A “green” all-organic heterostructure functionalized by self-assembled fullerene small molecule with enhanced photocatalytic activity

• All organic PC 71 BM/g-C 3 N 4 photocatalysts were constructed by in situ self-assembly. • The heterostructures possess satisfactory biocompatibility. • The PC 71 BM served as the electron acceptor and photosensitizer. • · O 2 - acted as the main active species in the degradation process. Photocatalysis has been reported as a potential water purification technology for combating the pathogenic bacteria and degrading the hazardous chemicals. The photoactive organic semiconductors as the emerging class of an alternative to the traditional developed inorganic semiconductors are being widely pursued due to their tunable structures and low toxicity. Herein, the all-organic [6] , [6] -phenyl C 71 butyric acid methyl ester (PC 71 BM)/g-C 3 N 4 heterostructure have been created by introducing self-assembled n-type fullerene small molecule to the g-C 3 N 4 surface in situ . The absorption edge of the heterostructures with PC 71 BM as the photosensitizer extend from 450 to 650 nm. Moreover, the charge separation and transfer efficiencies of the photocatalysts are greatly promoted even with 1.0% amount of PC 71 BM because of its low reorganization energy and high reduction potential. All of these superiorities endow the heterostructures with over 99.7% antibacterial rates toward E. coli and S. aureus and excellent performance against their biofilms after irradiation for 135 and 180 min, respectively. Additionally, the heterostructures achieve excellent photocatalytic degradation ability for Rhodamine B and tetracycline. Importantly, the in vitro experiments reveal that the as-prepared heterostructures possess satisfactory biocompatibility and their toxicity is negligible. This study provides a new perspective for designing ecofriendly all-organic heterostructures with high photocatalytic activity.