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CdSe/TiO2 core-shell nanoparticles produced in AOT reverse micelles: applications in pollutant photodegradation using visible light.

Fontes Garcia AM, Fernandes MS, Coutinho PJ - Nanoscale Res Lett (2011)

Bottom Line: CdSe quantum dots with a prominent band-edge photoluminescence were obtained by a soft AOT water-in-oil (w/o) microemulsion templating method with an estimated size of 2.7 nm.The CdSe particles were covered with a TiO2 layer using an intermediate SiO2 coupling reagent by a sol-gel process.The resulting CdSe/TiO2 core/shell nanoparticles showed appreciable photocatalytic activity at λ = 405 nm which can only originate because of electron injection from the conduction band of CdSe to that of TiO2.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre of Physics (CFUM), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal. pcoutinho@fisica.uminho.pt.

ABSTRACT
CdSe quantum dots with a prominent band-edge photoluminescence were obtained by a soft AOT water-in-oil (w/o) microemulsion templating method with an estimated size of 2.7 nm. The CdSe particles were covered with a TiO2 layer using an intermediate SiO2 coupling reagent by a sol-gel process. The resulting CdSe/TiO2 core/shell nanoparticles showed appreciable photocatalytic activity at λ = 405 nm which can only originate because of electron injection from the conduction band of CdSe to that of TiO2.

No MeSH data available.


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Absorption spectra of CdSe QDs and CdSe/TiO2 core-shell nanoparticles.
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Figure 3: Absorption spectra of CdSe QDs and CdSe/TiO2 core-shell nanoparticles.

Mentions: After the addition of the mixture of silicon and titanium alkoxides to the solution of CdSe QDs, the PL disappeared. This indicates that, upon hydrolysis of the alkoxides and covalent coupling through the SH group of MTMS, a mixed layer of SiO2 and TiO2 is formed above the CdSe nanoparticles. The strong quenching effect observed may be explained by the efficient electron transfer from excited CdSe to TiO2 conduction band reported previously [3]. The resulting solution was turbid so that the absorption spectra did not reveal the typical absorption peaks of CdSe. However, by means of reflection measurements of the particles in a capillary, it was possible to obtain the spectrum in Figure 3, which confirms the presence of CdSe nanoparticles with approximately the same size.


CdSe/TiO2 core-shell nanoparticles produced in AOT reverse micelles: applications in pollutant photodegradation using visible light.

Fontes Garcia AM, Fernandes MS, Coutinho PJ - Nanoscale Res Lett (2011)

Absorption spectra of CdSe QDs and CdSe/TiO2 core-shell nanoparticles.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211843&req=5

Figure 3: Absorption spectra of CdSe QDs and CdSe/TiO2 core-shell nanoparticles.
Mentions: After the addition of the mixture of silicon and titanium alkoxides to the solution of CdSe QDs, the PL disappeared. This indicates that, upon hydrolysis of the alkoxides and covalent coupling through the SH group of MTMS, a mixed layer of SiO2 and TiO2 is formed above the CdSe nanoparticles. The strong quenching effect observed may be explained by the efficient electron transfer from excited CdSe to TiO2 conduction band reported previously [3]. The resulting solution was turbid so that the absorption spectra did not reveal the typical absorption peaks of CdSe. However, by means of reflection measurements of the particles in a capillary, it was possible to obtain the spectrum in Figure 3, which confirms the presence of CdSe nanoparticles with approximately the same size.

Bottom Line: CdSe quantum dots with a prominent band-edge photoluminescence were obtained by a soft AOT water-in-oil (w/o) microemulsion templating method with an estimated size of 2.7 nm.The CdSe particles were covered with a TiO2 layer using an intermediate SiO2 coupling reagent by a sol-gel process.The resulting CdSe/TiO2 core/shell nanoparticles showed appreciable photocatalytic activity at λ = 405 nm which can only originate because of electron injection from the conduction band of CdSe to that of TiO2.

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre of Physics (CFUM), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal. pcoutinho@fisica.uminho.pt.

ABSTRACT
CdSe quantum dots with a prominent band-edge photoluminescence were obtained by a soft AOT water-in-oil (w/o) microemulsion templating method with an estimated size of 2.7 nm. The CdSe particles were covered with a TiO2 layer using an intermediate SiO2 coupling reagent by a sol-gel process. The resulting CdSe/TiO2 core/shell nanoparticles showed appreciable photocatalytic activity at λ = 405 nm which can only originate because of electron injection from the conduction band of CdSe to that of TiO2.

No MeSH data available.


Related in: MedlinePlus