Nanocomposites Based on Metal and Metal Sulfide Clusters Embedded in Polystyrene

Carotenuto, G.; Giannini, Cinzia; Siliqi, Dritan; Nicolais, L.

doi:10.3390/polym3031352

Cited by 5 publications

(3 citation statements)

References 24 publications

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“…These larger, more complex Au nanostructures had a plasmon extinction peak at ∼610 nm, which gave the solution a blue color (see inset of Figure b). This type of UV–vis extinction (Figure b) has frequently been observed in Au NP clusters . Unlike the ethanol solvent results, extinction spectra in toluene for pulsed (Figure c) and continuous irradiation exposures were very similar.…”

Section: Resultssupporting

confidence: 59%

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Controlling Au Photodeposition on Large ZnO Nanoparticles

Fernando

Shortell

Noble

et al. 2016

ACS Appl. Mater. Interfaces

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This study investigated how to control the rate of photoreduction of metastable AuCl2(-) at the solid-solution interface of large ZnO nanoparticles (NPs) (50-100 nm size). Band-gap photoexcitation of electronic charge in ZnO by 370 nm UV light yielded Au NP deposition and the formation of ZnO-Au NP hybrids. Au NP growth was observed to be nonepitaxial, and the patterns of Au photodeposition onto ZnO NPs observed by high-resolution transmission electron microscopy were consistent with reduction of AuCl2(-) at ZnO facet edges and corner sites. Au NP photodeposition was effective in the presence of labile oleylamine ligands attached to the ZnO surface; however, when a strong-binding dodecanethiol ligand coated the surface, photodeposition was quenched. Rates of interfacial electron transfer at the ZnO-solution interface were adjusted by changing the solvent, and these rates were observed to strongly depend on the solvent's permittivity (ε) and viscosity. From measurements of electron transfer from ZnO to the organic dye toluidine blue at the ZnO-solution interface, it was confirmed that low ε solvent mixtures (ε ≈ 9.5) possessed markedly higher rates of photocatalytic interfacial electron transfer (∼3.2 × 10(4) electrons·particle(-1)·s(-1)) compared to solvent mixtures with high ε (ε = 29.9, ∼1.9 × 10(4) electrons·particle(-1)·s(-1)). Dissolved oxygen content in the solvent and the exposure time of ZnO to band-gap, near-UV photoexcitation were also identified as factors that strongly affected Au photodeposition behavior. Production of Au clusters was favored under conditions that caused electron accumulation in the ZnO-Au NP hybrid. Under conditions where electron discharge was rapid (such as in low ε solvents), AuCl2(-) precursor ions photoreduced at ZnO surfaces in less than 5 s, leading to deposition of several small, isolated ∼6 nm Au NP on the ZnO host instead.

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Section: Resultssupporting

confidence: 59%

“…This type of UV−vis extinction (Figure 3b) has frequently been observed in Au NP clusters. 58 Unlike the ethanol solvent results, extinction spectra in toluene for pulsed (Figure 3c) and continuous irradiation exposures were very similar. The newly formed hybrid NPs generated a Au plasmon peak extinction maximum at ∼550 nm.…”

Section: Resultsmentioning

confidence: 74%

Controlling Au Photodeposition on Large ZnO Nanoparticles

Fernando

Shortell

Noble

et al. 2016

ACS Appl. Mater. Interfaces

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“…High transparency and high refractive index are two essential optical parameters that are highly demanded for the manufacturing of smart multi-functional optoelectronics devices [ 9 ]. Careful design of such nanocomposites could yield materials that can be employed in sophisticated sensors [ 13 , 14 ], optical crystals [ 15 ], micro-lenses for imaging and medical applications [ 16 , 17 ] and ultra-fast data transmission [ 10 ]. Polymers with high refractive indices are key candidate materials for smart-scaled multi-functional materials.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Optical, Chemical and Thermal Characterizations of PMMA-PS/CeO2 Nanoparticles Thin Film

et al. 2021

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We report the synthesis of hybrid thin films based on polymethyl methacrylate) (PMMA) and polystyrene (PS) doped with 1%, 3%, 5%, and 7% of cerium dioxide nanoparticles (CeO2 NPs). The As-prepared thin films of (PMMA-PS) incorporated with CeO2 NPs are deposited on a glass substrate. The transmittance T% (λ) and reflectance R% (λ) of PMMA-PS/CeO2 NPs thin films are measured at room temperature in the spectral range (250–700) nm. High transmittance of 87% is observed in the low-energy regions. However, transmittance decreases sharply to a vanishing value in the high-energy region. In addition, as the CeO2 NPs concentration is increased, a red shift of the absorption edge is clearly observed suggesting a considerable decrease in the band gap energy of PMMA-PS/CeO2 NPs thin film. The optical constants (n and k) and related key optical and optoelectronic parameters of PMMA-PS/Ce NPs thin films are reported and interpreted. Furthermore, Tauc and Urbach models are employed to elucidate optical behavior and calculate the band gaps of the as-synthesized nanocomposite thin films. The optical band gap energy of PMMA-PS thin film is found to be 4.03 eV. Optical band gap engineering is found to be possible upon introducing CeO2 NPs into PMMA-PS polymeric thin films as demonstrated clearly by the continuous decrease of optical band gap upon increasing CeO2 content. Fourier-transform infrared spectroscopy (FTIR) analysis is conducted to identify the major vibrational modes of the nanocomposite. The peak at 541.42 cm−1 is assigned to Ce–O and indicates the incorporation of CeO2 NPs into the copolymers matrices. There were drastic changes to the width and intensity of the vibrational bands of PMMA-PS upon addition of CeO2 NPs. To examine the chemical and thermal stability, thermogravimetric (TGA) thermograms are measured. We found that (PMMA-PVA)/CeO2 NPs nanocomposite thin films are thermally stable below 110 °C. Therefore, they could be key candidate materials for a wide range of scaled multifunctional smart optical and optoelectronic devices.

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