Synthesis and organic solar cell performance of BODIPY and coumarin functionalized SWCNT or graphene oxide nanomaterials

The synthesis and characterization of new hybrid materials based on reduced graphene oxide (rGO) or single walled carbon nanotubes (SWCNTs) covalently functionalized by 4,4-difluoro-8-(4-propynyloxy)-phenyl-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene (BODIPY) (2) or 7-(prop-2-yn-1-yloxy)-3-(3,4,5-trimethoxyphenyl)-coumarin (4) as light harvesting groups were described. The organic solar cell performances of these novel nanomaterials in P3HT:PCBM blend were investigated. These covalently bonded hybrid materials (Reduced graphene oxide:BODIPY (GB), reduced graphene oxide:Coumarin (GC), SWCNTs:BODIPY (CB) and SWCNTs:Coumarin (CC)) were prepared by azide-alkyne Huisgen cycloaddition (Click) reaction between azide bearing SWCNTs or rGO and terminal ethynyl functionalized BODIPY (2) or coumarin (4) derivatives. The formation of novel nanomaterials was confirmed by the FT-IR, UV-Vis and Raman spectroscopies and thermogravimetric analysis. The best performance on P3HT:PCBM organic solar cell was produced by SWCNTs:Coumarin (CC) hybrids which was coated on a indium tin oxide coated polyethylene terephthalate film (ITO-PET)). The reference device based on P3HT:PCBM blend without CC showed power conversion efficiency (PCE) of 1.16%, FF of 35% and short-circuit current density (Jsc) of 5.51 mA.cm-2. The reference device with CC hybrids within P3HT:PCBM blend increased the values significantly to 1.62% for PCE, 40% for FF and 6.8 mA.cm-2 for Jsc.