Scientific Results

Non-Plasmonic SERS with Silicon: Is It Really Safe? New Insights into the Optothermal Properties of Core/Shell Microbeads

Year: 2018

Authors: Bontempi N., Vassalini I., Danesi S., Ferroni M., Donarelli M., Colombi P., Alessandri I.

Autors Affiliation: [Bontempi, Nicolo; Vassalini, Irene; Danesi, Stefano; Alessandri, Ivano] INSTM UdR Brescia, Via Branze 38, I-25123 Brescia, Italy.
[Vassalini, Irene; Danesi, Stefano] Univ Brescia, Dept Mech & Ind Engn, Via Branze 38, I-25123 Brescia, Italy.
[Ferroni, Matteo; Alessandri, Ivano] Univ Brescia, Dept Informat Engn, Via Branze 38, I-25123 Brescia, Italy.
[Bontempi, Nicolo; Ferroni, Matteo] CNR, INO, Via Branze 38, I-25123 Brescia, Italy.
[Colombi, Paolo] CSMT, Via Branze 45, I-25123 Brescia, Italy

Abstract: Silicon is one of the most interesting candidates for plasmon-free surface-enhaced Raman scattering (SERS), because of its high-refractive index and thermal stability. However, here we demonstrate that the alleged thermal stability of silicon nanoshells irradiated by conventional Raman laser cannot be taken for granted. We investigated the opto-thermal behavior of SiO2/Si core/shell microbeads (Si-rex) irradiated with three common Raman laser sources (lambda = 532, 633, 78S nm) under real working conditions. We obtained an experimental proof of the critical role played by bead size and aggregation in heat and light management, demonstrating that, in the case of strong optothermal coupling, the temperature can exceed that of the melting points of both core and shell components. In addition, we also show that weakly coupled beads can be utilized as stable substrates for plasmon-free SERS experiments.

Journal/Review: THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS

Volume: 9 (9)      Pages from: 2127  to: 2132

More Information: Università degli Studi di Brescia. Regione Lombardia. – We thank Enrico Turrini (University of Brescia) for assistance in data elaboration. This work was carried out in the framework of the project: “Microsfere adattative per il monitoraggio e l’abbattimento di inquinanti persistenti-MI ADATTI E L’ABBATTI” supported by INSTM and Regione Lombardia.
KeyWords: Raman-scattering; field enhancement; nanoshells; surface; crystallization
DOI: 10.1021/acs.jpclett.8b00662

Citations: 7
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