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Detection of formaldehyde in water: a shape-effect on the plasmonic sensing properties of the gold nanoparticles.

Nengsih S, Umar AA, Salleh MM, Oyama M - Sensors (Basel) (2012)

Bottom Line: In typical results, it was found that the plasmonic properties of gold nanostructures were very sensitive to the presence of formaldehyde in their surrounding medium by showing the change in both the plasmonic peaks position and the intensity.However, in the present study, effective plasmonic peak shift was not observed due to the intense plasmonic coupling of closely packed nanorod structures on the surface.Nevertheless, the present results at least provide a potential strategy for response enhancement via shape-effects.

View Article: PubMed Central - PubMed

Affiliation: Institute of Microengineering and Nanoelectronic (IMEN), Universiti Kebangsaan Malaysia, UKM Bangi 43600, Selangor, Malaysia. sri_nengsih85@yahoo.com

ABSTRACT
The effect of morphology on the plasmonic sensing of the presence of formaldehyde in water by gold nanostructures has been investigated. The gold nanostructures with two different morphologies, namely spherical and rod, were prepared using a seed-mediated method. In typical results, it was found that the plasmonic properties of gold nanostructures were very sensitive to the presence of formaldehyde in their surrounding medium by showing the change in both the plasmonic peaks position and the intensity. Spherical nanoparticles (GNS), for example, indicated an increase in the sensitivity when the size was increased from 25 to 35 nm and dramatically decreased when the size was further increased. An m value, the ratio between plasmonic peak shift and refractive index change, as high as 36.5 nm/RIU (refractive index unit) was obtained so far. An expanded sensing mode to FD was obtained when gold nanostructures with nanorods morphology (GNR) were used because of the presence of two plasmonic modes for response probing. However, in the present study, effective plasmonic peak shift was not observed due to the intense plasmonic coupling of closely packed nanorod structures on the surface. Nevertheless, the present results at least provide a potential strategy for response enhancement via shape-effects. High performance plasmonic sensors could be obtained if controlled arrays of nanorods can be prepared on the surface.

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(A) Dynamic response of GNS with size of ca. 35 nm under change of FD concentrations that measured at the plasmonic peak namely 552 nm; (B) Plot of average plasmonic peaks shift versus medium refractive index change.
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f6-sensors-12-10309: (A) Dynamic response of GNS with size of ca. 35 nm under change of FD concentrations that measured at the plasmonic peak namely 552 nm; (B) Plot of average plasmonic peaks shift versus medium refractive index change.

Mentions: Figure 6A shows the corresponding dynamic response of the GNS measured at the peak of the plasmonic band, namely 552 nm, under the introduction of several concentrations of FD. As can be seen from the figure, it is confirmed that the GNS exhibit excellent response linearity with the variation of FD concentration. It can also be noted here that the plasmonic response of the GNS was relatively quick with a typical response time, the time to reach the maximum change in the absorbance, of ca. 20 s. The response was found to fully recover back to the original condition when FD was removed from the vicinity of the GNS system. The recovery time was calculated to be ca. 25 s. These results reveal that the plasmonic property of the GNS is very sensitive to the FD, on account of their high-sensitivity to the change of the refractive index of the medium.


Detection of formaldehyde in water: a shape-effect on the plasmonic sensing properties of the gold nanoparticles.

Nengsih S, Umar AA, Salleh MM, Oyama M - Sensors (Basel) (2012)

(A) Dynamic response of GNS with size of ca. 35 nm under change of FD concentrations that measured at the plasmonic peak namely 552 nm; (B) Plot of average plasmonic peaks shift versus medium refractive index change.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472829&req=5

f6-sensors-12-10309: (A) Dynamic response of GNS with size of ca. 35 nm under change of FD concentrations that measured at the plasmonic peak namely 552 nm; (B) Plot of average plasmonic peaks shift versus medium refractive index change.
Mentions: Figure 6A shows the corresponding dynamic response of the GNS measured at the peak of the plasmonic band, namely 552 nm, under the introduction of several concentrations of FD. As can be seen from the figure, it is confirmed that the GNS exhibit excellent response linearity with the variation of FD concentration. It can also be noted here that the plasmonic response of the GNS was relatively quick with a typical response time, the time to reach the maximum change in the absorbance, of ca. 20 s. The response was found to fully recover back to the original condition when FD was removed from the vicinity of the GNS system. The recovery time was calculated to be ca. 25 s. These results reveal that the plasmonic property of the GNS is very sensitive to the FD, on account of their high-sensitivity to the change of the refractive index of the medium.

Bottom Line: In typical results, it was found that the plasmonic properties of gold nanostructures were very sensitive to the presence of formaldehyde in their surrounding medium by showing the change in both the plasmonic peaks position and the intensity.However, in the present study, effective plasmonic peak shift was not observed due to the intense plasmonic coupling of closely packed nanorod structures on the surface.Nevertheless, the present results at least provide a potential strategy for response enhancement via shape-effects.

View Article: PubMed Central - PubMed

Affiliation: Institute of Microengineering and Nanoelectronic (IMEN), Universiti Kebangsaan Malaysia, UKM Bangi 43600, Selangor, Malaysia. sri_nengsih85@yahoo.com

ABSTRACT
The effect of morphology on the plasmonic sensing of the presence of formaldehyde in water by gold nanostructures has been investigated. The gold nanostructures with two different morphologies, namely spherical and rod, were prepared using a seed-mediated method. In typical results, it was found that the plasmonic properties of gold nanostructures were very sensitive to the presence of formaldehyde in their surrounding medium by showing the change in both the plasmonic peaks position and the intensity. Spherical nanoparticles (GNS), for example, indicated an increase in the sensitivity when the size was increased from 25 to 35 nm and dramatically decreased when the size was further increased. An m value, the ratio between plasmonic peak shift and refractive index change, as high as 36.5 nm/RIU (refractive index unit) was obtained so far. An expanded sensing mode to FD was obtained when gold nanostructures with nanorods morphology (GNR) were used because of the presence of two plasmonic modes for response probing. However, in the present study, effective plasmonic peak shift was not observed due to the intense plasmonic coupling of closely packed nanorod structures on the surface. Nevertheless, the present results at least provide a potential strategy for response enhancement via shape-effects. High performance plasmonic sensors could be obtained if controlled arrays of nanorods can be prepared on the surface.

Show MeSH