Limits...
Sol-Gel Thin Films for Plasmonic Gas Sensors.

Della Gaspera E, Martucci A - Sensors (Basel) (2015)

Bottom Line: Plasmonic gas sensors are optical sensors that use localized surface plasmons or extended surface plasmons as transducing platform.Surface plasmons are very sensitive to dielectric variations of the environment or to electron exchange, and these effects have been exploited for the realization of sensitive gas sensors.In this paper, we review our research work of the last few years on the synthesis and the gas sensing properties of sol-gel based nanomaterials for plasmonic sensors.

View Article: PubMed Central - PubMed

Affiliation: CSIRO Manufacturing Flagship, Bayview Ave, Clayton, Victoria 3168, Australia. enrico.dellagaspera@csiro.au.

ABSTRACT
Plasmonic gas sensors are optical sensors that use localized surface plasmons or extended surface plasmons as transducing platform. Surface plasmons are very sensitive to dielectric variations of the environment or to electron exchange, and these effects have been exploited for the realization of sensitive gas sensors. In this paper, we review our research work of the last few years on the synthesis and the gas sensing properties of sol-gel based nanomaterials for plasmonic sensors.

No MeSH data available.


(a) Optical absorption spectra of SiO2-NiO-Au films annealed at different temperatures. The color of the spectra is representative of the actual color of the samples; (b) TEM images at different magnifications of SiO2-NiO-Au films showing the cookie-like nanostructures; (c) Optical absorption change (OAC) plot of SiO2-NiO-Au films exposed to hydrogen and CO at 300 °C showing the wavelength dependent response; (d) Time resolved tests of a SiO2-NiO-Au film at 300 °C showing selectivity for H2 even when the sensor is concurrently exposed to interfering CO (λ = 640 nm); (e) OAC plots of SiO2-NiO-Au films annealed either at 500 °C or 700 °C and then exposed to 1% CO at 300 °C a few days after being prepared and after 30 months from preparation.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4541914&req=5

sensors-15-16910-f001: (a) Optical absorption spectra of SiO2-NiO-Au films annealed at different temperatures. The color of the spectra is representative of the actual color of the samples; (b) TEM images at different magnifications of SiO2-NiO-Au films showing the cookie-like nanostructures; (c) Optical absorption change (OAC) plot of SiO2-NiO-Au films exposed to hydrogen and CO at 300 °C showing the wavelength dependent response; (d) Time resolved tests of a SiO2-NiO-Au film at 300 °C showing selectivity for H2 even when the sensor is concurrently exposed to interfering CO (λ = 640 nm); (e) OAC plots of SiO2-NiO-Au films annealed either at 500 °C or 700 °C and then exposed to 1% CO at 300 °C a few days after being prepared and after 30 months from preparation.

Mentions: Our first optical gas sensors based on localized surface plasmon resonance monitoring have been fabricated embedding NiO and Au NPs within a sol-gel SiO2 matrix. We initially developed a sol-gel protocol that enables the dispersion of functional oxide nanocrystals within a porous silica films at high concentration (up to 40%) without any aggregation or segregation phenomena that would be detrimental for the optical quality of the nanocomposites. Such films have been successfully used as optical and electrical gas sensors for the detection of carbon monoxide (CO), hydrogen (H2) and water vapors [38,39]. Building on these studies, we then modified the sol-gel recipe by adding a gold precursor and we were able to prepare SiO2-NiO-Au nanocomposites in which Au and NiO NPs are either separated or coupled according to the annealing temperature. Briefly, silicon alcoxides (tetraethoxysilane, TEOS and methyltriethoxysilane, MTES) dissolved in ethanol in the presence of water and hydrochloric acid are mixed with ethanolic solutions containing precursors for nickel (nickel chloride, NiCl2) and gold (tetrachloroauric acid, HAuCl4). A proper amino-functionalized silane is introduced to homogeneously disperse Ni2+ and Au3+ ions within the silica matrix. After depositing thin films via dip-coating, a thermal treatment (500–800 °C) is performed in order to fully condense and stabilize the silica matrix, and to nucleate NiO and Au nanoparticles. Notably, different thermal treatments cause different morphologies of the NiO-Au interface: at 500 °C physically separated, evenly dispersed Au and NiO NPs are observed, and the nanocomposite thin films show a sharp LSPR peak associated with spherical Au NPs embedded in an homogeneous matrix. When increasing the annealing temperature, a progressive red shift and shape change of the LSPR peak is observed (Figure 1a), which has been assigned to the formation of coupled Au/NiO heterostructures (named “cookie-like”) [40,41].


Sol-Gel Thin Films for Plasmonic Gas Sensors.

Della Gaspera E, Martucci A - Sensors (Basel) (2015)

(a) Optical absorption spectra of SiO2-NiO-Au films annealed at different temperatures. The color of the spectra is representative of the actual color of the samples; (b) TEM images at different magnifications of SiO2-NiO-Au films showing the cookie-like nanostructures; (c) Optical absorption change (OAC) plot of SiO2-NiO-Au films exposed to hydrogen and CO at 300 °C showing the wavelength dependent response; (d) Time resolved tests of a SiO2-NiO-Au film at 300 °C showing selectivity for H2 even when the sensor is concurrently exposed to interfering CO (λ = 640 nm); (e) OAC plots of SiO2-NiO-Au films annealed either at 500 °C or 700 °C and then exposed to 1% CO at 300 °C a few days after being prepared and after 30 months from preparation.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541914&req=5

sensors-15-16910-f001: (a) Optical absorption spectra of SiO2-NiO-Au films annealed at different temperatures. The color of the spectra is representative of the actual color of the samples; (b) TEM images at different magnifications of SiO2-NiO-Au films showing the cookie-like nanostructures; (c) Optical absorption change (OAC) plot of SiO2-NiO-Au films exposed to hydrogen and CO at 300 °C showing the wavelength dependent response; (d) Time resolved tests of a SiO2-NiO-Au film at 300 °C showing selectivity for H2 even when the sensor is concurrently exposed to interfering CO (λ = 640 nm); (e) OAC plots of SiO2-NiO-Au films annealed either at 500 °C or 700 °C and then exposed to 1% CO at 300 °C a few days after being prepared and after 30 months from preparation.
Mentions: Our first optical gas sensors based on localized surface plasmon resonance monitoring have been fabricated embedding NiO and Au NPs within a sol-gel SiO2 matrix. We initially developed a sol-gel protocol that enables the dispersion of functional oxide nanocrystals within a porous silica films at high concentration (up to 40%) without any aggregation or segregation phenomena that would be detrimental for the optical quality of the nanocomposites. Such films have been successfully used as optical and electrical gas sensors for the detection of carbon monoxide (CO), hydrogen (H2) and water vapors [38,39]. Building on these studies, we then modified the sol-gel recipe by adding a gold precursor and we were able to prepare SiO2-NiO-Au nanocomposites in which Au and NiO NPs are either separated or coupled according to the annealing temperature. Briefly, silicon alcoxides (tetraethoxysilane, TEOS and methyltriethoxysilane, MTES) dissolved in ethanol in the presence of water and hydrochloric acid are mixed with ethanolic solutions containing precursors for nickel (nickel chloride, NiCl2) and gold (tetrachloroauric acid, HAuCl4). A proper amino-functionalized silane is introduced to homogeneously disperse Ni2+ and Au3+ ions within the silica matrix. After depositing thin films via dip-coating, a thermal treatment (500–800 °C) is performed in order to fully condense and stabilize the silica matrix, and to nucleate NiO and Au nanoparticles. Notably, different thermal treatments cause different morphologies of the NiO-Au interface: at 500 °C physically separated, evenly dispersed Au and NiO NPs are observed, and the nanocomposite thin films show a sharp LSPR peak associated with spherical Au NPs embedded in an homogeneous matrix. When increasing the annealing temperature, a progressive red shift and shape change of the LSPR peak is observed (Figure 1a), which has been assigned to the formation of coupled Au/NiO heterostructures (named “cookie-like”) [40,41].

Bottom Line: Plasmonic gas sensors are optical sensors that use localized surface plasmons or extended surface plasmons as transducing platform.Surface plasmons are very sensitive to dielectric variations of the environment or to electron exchange, and these effects have been exploited for the realization of sensitive gas sensors.In this paper, we review our research work of the last few years on the synthesis and the gas sensing properties of sol-gel based nanomaterials for plasmonic sensors.

View Article: PubMed Central - PubMed

Affiliation: CSIRO Manufacturing Flagship, Bayview Ave, Clayton, Victoria 3168, Australia. enrico.dellagaspera@csiro.au.

ABSTRACT
Plasmonic gas sensors are optical sensors that use localized surface plasmons or extended surface plasmons as transducing platform. Surface plasmons are very sensitive to dielectric variations of the environment or to electron exchange, and these effects have been exploited for the realization of sensitive gas sensors. In this paper, we review our research work of the last few years on the synthesis and the gas sensing properties of sol-gel based nanomaterials for plasmonic sensors.

No MeSH data available.