Aggregated gold nanoparticles rich in electromagnetic field “hotspots” for surface enhanced Raman scattering

• Published in: Talanta (Oxford) 2025-01, Vol.282, p.126948, Article 126948
• Main Authors: Zhou, Yongcong, Zhang, Jingwen, Lai, Xiaojing, Chen, Yiquan, Fu, Fengfu, Lin, Zhenyu, Dong, Yongqiang
• Format: Article
• Language: English
• Subjects: Aggregated gold nanoparticles; Localized surface plasmon resonance; Malachite green; Plasmonic hotspots; Surface enhanced Raman scattering
• ISSN: 0039-9140; 1873-3573; 1873-3573
• DOI: 10.1016/j.talanta.2024.126948

A simple method for one-step synthesis of aggregated gold nanoparticles (a-AuNPs) using single-layer carbon dots (s-CDs) as the capping agents has been proposed. The obtained a-AuNPs are mainly composed of several spherical AuNPs of 20–25 nm sized, which aggregate to form nanogaps of ∼1 nm. Furthermore, the obtained a-AuNPs produce a strong localized surface plasmon resonance (LSPR) absorption band centered at around 640 nm, which is quite close to the wavelength of the commonly used 633 nm laser in surface enhanced Raman scattering (SERS). Thus, under the irradiation of 633 nm laser, a lot of electromagnetic field “hot spots” are formed at around the nanogaps, and strong SERS activity is achieved. The obtained a-AuNPs are dropped on tin-foil wafers to fabricate SERS substrates, which show the advantages of high sensitivity, fast response, good repeatability and satisfactory stability. On the basis, a sensitive SERS sensor is developed to detect malachite green in aquaculture water, with a low detection limit of 1 × 10−9 mol/L. A simple method is developed for one-step synthesis of aggregated gold nanoparticles showing strong localized surface plasmon resonance absorption at around 640 nm, which are applied as excellent surface enhanced Raman scattering substrates. [Display omitted] •A simple method for one-step synthesis of aggregated gold nanoparticles (a-AuNPs) is proposed.•The obtained a-AuNPs produce a strong LSPR absorption at around 640 nm, and show strong SERS activity under the 633 nm laser.•The SERS substrates show the advantages of high sensitivity, good repeatability and satisfactory stability.