Dynamic Behavior of Surface-Enhanced Raman Spectra for Rhodamine 6G Interacting with Gold Nanorods: Implication for Analyses under Wet versus Dry Conditions

Author(s)

de Barros, Anerise ^[1] ; Shimizu, Flavio Makoto ^[2] ; de Oliveira, Cristine Santos ^[1] ; Sigoli, Fernando Aparecido ^[1] ; dos Santos, Diego Pereira ^[1] ; Mazali, Italo Odone ^[1]

Affiliation

^[1] Univ Estadual Campinas, Lab Funct Mat, Inst Chem IQ, UNICAMP, BR-13083970 Campinas, SP - Brazil

^[2] Univ Sao Paulo, Sao Carlos Inst Phys, BR-13560970 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: ACS APPLIED NANO MATERIALS; v. 3, n. 8, p. 8138-8147, AUG 28 2020.
• Web of Science Citations: 0

Abstract

We report the dynamic behavior of surface-enhancement Raman scattering (SERS) spectra using rhodamine 6G dye (R6G, 10(-8) mol( )L(-1)) adsorbed on gold nanorods (AuNRs). SERS spectra displayed a strong time-dependence intensity in wet to dry transition states. FEG-SEM images reveal a stacking of AuNRs organization that can lead to Raman signal improvements due to the formation of a 3D hot spot matrix that acts as a trap for target molecules. AuNRs nanostructured films were efficiently employed to form SERS substrates. The independent random AuNR organization in the SERS spectra exhibits a characteristic profile of intensities due to different dielectric environmental conditions. Despite the variations observed in the spectra array, a pattern was recognized by statistical analysis. Multidimensional analysis ensured the distinction of the study's requirements applied to the SERS response, exhibiting a silhouette coefficient of 0.92 with the least-squares projection technique. Changes in the SERS spectra profile from wet to dry state conditions of R6G dye solution can be interpreted as the dynamic behavior of R6G molecules correlated to distinct molecular adsorption and (or) surface distribution of the R6G molecules proving different plasmonic resonances. Simulations obtained from BEM calculation in experimental data corroborate that the SERS enhancement is strongly dependent on the nanoparticle coupling in nanoscale and the dielectric environment. (AU)

• FAPESP's process: 16/21070-5 - Vibrational spectroscopy with spatial resolution
• Grantee: Mauro Carlos Costa Ribeiro
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 13/22127-2 - Development of novel materials strategic for integrated analytical devices
• Grantee: Lauro Tatsuo Kubota
• Support Opportunities: Research Projects - Thematic Grants