4-8 July 2016
Kramer Law building
Africa/Johannesburg timezone
Paper Review: Initial screening in progress
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Colloidal InSe nanostructures: effect of morphology on their chemical sensitivity to methanol and formaldehyde fumes

Presented by Ms. Mildred AIRO on 5 Jul 2016 from 14:20 to 14:40
Type: Oral Presentation
Track: Track A - Division for Physics of Condensed Matter and Materials

Abstract

Two morphologies of indium monoselenide nanocrystals have been obtained by varying reaction parameters (time and precursor concentration) during their colloidal synthesis. The synthesized nanostructures crystallized in the same phase, rhombohedral InSe. However, the different morphologies had an influence in the optical properties with the nanoparticles more blue shifted from bulk. Herein we report for the first time, on the synthesis and characterization of indium monoselenide nanoparticles and nanosheets and their application as chemical sensors. We investigate the effect of the different morphologies on methanol and formaldehyde sensing. Since sensing ability is related to the electronic structure, it was palpable that the different morphologies will bring about different results. The sensors fabricated using the InSe nanoparticles gave a good response to HCOH fumes and methanol vapour. The sensor also showed selectivity towards HCOH fumes by giving a better response compared to that of acetone and chloroform vapours. The sensors fabricated using the InSe nanosheets similarly gave good response towards HCOH; however it recovered half way. For the methanol detection using a similar device, the noise to signal ratio was relatively high. The operating temperature range for the InSe sensor devices was determined to be near room temperature. The sensors’ response was observed to decrease with increasing temperature from 30 °C – 90 °C. The low sensing abilities of the nanostructures observed could be attributed to the surface capping molecule (oleylamine) employed to stabilize the nanostructures during synthesis.

Award

Yes

Level

PhD

Supervisor

Nosipho Moloto, Nosipho.Moloto@wits.ac.za, University of the Witwatersrand.

Paper

No

Permission

Yes

Place

Location: Kramer Law building
Address: UCT Middle Campus Cape Town
Room: LT1


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