In-situ investigation of the formation of silver nanoparticles in polyvinyl alcohol through micro-Raman spectroscopy

In this publication, it is shown how to synthesize silver nanoparticles from silver cations out of aqueous solutions by the use of an atmospheric pressure plasma source. The use of an atmospheric pressure plasma leads to a very fast reduction of silver ions in extensive solvent volumes. In order to investigate the nanoparticle synthesis process, ultraviolet/visible (UV/VIS) absorption spectra were recorded in situ. By using transmission electron microscopy and by the analysis of UV/VIS spectra, the kinetics of silver nanoparticle formation by plasma influence can be seen in more detail. For example, there are two different sections visible in the synthesis during the plasma exposure process. The first section of the synthesis is characterized by a linear formation of small spherical particles of nearly constant size. The second section is predominated by saturation effects. Here, particle faults are increasingly formed, induced by changes in the particle shape and the fusion of those particles. The plasma exposure time, therefore, determines the shape and size distribution of the nanoparticles.

Download Full-text

Combined synchrotron x-ray diffraction and micro-Raman for following in situ the growth of solution-deposited YBa2Cu3O7 thin films

Journal of Materials Research ◽

10.1557/jmr.2005.0421 ◽

2005 ◽

Vol 20 (12) ◽

pp. 3270-3273 ◽

Cited By ~ 3

Author(s):

F. Berberich ◽

H. Graafsma ◽

B. Rousseau ◽

A. Canizares ◽

R. Ramy Ratiarison ◽

...

Keyword(s):

Raman Spectroscopy ◽

X Ray Diffraction ◽

X Ray ◽

Additional Information ◽

Micro Raman Spectroscopy ◽

High Temperature Process ◽

Structural Growth ◽

Metal Organic ◽

Insight Into

A unique combination of in situ synchrotron x-ray diffraction and in situ micro-Raman spectroscopy was used to study the growth process of YBa2Cu3O6+x films obtained by metal organic decomposition using trifluoroacetate precursor on LaAlO3 substrates. The techniques give complementary information: x-ray diffraction gives insight into the structural growth, whereas micro-Raman spectroscopy gives information of the chemical composition with additional information on the texture. To perform both experiments in situ, a special high-temperature process chamber was designed.

Download Full-text

Enhanced yield strength in iron nanocomposite with in situ grown single-wall carbon nanotubes

Journal of Materials Research ◽

10.1557/jmr.2006.0061 ◽

2006 ◽

Vol 21 (2) ◽

pp. 522-528 ◽

Cited By ~ 13

Author(s):

A. Goyal ◽

D.A. Wiegand ◽

F.J. Owens ◽

Z. Iqbal

Keyword(s):

Carbon Nanotubes ◽

Raman Spectroscopy ◽

Yield Strength ◽

Vapor Deposition ◽

Single Wall Carbon Nanotubes ◽

Iron Matrix ◽

Single Wall Carbon ◽

X Ray ◽

Micro Raman Spectroscopy

The yield strength of iron-carbon nanotube composites fabricated by in situ chemical vapor deposition of 2.2 vol% single-wall carbon nanotubes (SWNTs) inside an iron matrix showed substantial enhancement up to 45%, relative to that of similarly treated pure iron samples without carbon nanotubes of the same piece density. The work hardening coefficient and the Vickers hardness coefficient also significantly increased in these composites relative to the reference samples. X-ray diffraction together with energy dispersive x-ray measurements and micro-Raman spectroscopy indicated no concomitant formation of carbides and very little amorphous carbon during the vapor deposition process. Micro-Raman spectroscopy and scanning and transmission electron microscopy showed spectral signatures and images, respectively, indicating the formation and dispersion of SWNTs within the cavities of the iron matrix. It is suggested that the increased strength of the nanocomposites was due to the mechanical support provided to these cavities by the extremely strong SWNTs.

Download Full-text