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Abstract
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Crystallization of poly[bis(triiso-propylsilylethynyl) benzodithiophene-bis(decyltetradecyl-thien) naphthobisthiadiazole]
(PBDT-TIPS-DTNT-DT) was investigated in supramolecules based on carbon nanotubes (CNTs) and reduced graphene oxide
(rGO) and their grafted derivatives. The principal peaks of PBDT-TIPS-DTNT-DT crystals were in the range 3.50∘ –3.75∘.
By grafting the surface of the carbonic materials, the assembling of polymer chains decreased because of hindrance of
poly(3-dodecylthiophene) (PDDT) grafts against �-stacking. The diameters of CNT/polymer and CNT-g-PDDT/polymer
supramolecules were 160 and 100 nm. The rGO/polymer supramolecules had the highest melting point (Tm = 282 ∘C) and
fusion enthalpy (�Hm = 25.98 J g−1), reflecting the largest crystallites and the most ordered constituents. Nano-hybrids based
on grafted rGO (276 ∘C and 28.26 J g−1), CNT (275 ∘C and 27.32 J g−1) and grafted CNT (268 ∘C and 22.17 J g−1) were also analyzed. Tm and �Hm values were significantly less in corresponding melt-grown systems. The nanostructures were incorporated
in active layers of PBDT-TIPS-DTNT-DT:phenyl-C71-butyric acid methyl ester (PC71BM) solar cells to improve the photovoltaic
features. The best results were detected for PBDT-TIPS-DTNT-DT:PC
71BM:rGO/polymer systems having Jsc = 13.11 mA cm−2,
fill factor 60% and V
oc = 0.71 V with an efficacy of 5.58%. On grafting the rGO and CNT, efficiency reductions were 12.01%
(5.58%–4.91%) and 9.34% (4.07%–3.69%), respectively.
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