A simple synthesis route to CdS nanomaterials with different morphologies by sonochemical reduction
Introduction
The preparation of nanomaterials has drawn intensive interests during recent years due to their fundamental research and potential applications in electronics, optics, catalysis, etc. These properties and applications are usually largely dependent on the size, shape and impurities of the nanomaterials [1]. Therefore, development of shape-controlled synthesis is of great interest in materials science [2], [3], [4]. As one of the most important II–IV group semiconductors, CdS semiconductors with different structures have received considerable attention because of their special properties and critical applications, such as solar cells, quantum size effect semiconductor, optoelectronic and electronic devices, biological labeling [5], [6]. Great efforts have been made to fabricate CdS nanomaterials. CdS nanoparticles [7], [8], [9], nanofibrils, nanocables, nanowires [10], [11], [12], [13], [14], [15] and nanotube [16] have been prepared in recent years.
In this letter, CdS semiconductors with different morphologies were prepared by a sonochemical reduction of a mixture solution of CdSO4·8/3H2O, Na2S2O3·5H2O, (CH3)2CHOH and hydroxyethyl cellulose (HEC) in Ar atmosphere at room temperature. The as-obtained samples were characterized with XRD, TEM and XPS.
Section snippets
Experimental procedure
In a typical preparation procedure, 0.01 mol l−1 CdSO4·8/3H2O (AR grade) and 0.02 mol l−1 Na2S2O3·5H2O (AR grade) were firstly dissolved in a mixture solution containing 23 ml (CH3)2CHOH, 77 ml doubly distilled water and 1% HEC (Mw, 123,000) in a conical flask with a cover. Then the flask was put in a sonication bath. Before irradiation with a 40-kHz ultrasonic wave at 100-W output power at room temperature, the conical flask was purged with Ar gas to eliminate oxygen. The flask was cooled by
Results and discussion
Fig. 1 shows the typical XRD pattern of CdS sample produced using 0.05 mol l−1 CdSO4·8/3H2O, 0.1 mol l−1 Na2S2O3·5H2O and 1% HEC by sonochemical reduction for 7 h. All the three peaks, at about 26.72°, 44.1° and 52.08°, respectively, can be indexed as a cubic phase β-CdS, which are oriented along the (111), (220) and (311) directions and close to the reported values (JCPDS file No. 10-454). No peaks attributable to other phases were observed.
The chemical composition of the product was
Conclusions
In summary, different morphologies CdS nanocrystals were prepared by a sonochemical synthesis at room temperature. CdSO4·8/3H2O was used as a Cd2+ source and Na2S2O3·5H2O as an S2− source. The HEC acts as embedding materials and soft templates. When the concentrations of CdSO4·8/3H2O, Na2S2O3·5H2O and HEC are appropriate, the morphologies of CdS nanocrystals can exhibit nanoparticles, nanowires and dendritic-like shape.
Acknowledgments
This work was supported by the Ministry of Science and Technology of China (grant no. 1999064501) and the Nature Science Foundation of China (grant no. 10074064).
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