SERS as a probe for the charge-transfer process in a coupled semiconductor nanoparticle system TiO₂/MBA/PbS

Abstract

The TiO2/MBA/PbS bi-semiconductor system is explored as a model to study the charge transfer process with SERS for the first time.

Porous Au/γ-AlOOH Nanoflowers for Surface-Enhanced Raman Scattering Detection of Aromatic Acid Compounds

“…Surface-enhanced Raman scattering (SERS) of metallic substrates is mainly caused by the local surface plasmon resonance (LSPR) of free electrons and has been shown to be involved in the electromagnetic mechanism (EM) effect. − Recently, semiconductor-based SERS is a growing area of interest and mainly considered to be caused by the charge-transfer (CT) behavior between the substrate and the adsorbed probe molecules, which is inexpensive and exhibits excellent stability, highly tunable surfaces, and good repeatability; most importantly, selective enhancement toward specialized molecules is expected to overcome the shortcomings of traditional precious metal substrates. , The existence of a SERS substrate aims to focus on plasmonic hot spots to significantly enhance the effect by focusing on the electromagnetic field. On the other hand, the chemical enhancement mechanism (CM) caused by the presence of semiconductors is smaller than the EM effect in SERS enhancement, so composite substrates comprised of precious metals and semiconductors are a subject under intense research focus. − However, one of the most significant challenges is that the chemical enhancement derived from CT has an unsatisfactory enhancement effect on the adsorbed molecules.…”

Photoinduced Enhanced Raman Spectroscopy with Hybrid Au@WS2 Nanosheets

“…The first one is assigned to the ring breathing axial deformation mode, which is stronger than the intensities of the other bands. The second peak is the in-plane ring breathing mode . This mode indicates the existence of a certain angle ‘θ’ between the plane of the benzene ring and the surface of AuNPs according to Ma et al The strength of the in-plane modes of MBA in SERS suggests that the analyte is adsorbed on the surfaces of AuNPs through the S atom.…”

“…The second peak is the in-plane ring breathing mode. 58 This mode indicates the existence of a certain angle 'θ' between the plane of the benzene ring and the surface of AuNPs according to Ma et al 59 The strength of the in-plane modes of MBA in SERS suggests that the analyte is adsorbed on the surfaces AuNPs through the S atom. Besides, the appearance of two extra peaks, which are located at 420 and 522 cm −1 indicate the out-of-plane mode (A 1g ) of WS 2 and the ring out-of-plane bending, 59 respectively.…”

Hydroxyl Group-Abundant TiO2 Semiconductor SERS Sensor toward Polymerization Inhibitor Sensing

“…Semiconductor-based surface-enhanced Raman scattering (SERS) has recently attracted tremendous attention as a rapid, sensitive, and nondestructive approach for the detection of trace chemicals. , Compared with the traditional noble metal-based SERS effect, arising mainly from the localized surface plasma resonance effect of free electrons, , semiconductor-based SERS is considered to be mostly derived from charge transfer (CT) behavior between the SERS substrate and the adsorbed probe molecules, − which offers significant advantages in terms of selectivity, as well as low cost, high reproducibility, high stability, and rich versatility . Considering that most previous studies are concerned with the detection of fluorescent dye molecules, one of the most significant challenges in this area is bringing semiconductor-based SERS to fruition in practical usage scenarios, which is vital to improving the competitiveness of the technology.…”