Figure 3
(a) XRD curves of F16CuPc films grown on SiO2 substrate with the thickness D = 30 nm, 70 nm and 120 nm, respectively. The main diffraction peaks show a gradual change in peak positions where new peaks at higher 2θ values emerge with increasing the film thickness. The fitted curves for the (002) diffraction peaks are shown as well. The left inset is the XRD data obtained between 30° and 32°. Increasing the film thickness not only changes the positions of (002) diffraction peak, but also a new diffraction peak emerges at 31.4°, indexed as (108). The right inset is the schematic of molecular arrangement of (00l) and (108) orientations. The diffraction peaks were indexed using single crystal data: a = 4.7960 Å, b = 10.228 Å, c = 28.002 Å, α = 86.41°, β = 87.89°, γ = 81.39° 24. (b) Schematic of F16CuPc molecular orientations in films as increasing the thickness D. The gaps between the grain boundaries or molecules become bigger as increasing the thickness D, in which it provides more probabilities that new molecules move into the gaps and arrange with new orientations. They aggregate, nucleate, grow up and accelerate the formation of nanobelt crystals.
