In organic photovoltaics (OPVs), the traditional fullerene acceptors have limited tunability and stability, and they are very expensive. Non-fullerene acceptors (NFAs) have been developed to overcome these drawbacks. Aza-dipyrromethene (ADP) material Zn(L2)2 has been shown to perform well in OPV using Poly(3-hexylthiophene-2,5-diyl) or P3HT as a donor, with a PCE as high as 5.5%. To further tune the optoelectronic properties of the zinc complex, fluorinated derivatives Zn(1F-L2)2, Zn(2F-L2)2, and Zn(3F-L2)2 were synthesized, characterized, and tested in devices. Fluorination had a negligible effect on light absorption in both solution and film. Cyclic voltammetry indicates that fluorination decreased the HOMO energy levels slightly while not affecting LUMO energy levels. Results in OPVs show Zn(1F-L2)2 and Zn(3F-L2)2 have higher PCE but Zn(2F-L2)2 have lower PCE compared to Zn(L2)2. Charge recombination was tested for all the materials to study the PCE difference. These results are explained by film morphology observed by AFM and electron transport property of Zn(1F-L2)2, Zn(2F-L2)2, and Zn(3F-L2)2 materials.

Effect of fluorination on opto-electronic properties of zinc(II) di(naphthylethynyl)azadipyrromethene for organic photovoltaic applications

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.