New Mechanism for Long Photo-Induced Enhanced Raman Spectroscopy in Au Nanoparticles Embedded in TiO 2 .

Autor: Brognara A; Dipartimento di Energia, Micro and Nanostructured Materials Laboratory, Politecnico di Milano, via Ponzio 34/3, Milano, I-20133, Italy.; Department of Structure and Nano/-Micromechanics of Materials, Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40237, Düsseldorf, Germany., Bricchi BR; Dipartimento di Energia, Micro and Nanostructured Materials Laboratory, Politecnico di Milano, via Ponzio 34/3, Milano, I-20133, Italy., William L; Laboratoire des Sciences des Procédés et des Matériaux (LSPM), CNRS, Université Sorbonne Paris Nord, Villetaneuse, 93430, France., Brinza O; Laboratoire des Sciences des Procédés et des Matériaux (LSPM), CNRS, Université Sorbonne Paris Nord, Villetaneuse, 93430, France., Konstantakopoulou M; Laboratoire des Sciences des Procédés et des Matériaux (LSPM), CNRS, Université Sorbonne Paris Nord, Villetaneuse, 93430, France., Bassi AL; Dipartimento di Energia, Micro and Nanostructured Materials Laboratory, Politecnico di Milano, via Ponzio 34/3, Milano, I-20133, Italy., Ghidelli M; Dipartimento di Energia, Micro and Nanostructured Materials Laboratory, Politecnico di Milano, via Ponzio 34/3, Milano, I-20133, Italy.; Department of Structure and Nano/-Micromechanics of Materials, Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40237, Düsseldorf, Germany.; Laboratoire des Sciences des Procédés et des Matériaux (LSPM), CNRS, Université Sorbonne Paris Nord, Villetaneuse, 93430, France., Lidgi-Guigui N; Laboratoire des Sciences des Procédés et des Matériaux (LSPM), CNRS, Université Sorbonne Paris Nord, Villetaneuse, 93430, France.
Jazyk: angličtina
Zdroj: Small (Weinheim an der Bergstrasse, Germany) [Small] 2022 Jun; Vol. 18 (25), pp. e2201088. Date of Electronic Publication: 2022 May 26.
DOI: 10.1002/smll.202201088
Abstrakt: The photo-induced enhanced Raman spectroscopy (PIERS) effect is a phenomenon taking place when plasmonic nanoparticles deposited on a semiconductor are illuminated by UV light prior to Raman measurement. Results from the literature show that the PIERS effect lasts for about an hour. The proposed mechanism for this effect is the creation of oxygen vacancies in the semiconductor that would create a path for charge transfer between the analyte and the nanoparticles. However, this hypothesis has never been confirmed experimentally. Furthermore, the tested structure of the PIERS substrate has always been composed of plasmonic nanoparticles deposited on top of the semiconductor. Here, gold nanoparticles co-deposited with porous TiO 2 are used as a PIERS substrate. The deposition process confers the nanoparticles a unique position half buried in the nanoporous semiconductor. The resulting PIERS intensity is among the highest measured until now but most importantly the duration of the effect is significantly longer (at least 8 days). Cathodoluminescence measurements on these samples show that two distinct mechanisms are at stake for co-deposited and drop-casted gold nanoparticles. The oxygen vacancies hypothesis tends to be confirmed for the latter, but the narrowing of the depletion zone explains the long PIERS effect.
(© 2022 Wiley-VCH GmbH.)
Databáze: MEDLINE
Externí odkaz: