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Scientific article
English

Electron transfer across the germanium–polyelectrolyte–gold nanoparticle interface: convenient detection and applications in sensing

Contributors

Ghosh, Harekrishna; Bouhekka, Ahmed; Buergi, Thomas

Published in

PCCP. Physical chemistry chemical physics, vol. 18, no. 38, p. 26942-26948

Publication date

2016

Abstract

Germanium – polyelectrolyte – gold nanoparticle composites were prepared and characterized using FTIR-ATR spectroscopy and scanning electron microscopy. The germanium (Ge) element served as internal reflection element and the buildup of the layered system was followed in situ. Positively charged polyelectrolyte poly (allylamine hydrochloride) (PAH) adsorbs spontaneously on negatively charged Ge. Citrate-stabilized gold nanoparticles can then be adsorbed onto the PAH layer. Upon illumination of the device with visible light a prominent absorption over the entire mid infrared region is observed which is due to intervalence band transitions in Ge. The strong infrared signals are evidence for holes in the valence band of the Ge semiconductor, which arise due to electron transfer to the gold nanoparticles (GNP). The electron transfer, as evidenced by the holes in Ge, is affected by the nature of the gap between the Ge and the GNP. Increasing the gap by adsorbing polyelectrolyte multilayers hinders the electron transfer. Also heating and vacuum have a pronounced effect. The device is proposed as a sensor, where the sensing event is transduced into an optical signal in the infrared, as demonstrated for a thiol molecule. The thiol has a large affinity for the gold and therefore affects the germanium – gold nanoparticle gap. This reduces the electron transfer and therefore the absorption in the infrared upon illumination with visible light. Removal of the thiol from the solution leads to a recovering of the signal.

UNIGE affiliation entities

UNIGE research groups

Citation (ISO format)

GHOSH, Harekrishna, BOUHEKKA, Ahmed, BUERGI, Thomas. Electron transfer across the germanium–polyelectrolyte–gold nanoparticle interface: convenient detection and applications in sensing. In: PCCP. Physical chemistry chemical physics, 2016, vol. 18, n° 38, p. 26942–26948. doi: 10.1039/C6CP05098K

Main files (1)

Article (Published version)

Identifiers

Additional URL for this publication

http://xlink.rsc.org/?DOI=C6CP05098K

Journal ISSN

1463-9076
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Technical informations

Creation

30/09/2016 08:44:00

First validation

30/09/2016 08:44:00

Update

15/03/2023 00:47:27

Status update

15/03/2023 00:47:26

Last indexation

31/10/2024 04:39:05
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