Synthesis, characterization and luminescence properties of Y-doped and Tb-doped ZnO nanocrystals

doi:10.1016/j.mseb.2009.04.004

Materials Science and Engineering: B

Volume 162, Issue 3, 15 June 2009, Pages 179-184

https://doi.org/10.1016/j.mseb.2009.04.004 Get rights and content

Abstract

A wet chemical route with calcination procedure was used to synthesize Y-doped and Tb-doped ZnO nanocrystals using Zn(NO₃)₂·6H₂O, Y(NO₃)₃·6H₂O, Tb(NO)₃·6H₂O and (NH₄)₂CO₃ as starting materials. The results of X-ray diffraction (XRD), combined X-ray photoelectron spectroscopy (XPS) and energy dispersion spectroscopy (EDS) indicated that Y and Tb were successfully doped into the crystal lattice of ZnO matrix. The field emission scanning electron microscopy (FESEM) results showed that pure ZnO had nanorod like morphology, whereas Y-doped and Tb–ZnO sample exhibited nanoflake and cluster like morphology, respectively. The luminescence properties of pure ZnO and doped ZnO samples were also investigated. The results showed that the strong UV emission peak of Y-doped and Tb-doped ZnO photoluminescence spectra exhibited a red shift compared with pure ZnO, which was ascribed to the defects and the formation of shallow energy level caused by the incorporation of Y and Tb dopants.

Introduction

Nanostructured materials have attracted considerable attention due to their potential applications in electronic, optical, optoelectronic and electrochemical devices [1], [2], [3], [4]. ZnO with wide bandgap (3.37 eV), large exciton binding energy (60 meV) at room temperature and excellent chemical and thermal stability [5], is considered to be an attractive phosphor for low voltage emissive displays. Additionally, it is universally regarded as an excellent host material for the doping of the rare earth and transition metal ions with optical and magnetic activity [6], [7], [8], [9], [10]. Doped ZnO nanocrystals are expected to exhibit an efficient visible emission and be appropriate for vacuum fluorescent displays and field emission displays. Previous studies rare about elements doped ZnO were reported and the photoluminescence (PL) properties were modified due to the introduction of dopants. Great efforts have been made to optimize the fabrication procedures and improve the luminescence efficiency of ZnO since it is very sensitive to synthesis conditions [11], [12], [13], [14], [15], [16].

In this work, pure ZnO, Y-doped and Tb-doped ZnO nanocrystals were synthesized by a wet chemical route along with calcination process and characterized by a series of measurements. The luminescence properties of the products were also investigated.

Section snippets

Experimental

All the starting materials were analytical grade and were used without further purification. Zinc nitrate hexhydrate (Zn(NO₃)₂·6H₂O), yttrium nitrate hexhydrate (Y(NO₃)₃·6H₂O) and terbium nitrate hexhydrate (Tb(NO₃)₃·6H₂O) were used as Zn, Y and Tb sources, respectively. The precipitate reagent was (NH₄)₂CO₃. Cetyltrimethyl–ammonium bromide (CTAB) was used as a surfactant for assisting the growth of nanocrystals. In a typical procedure, a certain amount of Zn(NO₃)₂·6H₂O (0.595 g) and (NH₄)₂CO₃

Results and discussion

The XRD patterns of pure ZnO, 4 at% Y-doped and 2 at% Tb-doped ZnO samples are shown in Fig. 1. The full-width at half maximum (FWHM) and lattice parameters of the samples are listed in Table 2. The diffraction peaks can be indexed to wurtzite ZnO and no other impurities phase is found in the products. However, it should be noted that the diffraction peaks of doped samples become broader compared with those of pure ZnO, which indicates a smaller size of doped ZnO nanocrystals. Furthermore, it is

Conclusions

Y-doped and Tb-doped ZnO nanocrystals with different morphology were successfully synthesized via a wet chemical route along with calcination procedure. The results of XRD, EDS and XPS reveal that Y and Tb ions are incorporated into ZnO and occupy Zn sites. Dopants ions have a remarkable effect on the Raman spectrum. The intensity of the peak, corresponding to the E₂ mode, decreases significantly compared with that of pure ZnO. The PL property of doped ZnO is modified due to the incorporation

Acknowledgements

The work was financially supported by the Ministry of Education of China (PCSIRT0644) and the National Science Foundation of China (A3 Foresight Project no.: 50821140308).

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Synthesis, characterization and luminescence properties of Y-doped and Tb-doped ZnO nanocrystals

Abstract

Introduction

Section snippets

Experimental

Results and discussion

Conclusions

Acknowledgements

Mater. Sci. Eng. A

Chem. Phys. Lett.

Phys. Lett. A

J. Lumin.

Photobiol A: Chem.

J. Catal.

J. Mol. Catal. A-Chem.

Mater. Lett.

J. Cryst. Growth

Appl. Surf. Sci.

Chem. Phys. Lett.

Science

Mater. Sci. Eng. A

Phys. Rev. Lett.