Photoinduced variations in the size of nanoparticles of CdS in colloidal solutions

Shvalagin, V. V.; Raevskaya, A. E.; Stroyuk, A. L.; Kuchmii, S. Ya.

doi:10.1007/s11237-007-0021-3

Cited by 4 publications

(5 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The photocatalytic reduction of elemental sulfur by alcohol on the surface of CdS nanoparticles in the presence of cadmium acetate leads to the deposition of an additional amount of CdS on it and to an increase in the average size of the nanoparticles [245]. It is seen from Fig.…”

Section: Photoinduced Increase Of the Size Of Semiconductor Nanopartimentioning

confidence: 83%

“…The method proposed in [69,70] for improving the electrical contact between the TiO 2 nanoparticles in the films by irradiating them after additional treatment with Ti IV complexes may prove to be of great practical importance. Of greatest importance, however, are the methods of reducing and increasing the size of the semiconductor nanoparticles examined in Section IV and also the approaches to narrowing the size distribution of the nanoparticles [230][231][232][233][234][235][236][237][238][239][240][241][242][243][244][245][250][251][252][253][254][255][256].…”

Section: Photochemical Change Of the Characteristics Of The Synthesizmentioning

confidence: 99%

See 1 more Smart Citation

Photochemical formation of semiconducting nanostructures

et al. 2008

Self Cite

View full text Add to dashboard Cite

Existing data on photochemical and photocatalytic approaches to the formation of semiconducting nanoparticles and also binary semiconducting nanostructures and nanocomposites of semiconductors with metals and polymers are reviewed. The nature of the effect of irradiation on the synthesis and properties of the obtained nanostructures and the possibility of photocatalytic control of the structural and spectral parameters of nanostructural semiconducting systems are examined.The accumulation of data on the properties of semiconducting (SC) nanomaterials, which has occurred particularly rapidly in the last 7-10 years, has opened up ever more alluring prospects for their application as light-sensitive and light-emitting components in nanophotonics [1-3], nanophotocatalysis [2,[4][5][6][7], biosensorics [8][9][10][11], and other important fields. The possibility of practical utilization is an important factor that has stimulated the search for and study of the processes involved in the formation of nanomaterials. On this account an enormous number of publications have now accumulated on the improvement of existing and development of new methods for the synthesis of semiconducting nanoparticles and nanostructures (e.g., see the reviews [6, 12-15]). A special position among them is occupied by methods based on photochemical transformations conducted either for the purpose of synthesis and directing it along a desired path or for improving the characteristics of nanostructures produced by other methods.Photochemical methods of synthesis have proved more effective than the production of nanomaterials by traditional synthetic approaches, and in a number of cases only they make it possible to achieve the assigned aim. For this reason the synthesis of semiconducting nanostructures and their modification under the conditions of photoirradiation are constantly attracting the attention of investigators, and the number of publications devoted to these questions is constantly increasing. We note, however, that they nevertheless remain disjointed.In view of the foregoing an attempt is made in the present article to organize existing data, to identify the most important directions for research and development, and thus to assess the current state of development of photochemical approaches to the formation of semiconducting nanostructures. Analysis of data on the photochemical formation and post-synthesis photochemical treatment of semiconducting nanostructures and multicomponent nanocomposites, including the nanoparticles of metals and polymers in addition to semiconductors, showed that in spite of the variety and diversity of the proposed approaches all the papers can be ascribed to only three courses: synthesis, synthesis control, and changing the characteristics of the semiconducting nanostructures. For this reason in this review photochemical approaches to the synthesis of nanoparticles of metal chalcogenides, binary semiconducting nanostructures, and nanocomposites consisting of semiconducting and conducting polymers are examin...

show abstract

Section: Photoinduced Increase Of the Size Of Semiconductor Nanopartimentioning

confidence: 83%

Section: Photochemical Change Of the Characteristics Of The Synthesizmentioning

confidence: 99%

Photochemical formation of semiconducting nanostructures

et al. 2008

Self Cite

View full text Add to dashboard Cite

show abstract

“…It is known that S 8 can be reduced photocatalytically by alcohol at the surface of CdS [9] and TiO 2 [10] nanoparticles. Comparison of the data set out above with these data gives reason to suppose that photocatalytic reduction of S 8 , followed by the formation of CdS, also occurs in this case: It was established that the quantum yield of the formation of cadmium sulfide F varies in the range of 0.02-0.03 with increase in the content of ZnO nanoparticles from 1·10 -3 to 1·10 -2 M and hardly depends at all on either the initial concentrations of Cd(CH 3 COO) 2 and S 8 or their ratio.…”

Section: Resultsmentioning

confidence: 99%

“…The rod-like crystals of ZnO probably fulfill the role of a unique template for the forming tubes, ensuring invariability in the geometry of the space in which photodeposition of the cadmium sulfide occurs. In [9] it was shown that CdS itself is capable of acting as a photocatalyst for the reduction of sulfur. However, if the formation of cadmium sulfide occurred not only at the zinc oxide but also at the previously deposited CdS, disruption of the directional growth of the nanotubes and distortion of their regular form would be expected.…”

Section: Resultsmentioning

confidence: 99%

“…The concentration of the cadmium sulfide formed and the quantum yield of the photocatalytic process F were determined by analysis of the spectral data using the molar extinction coefficient at wavelength 380 nm (e 380 = 1400 L×mol×cm -1 ), corresponding to the position of the isobestic point in the spectra of CdS nanoparticles of various sizes [9].…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Photocatalytic formation of porous CdS/ZnO nanospheres and CdS nanotubes

et al. 2007

Self Cite

View full text Add to dashboard Cite

It was found that ZnO nanocrystals have photocatalytic activity in the formation of CdS during the reduction of sulfur in the presence of cadmium acetate. It was shown that mesoporous spheres measuring 150-170 nm and consisting of CdS/ZnO particles measuring 5-8 nm are formed during the irradiation of ZnO particles measuring 5.5 nm. During the photodeposition of CdS by the action of light on nanorods produced by ultrasonic treatment of microcrystalline zinc oxide nanotubes of CdS 0.5-0.8 µm in length and 15-110 nm in internal diameter are formed. A mechanism, in which they appear at the ends of the ZnO nanorods and grow on the surface of the CdS/ZnO heterojunction, is proposed for the formation of the CdS nanotubes.The most important conditions for the successful functioning of photocatalytic systems based on semiconductor (SCR) materials are effective spatial separation of the unlike photogenerated charges and saturation of the semiconductor surface by the substrates of the photocatalytic reaction. The first of these conditions can be realized, for example, with the use of composite photocatalysts consisting of two or more semiconductors, electron mediators, dark-stage catalysts, etc.[1].The second condition can be met by the appropriate spatial arrangement of the semiconductor-photocatalyst. Analysis of publications of recent years shows that progress in this direction has been associated with the use of ordered micro-and mesoporous materials and also of hollow semiconducting spheres and, probably, nanotubes [2]. In such spatially arranged photocatalysts a "depo" effect appears, i.e., accumulation of the substrate molecules, making it possible to maintain a sufficiently high concentration of them in the surface layer of the semiconductor and thereby weakening the effect of the diffusion-kinetic complications characteristic of many photocatalytic processes. At the same time the fairly rigorous conditions for the production of such structures and, in particular, the need to use high temperatures at many stages of the synthesis restrict their range largely to oxide systems [2,3]. This may explain the very small number of publications on the synthesis of mesoporous and hollow nanostructures based on sulfide semiconductors with photocatalytic activity. Thus, the production of mesoporous CdS involves the use of structure-directing directing templates such as liquid-crystalline matrices [4]. Familiar methods for the production of CdS nanotubes such as, for example, deposition from the gas phase [5] and synthesis in the pores of aluminum membranes [6] and in micellar media [7] are also quite complicated and in most cases do not make it possible to obtain materials that could be used directly as photocatalysts.In the present work it was discovered that zinc oxide has photocatalytic activity in the formation of CdS. It was found that as a result of deliberately changing the conditions it was possible to achieve the formation both of mesoporous nanodimensional spheres, consisting of CdS/ZnO nanoparticles, and of cadmium s...

show abstract