All Organic Bulk Heterojunction Antibacterial Nanoparticles Prepared by Conjugated Donor Polymer and ITIC Acceptor

Abstract

PFO-DDQ is a donor−acceptor (D–A) type conjugated polymer, with its backbone consisting of 95% 9,9-di-octylfluorene (DOF) and 5% 2,3-dimethyl-5,8-dithien-2-yl-quinoxalines (DDQ). PFO-DDQ nanoparticles (NPs) suspensions are prepared using the nanoprecipitation method by varying the precursor solution concentration. The photoluminescence (PL) spectrum of the nanoparticles is determined by the energy transfer between the fluorene and the narrow-bandgap DDQ segments. The fluorescence of the NPs can be tuned from orange to blue by adjusting the concentration of the precursor solution. PFO-DDQ, the nonfullerene acceptor small molecule (ITIC), and PFO-DDQ/ITIC bulk heterojunction (BHJ) NPs suspensions are prepared using the nanoprecipitation method, and their photocatalytic antibacterial properties are evaluated. The results showed that, under 2 h of exposure to a 35 mW cm⁻² LED light, the antimicrobial rates of the three 40 µg mL⁻¹ nanoparticles suspensions against Escherichia coli (E. coli) are 98.28%, 100%, and 99.88%, respectively. The enhanced light absorption, improved charge transfer efficiency, and the crystalline phase of ITIC contributed to the faster photocatalytic antibacterial rate of PFO-DDQ/ITIC BHJ nanoparticles.