances of singlet-oxygen generation (>90.0%) in toluene and photothermal conversion (∼28.6%) in DMSO. Harnessing intrinsic photostability and excited-state processes of heavy-atom-free PBI derivatives not only holds a promise for multifunctional phototheranostics, but also provides a prototype for designing high-performance PSs with tunable photoconversion pathways. [Figure not available: see fulltext.] © 2021, Science China Press and Springer-Verlag GmbH Germany, part of Springer Nature.charge recombination; charge separation; perylene bisimide derivatives; photosensitizers; singlet oxygen generation[SDGs]SDG3Absorption spectroscopy; Energy dissipation; Excited states; Gas generators; Ground state; Infrared devices; Oxygen; Polycyclic aromatic hydrocarbons; Separation; Charge recombinations; Charge-separation; Excitation state; Performance; Perylene bisimide derivative; Perylene bisimides; Photoconversion; Photosensitiser; Singlet oxygen generation; Tunables; Photosensitizersjournal article10.1007/s11426-021-1154-02-s2.0-85118825267