Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Zinc oxide nanowires in chemical bath on seeded substrates: Role of hexamine
2006 (English)In: Journal of Sol-Gel Science and Technology, ISSN 0928-0707, E-ISSN 1573-4846, Vol. 39, no 1, 49-56 p.Article in journal (Refereed) Published
Place, publisher, year, edition, pages
2006. Vol. 39, no 1, 49-56 p.
Identifiers
URN: urn:nbn:se:kth:diva-13234DOI: 10.1007/s10971-006-6969-yISI: 000239432100006OAI: oai:DiVA.org:kth-13234DiVA: diva2:322532
Note
QC20100614Available from: 2010-06-07 Created: 2010-06-07 Last updated: 2017-12-12Bibliographically approved
In thesis
1. Photochemical and Photoelectric Applications of II-VI Semiconductor Nanomaterials
Open this publication in new window or tab >>Photochemical and Photoelectric Applications of II-VI Semiconductor Nanomaterials
2010 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

In this work we investigated fabrication of semiconductor nanomaterials and evaluated their potential for photo-chemical and photovoltaic applications. We investigated two different II-VI semiconductor nanomaterial systems; (i) ZnO oriented nanowire arrays non-epitaxially grown from a substrate; and (ii) colloidal CdTe nanotetrapods synthesized by solution-based thermal decomposition of organo-metallic precursors. In both the cases our main focus has been optimizing material synthesis for improving potential applications based on photon-electron interactions.

We have studied the synthesis of vertically aligned ZnO nanowire arrays (NWA), by a wet chemical process on various substrates. The synthesis is based on epitaxial growth of ZnO seed-layer on a substrate in a chemical bath consisting of an aqueous solution of zinc nitrate and hexamethylenetetramine (HMT). We have suggested an additional role played by HMT during the synthesis of ZnO nanowire arrays. We have also extended this synthesis method to fabricate hierarchical nanostructures of nanofibers of poly-L-lactide acting as a substrate for the radially oriented growth of ZnO nanowires. The combination of high surface area of the nanofibrous substrate with the flexibility of the PLLA-ZnO hierarchical nanostructure enabled the proof-of-principle demonstration of a ‘continuous-flow’ water treatment system that could effectively decompose single and combination of known organic pollutants in water, as well as render common waterborne bacteria nonviable.

We have studied another chemical synthesis that is commonly used for size controlled synthesis of colloidal quantum dots, which was modified to obtain anisotropic nanocrystals mainly for CdE (E=S, Se, Te) compositions. In this work we demonstrate by use of oleic acid (instead of alkylphosphonic acids) it is possible to synthesize CdTe and CdSe nanotetrapods at much lower temperatures (~180 ºC) than what is commonly reported in the literature, with significantly different  formation mechanism in the low-temperature reaction.

Finally, we have performed preliminary photoconduction measurements with CdTe nanotetrapods using gold ‘nanogap’ electrodes fabricated in-house, and obtain up to 100 times enhancement in current levels in the I–V measurements under illumination with a white light source.

Place, publisher, year, edition, pages
Stockholm: KTH, 2010. v, 47 p.
Series
Trita-ICT/MAP AVH, ISSN 1653-7610 ; 2010:03
Keyword
ZnO, Nanowire arrays, Photocatalysis, Nanofibers, CdTe, Nanotetrapods, Ostwalds ripening, Photoconduction, Nano-gap electrodes
Identifiers
urn:nbn:se:kth:diva-12808 (URN)978-91-7415-624-9 (ISBN)
Presentation
2010-05-05, C2, Electrum, Isafjordsgatan 22, Kista, 10:30 (English)
Opponent
Supervisors
Note
QC20100607Available from: 2010-06-07 Created: 2010-05-11 Last updated: 2010-06-07Bibliographically approved
2. Fabrication and Photoelectrochemical Applications of II-VI Semiconductor Nanomaterials
Open this publication in new window or tab >>Fabrication and Photoelectrochemical Applications of II-VI Semiconductor Nanomaterials
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

In this work we investigated fabrication of semiconductor nanomaterials and evaluated their potential for photo-chemical and photovoltaic applications. We investigated different II-VI semiconductor nanomaterial systems; (i) ZnO oriented nanowire arrays non-epitaxially grown from a substrate; and (ii) colloidal CdE (E=Te,Se,S) quantum structures synthesized by solution-based thermal decomposition of organo-metallic precursors.

We have studied the synthesis of vertically aligned ZnO nanowire arrays (NWA), by a wet chemical process on various substrates. We have extended this method wherein nanofibers of poly-L-lactide act as a substrate for the radially oriented growth of ZnO nanowires. By combining the large surface area and the flexibility of the PLLA-ZnO hierarchical nanostructure we have shown the proof-of-principle demonstration of a ‘continuous-flow’ water treatment system to decompose known organic pollutants in water, as well as render common waterborne bacteria non-viable.

We have studied synthesis of colloidal quantum dots (QD), and show size, morphology and composition tailored nanocrystals for CdE (E=S, Se, Te) compositions. We have studied the influence of crystal growth habits of the nanocrtsyals on the final morphology. Furthermore we have synthesized core-shell, CdSe-CdS QDs with spherical and tetrahedral morphologies by varying the reaction conditions. We show that these core-shell quantum dots show quasi-type II characteristics, and demonstrate with I-V measurements, the spatial localization of the charge carriers in these hetero-nanocrystals. For this purpose, we developed hybrid materials consisting of the core-shell quantum dots with electron acceptors (ZnO nanowires) and hole acceptors (polymeric P3HT nanofibers).

In addition we have also compared the synthesis reaction when carried out with conventional heating and microwave-mediated heating. We find that the reaction is enhanced, and the yield is qualitatively better when using microwave induced heating.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2012. viii, 55 p.
Series
Trita-ICT/MAP AVH, ISSN 1653-7610 ; 2012:09
Keyword
ZnO, nanowire arrays, photocatalysis, CdTe, CdSe, CdS, nanotetrapods, nanotetrahedrons, photoconduction, nano-gap electrodes, Type-II QDs, P3HT nanofibers, microwave synthesis.
National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-95410 (URN)978-91-7501-382-4 (ISBN)
Public defence
2012-05-31, Sal/Hall C2, KTH-ICT Electrum, Isafjordsgatan-22, Kista, 10:00 (English)
Opponent
Supervisors
Note
QC 20120525Available from: 2012-05-25 Created: 2012-05-24 Last updated: 2012-05-25Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Dutta, Joydeep

Search in DiVA

By author/editor
Sugunan, AbhilashDutta, Joydeep
In the same journal
Journal of Sol-Gel Science and Technology

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 571 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf