Opposite Raman Shift of Ring Stretching Dependent on the Coordinated Silver Volume in Surface-Enhanced Raman Spectroscopy of Polypyrrole

Abstract

Surface-enhanced Raman spectroscopy (SERS) can sense some molecules in a nondestructive manner. Using SERS, we investigate the shifts in the Raman peaks of polypyrrole (PPy) with two different coordinated silver (Ag) structures, Ag nanoparticles (NPs) and Ag dendrite film. The SERS spectrum of PPy with Ag NPs presents a ring-stretching peak that is red-shifted compared to the ring-stretching peak in the Raman spectrum of PPy. In contrast, the spectrum of the PPy with the Ag dendrite film exhibits a blue-shifted ring stretching peak. The various coordinated Ag nanostructures result in opposite Raman shifts of the ring stretching peak; this phenomenon has been investigated and confirmed by density functional theory (DFT) calculations of the Raman shift of the pyrrole (Py) molecule with a Ag layer (SERS of PPy with Ag NPs) and that of a charge-transferred Py molecule (SERS of PPy with Ag dendrite films). This result demonstrates that DFT calculations can be an effective tool to scrutinize Raman shifts in SERS.

A Layered Bi2Te3@PPy Cathode for Aqueous Zinc‐Ion Batteries: Mechanism and Application in Printed Flexible Batteries

“…Similarly, Raman spectroscopy showed Bi 2 Te 3 @PPy inherits the characteristic signals of both Bi 2 Te 3 and PPy (Figure 2i and Figure S7b, Supporting Information), displaying the E u 1 , E g 2 , and A 1g 2 vibrational modes of Bi 2 Te 3, [ 29 ] and the D and G bands of carbonaceous materials. [ 30,31 ] Likewise, Fourier‐transform infrared spectroscopy results also showed the Bi 2 Te 3 @PPy to contain the fingerprints of both materials, Bi 2 Te 3 and PPy (Figure S8, Supporting Information).…”

A hydrogel gripper enabling fine movement based on spatiotemporal mineralization

“…For the Raman spectrum of PPYH, the peak at 1580 cm À1 is related to the typical CQC stretching of the pyrrole ring, and the peak of 1375 cm À1 corresponds to the in-plane deformation of C-H, which further verifies the successful synthesis of PPY. 46,47 TGA was used to verify the compositions of different hydrogels. As shown in Fig.…”

Plasmonically‐Enhanced Radioluminescence Induced by Energy Transfer in Colloidal CsPbBr3 Nanocrystals via Hybridization of Silver Nanoparticles

“…[26][27][28][29] When light with a resonating wavelength irradiates metal nanoparticles (NPs; especially gold and silver NPs), the conducting electrons in the metal NPs coherently oscillate with the electric field (E-field) component of the irradiated light. This locally strengthened E-field on the surface of the metal NPs can improve efficiency of the Raman scattering , [30,31] photoluminescence (PL), [32,33] photovoltaics, [34] photosensor, [35] and photocatalysis. [36,37] Further, the RL intensity of Ag-NP-decorated X-ray scintillators can be enhanced by LSPR.…”