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Proceedings Paper

Gallium nanoparticles colloids synthesis for UV bio-optical sensors
Author(s): Flavio Nucciarelli; Iria Bravo; Luis Vázquez; Encarnación Lorenzo; Jose Luis Pau
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Paper Abstract

A new method for the synthesis of colloidal gallium nanoparticles (Ga NPs) based on the thermal evaporation of Ga on an expendable aluminum zinc oxide (AZO) layer is presented here. The growth of AZO layers was investigated on different substrates at room temperature and 300 °C. By means of physical evaporation process, nanoparticles were deposited with a distribution ranging from 10 nm to 80 nm in diameter. A study of their endurance in acidic environment was carried out in order to assure the NPs shape and size stability during the etching process. Smaller particles start to disappear between 1h and 2h immersion time in a pH=1 solution, while bigger particles reduce their dimension. The NPs were dispersed in tetrahydrofuran (THF) organic solvent and optically characterized, showing strong UV absorption with a band centered at 280 nm. The colloids size distribution of as-evaporated samples was compared with the distribution obtained in droplets of the solution after drop-casting. By Dipole Discrete Approximation simulations, a close relationship between the UV absorption and the NPs with diameter smaller than ~40 nm was found. Because of the gallium oxide (Ga1-xOx) outer shell that surrounds the Ga NPs, an enhancement of their hydrophobicity occurs. Hence, the low agglomeration state between NPs in tetrahydrofuran allows to obtain narrow absorption band in the optical spectrum.

Paper Details

Date Published: 16 May 2017
PDF: 7 pages
Proc. SPIE 10231, Optical Sensors 2017, 1023127 (16 May 2017); doi: 10.1117/12.2265883
Show Author Affiliations
Flavio Nucciarelli, Univ. Autónoma de Madrid (Spain)
Iria Bravo, Univ. Autónoma de Madrid (Spain)
Luis Vázquez, Instituto de Ciencia de Materiales de Madrid (Spain)
Encarnación Lorenzo, Univ. Autónoma de Madrid (Spain)
Jose Luis Pau, Univ. Autónoma de Madrid (Spain)


Published in SPIE Proceedings Vol. 10231:
Optical Sensors 2017
Francesco Baldini; Jiri Homola; Robert A. Lieberman, Editor(s)

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