Fig. 1.

AFM images of GO (A) and GO-BNN6 (B), their height histograms (C), the molecular illustration (D) of the formation of GO-BNN6 via the π-π stacking between GO and BNN6, and FT-IR spectra (E) of GO, BNN6 and GO-BNN6 where three green areas indicate the characteristic bands of BNN6.