Complex ZnO Nanotree Arrays with Tunable Top, Stem and Branch Structures

Transcription

1 Supporting Information Complex ZnO Nanotree Arrays with Tunable Top, Stem and Branch Structures Fenghua Zhao, JianGuo Zheng, Xianfeng Yang, Xiuyang Li, Jing Wang, Fuli Zhao, Kam Sing Wong, Chaolun Liang and Mingmei Wu* * To whom correspondence should be addressed 1

2 (c) (b) (a) Intensity / a.u X Zn ZnO 1011 Zn 1010 Zn Zn Theta / deg. Fig. S1 Powder XRD patterns (Cu Kα radiation, λ= nm) of the typical films grown at 140 o C for (a) 1.0, (b) 5.0, (c) 10 hours by direct hydrothermal oxidation of zinc foils. In (a), a peak with larger dspacing of 7.79 Å in the enlarged part (blue one) reveals the existence of a possible Znamine complex as described extensively in literatures and weak ZnO related peaks imply the small amount of ZnO; In (c), the strong 0002 peak indicates a highly oriented growth along caxis, which is consistent with the SEM images in Figure 1 while in (b) the fact that the ratio of 0002 and 1010 peak intensities is much smaller than that in (c) means the ZnO stem axes are not so oriented at this stage (see Fig. 6) as those in Fig. 1. 2

3 Fig. S2 (a, b) Low magnification SEM images of the branched ZnO forest prepared under the same condition as Figure 1, displaying root parts in crevices. The stem diameter is in the range of µm and the length can reach 25 µm which might be the longest dendritic ZnO nanostructures observed so far. (c) High magnification SEM image of a single branched ZnO tree, showing clear crosssections of the branches on a { 1010 } side surface. These branches are inclined to the substrate. An entire ZnO tree with a noncentric morphology from root to top may be related to P6 3 mc space group. 3

4 Supplementary Material (ESI) for Nanoscale Fig. S3 (a) A mediate magnification SEM image. (b) An enlargement of the white square indicated in (a), showing a typical smooth bladelike branch and its connection to the core stem on the side surface. Fig. S4 High resolution TEM (HRTEM) image of the nanorods at the top surface. The insert is a whole view of the top surface and an electron diffraction pattern from the nanorod arrays showing the same growth direction as the stem body. 4

5 Supplementary Material (ESI) for Nanoscale Fig. S5 SEM images of ZnO sample prepared at 180 oc for 10 h with en concentration of 3.75 mol L1. 5

6 Fig. S6 (a) Crosssection SEM image of a ZnO mushroom and (b, c) two enlargements, indicating that the ZnO mushroom with sixfold symmetry is coalesced by several branched ZnO trees with hexagonal prismatic stems. Both aligned primary and the secondary branches are clearly observed in the enlargement. 6

7 Supplementary Material (ESI) for Nanoscale Fig. S7 (a) Topview SEM image of ZnO mushrooms forming a large scale film prepared under the same growth conditions as Fig. 7. (b) A crevice of the film showing much smaller ZnO structures below the film surface. (c) The side view of the ZnO complex with bushy branches arrays pointing out from the side surfaces. 7

8 Intensity (a.u.) Theta/deg. Fig. S8 Powder XRD pattern of the product in Figure 8. The pattern is composed of ZnO and Zn metal. Intensity / a.u Theta/deg. Fig. S9 Powder XRD pattern of the product in Figure 10. The pattern is composed of ZnO and Zn metal. 8

9 Fig. S10 A typical colored SEM image of the ZnO film like coral reef grown from the reaction solution with more high concentration of en. (Note: The fish and the three fivepointedstars are added manually to have a lively but fictitious undersea world.) 9