Synergistic effect between Ag and Cu for the observation of huge SERS signal of photochemically prepared polypyrrole. Application to toxic volatile organic compounds sensing

Multifunctional Smart Conducting Polymers–Silver Nanocomposites-Modified Biocellulose Fibers for Innovative Food Packaging Applications

“…The mechanism of interaction has been previously demonstrated in detail with regard to how chemically and electrochemically synthesized CPs interact with VOCs. As is known, CPs are p-type semiconductors constituted of neutral and oxidized parts.…”

“…Gas detection experiments were conducted with a homemade apparatus as detailed in previous studies. , Briefly, a specific volume of an ammonia (NH 4 OH, Sigma-Aldrich) or acetone (C 3 H 6 O, Sigma-Aldrich) solution was placed in a round-bottom flask, which gives a two-phase (liquid–gas) equilibrium. The synthesized composites were compressed into small pellets of 7 mm diameter and 1 mm thickness and fixed, using a conducting glue, between two copper cables in the analysis chamber.…”

“…With the low polarity and high molecular weight of the latter compared to ammonia, it can be difficult for the gas to diffuse through the composite network, which may result in a lower sensing behavior toward this VOC. 43 The mechanism of interaction has been previously demonstrated in detail with regard to how chemically 15 and electrochemically 24 synthesized CPs interact with VOCs. As is known, CPs are p-type semiconductors constituted of neutral and oxidized parts.…”

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

“…PPy, a polymerized form of pyrrole, is a conducting polymer and a well-known SERS-active material. In the SERS spectra of PPy with silver (Ag) nanoparticles (NPs), the ring-stretching peak is red-shifted, while the CC bond peak is blue-shifted. , In contrast, both the ring-stretching and CC bond peaks in the SERS spectra of PPy on Ag electrodes are blue-shifted . Even though the same metal (Ag) was utilized for the SERS of PPy, the ring-stretching SERS peak shifted in opposite directions.…”

“…As previously mentioned, it was reported that the SERS peak of ring stretching in PPy nanomaterials shows opposite red or blue shifts depending on the kind of coordinated Ag that is present (i.e., Ag NPs or a Ag electrode). However, the SERS peak of the CC bond in the spectra of both PPy nanomaterials shows only a blue shift. − It can be assumed that bulky (electrode, film) or nanostructured (NPs) Ag materials result in the opposite SERS peak shift in PPy. To verify the opposite SERS peak shift in PPy with different Ag materials, PPy materials with both Ag NP (nanostructured Ag) and Ag dendrite film (bulky Ag) coordination were prepared as illustrated in Figure , which shows the reported tendency of SERS peak shifts in the insets.…”