Preparation and photoluminescence of γ-CuI nanoparticles

doi:10.1016/j.matlet.2005.12.093

Materials Letters

Volume 60, Issues 17–18, August 2006, Pages 2184-2186

https://doi.org/10.1016/j.matlet.2005.12.093 Get rights and content

Abstract

γ-CuI nanoparticles have been successfully prepared via a simple complex compound method, using a mixture of de-ionized water/ethanol as reaction medium at room temperature. X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence spectroscopy were used to characterize the samples. The results show that the diameter of the as-prepared CuI is about 30–40 nm and the fluorescence spectrum with a strong emission peak at 417 nm is observed. The possible mechanism of the formation of CuI nanoparticles is discussed.

Introduction

Recently, Cuprous Iodine (CuI) has attached much attention because of its unusual feathers such as large band gap, a negative spin-orbit splitting, an unusually large temperature dependency, anomalous diamagnetism behavior, a large ionicity, new high pressure phase etc [1], [2] and potential applications in superionic conductor, solid-state solar cells, catalysis for synthesis of organic compounds, etc [3], [4], [5]. CuI is a water-insoluble solid with three crystalline phases: γ-CuI below 350 °C, β-CuI between 392 and 350 °C, α-CuI above 392 °C. α-phase of cubic structure is a mixed conductor, which the carrier is predominantly Cu²⁺. The hexagonal β-phase is also an ions conductor [6], [7]. The low temperature γ-phase with zinc-blende structure is one of a few kinds of p-type semiconductors with a high band gap 3.1 eV [8].

CuI has been prepared in a variety of ways. CuI films can be formed by iodination of Cu films [9] or prepared with pulse laser deposition technique [10]. γ-CuI nanocrystals have been synthesized by an ethanol thermal method [3]. Ming Yang et al. developed a novel route to synthesize porous spherical CuI nanoparticles [5]. β-CuI were fabricated by a hybrid electrochemical/chemical method [11]. In order to find an easier method, in this paper, we reported a simple route to synthesize γ-CuI nanoparticles at room temperature. The mixture of water and ethanol acted as the solvent. As far as we know, CuI nanoparticles prepared by this method have not been reported. The possible mechanism of the formation of CuI nanoparticles is discussed.

Section snippets

Experimental

CuI nanoparticles were synthesized by a simple complex compound method. CuCl₂·2H₂O (A.R.), KI (A.R.) and Na₂SO₃ (A.R.) were used as starting materials. All chemicals were used without further purification. CuI nanoparticles were prepared by the following experimental sequence:

First, CuI precipitation was obtained by mixing the solutions of CuCl₂ and KI/Na₂SO₃, the precipitation was filtered, washed and dried. Then, the CuI was dissolved in a dense solution of KI using the mixture of water and

Results and discussion

The XRD pattern of sample-1 is shown in Fig. 1. The diffraction peaks corresponded to (111), (200), (220), (311), (400) and (331) planes of crystalline γ-CuI, respectively. No characteristic peaks of other phases are observed, suggesting that a pure γ-CuI compound exists. The lattice constant (a) calculated from the XRD data is 6.062 Å, which is in agreement with the reported data on JCPDS card (NO. 6-246, a = 6.051).

Fig. 2 presents the morphology and size distribution of CuI samples. It is

Conclusion

γ-CuI nanoparticles with a diameter about 30–40 nm were successfully synthesized by a simple complex compound method. The mixture of water and ethanol was the reaction medium. Ethanol played an important role in the synthesis process. From the emission spectrum, a strong emission peak at 417 nm was observed.

Acknowledgements

The authors are grateful for the awarded funds to excellent State Key Laboratory by Chinese Ministry of Education (No. 50323006).

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Preparation and photoluminescence of γ-CuI nanoparticles

Abstract

Introduction

Section snippets

Experimental

Results and discussion

Conclusion

Acknowledgements

Mater. Chem. Phys.

Mater. Sci. Eng., B, Solid-State Mater. Adv. Technol.

Sol. Energy Mater. Sol. Cells

Inorg. Chem. Commun.

Sol. Energy Mater. Sol. Cells

J. Lumin.

Chem. Phys. Lett.