Photonic crystals in biology

Poster Session, Tuesday, June 15
Theme A1 - B702
Synthesis of ZnO nanorods by a simple Hydrothermal method
Leili Motevalizadeh * 1 ; Zahra Heidary * 1 ; Nasser Shahtahmassebi 2
1 Department of Physics, Faculty of Sciences, Islamic Azad University, Mashhad branch, Mashhad, Iran
2 Department of Physics, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad 91775-1436, Iran
Abstract- ZnO nanorods have been synthesized in low temperature by a novel simple hydrothermal method without using any substrates,
catalysts and autoclave. The samples have been characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD
patterns confirm that the prepared ZnO powders with different time reaction have the single-phase Wurtzite structure. SEM images show that the
sample was in the form of ZnO nanorods, with the average lengths of 2-3 μm and diameters of 200-400 nm.
In recent years studies on one-dimensional (1-D)
nanostructures such as nanotubes, nanowires, and nanorods
have received increasing attention because of their great
potential applications in the fields of scanning microscopes
and sensors [1], field emission devices [2], biological probes
[3] , and nanoelectronics [4].
ZnO is one of the most important materials due to its
large band gap energy of 3.37 eV and large exciton binding
energy of 60 meV at room temperature [5]. One-dimensional
ZnO nanostructures have attracted considerable interest
because of their promising applications in nanoscale
optoelectronic devices [6]. For preparation of 1-D ZnO
nanostructures various approach such as chemical vapor
deposition (CVD) [7], thermal evaporation [8], and pulsed
laser deposition (PLD) [9] have been reported. Recently,
Ashfold reported the preparation of 1-D ZnO nanostructures
via hydrothermal method [10, 11].
In this paper we reported the synthesis of ZnO nanorods
via the hydrothermal method at low temperature (90 ºC)
without using autoclave, catalysts, and templates. Aqueous
solution of deionized water, zinc chloride and ammonia (25%)
were prepared. The mixture solution transferred into closed
balloon in presence of nitrogen gas. the balloon was Sealed
and heated in an oil bath at 90°C for (a) 5 h, (b) 10 h, (c) 15 h,
respectively. After this stage, the balloon was cooled down to
room temperature. Following carefully washing with
deionized water and drying at 40°C under air atmosphere, the
white precipitates were collected, and kept for advance
characterization.
Figure 1 shows X-ray diffraction patterns from final
products with different reaction time. It is observed that all of
the diffraction peaks match the hexagonal ZnO structure with
lattice constants of a=b=3.249 Å and c=5.206 Å.
Figure 2 shows the SEM images of the products. A
comparison between SEM images reveals that with the
increase of reaction time initial nanoclusters (Fig. 2-a) divide
into uniform nanorods. By analysis of SEM images (Fig. 2-b,
Fig. 2-c) it is found that the average diameter of fabricated
ZnO nanorods is around 250 nm and their length is around 2.5
μm.
In summary, we synthesized ZnO nanorods via a simple
hydrothermal method without using autoclave. XRD analysis
confirmed the formation of hexagonal ZnO structure. SEM
images showed that the length and diameter of nanorods were
2-3 m and 200-400 nm, respectively. Meanwhile, had
synthesized ZnO nanorods with a diameter of 70 nm using
Intensity (a.u.)
Intensity (a.u.)
Intensity (a.u.)
0.8
0.6
0.4
0.2
1
0.8
0.6
0.4
0.2
0
1
0.8
0.6
0.4
0.2
0
1
0
(a)
20 30 40 50 60
2 0
(b)
20 30 40 50 60 70 80
2 0
(c)
20 30 40 50 60 70 80
2 0
Fig. 1: X-ray diffraction patterns from
final products with different reaction
time, (a) 5h, (b) 10h, (c) 15h.
autoclave [12]. The difference between our nanorods diameter
and that of Ref. [12] is due to different ambient pressure in the
two synthesis processes.
*Corresponding authors: lmotevali@mshdiau.ac.ir, z.heidary.62@gmail.com
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[3] G.I. Dovbeshko et al; Chem. Phys. Lett. 372 (2003) 432.
[4] S.J. Tans, R.M. Verschueren, C. Dekker, Nature 393 (1998) 49.
[5] M. Willander et al; Superlattices and Microstructures, 43 (2008) 352.
[6] C.R. Gorla et al; J.Appl. Phys. 85 (1999) 2595.
[7] J.J.Wu, S.C. Liu, Adv. Mater. 14 (2002) 215.
[8] X. Kong et al; Materials Chemistry and Physics; 82 (2003) 997.
[9] Ye. Sun et al; Chemical Physics Letters; 396, (2004) 21.
[10] M.N.R. Ashfold et al; Chem. Phys. Lett. 431 (2006) 352.
[11] M.N.R. Ashfold et al; Adv. Mater. 17 (2005) 2477.
[12] J. H. Yang et al; Cryst. Res.Technol. 44 (2009) 87.
(a)
(b)
(c)
Fig. 2: SEM images of ZnO
nanorods prepared with
different reaction time, (a) 5h,
(b) 10h, (c) 15h.
6th Nanoscience and Nanotechnology Conference, zmir, 2010 377