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Naturally inspired SERS substrates fabricated by photocatalytically depositing silver nanoparticles on cicada wings.

Tanahashi I, Harada Y - Nanoscale Res Lett (2014)

Bottom Line: In the optical absorption spectra of the Ag/TiO2-coated wings, the absorption peak due to the localized surface plasmon resonance (LSPR) of Ag nanoparticles was observed at 440 nm.Strong Surface-enhanced Raman scattering (SERS) signals of Rhodamine 6G adsorbed on the Ag/TiO2-coated wings were clearly observed using the 514.5-nm line of an Ar(+) laser.The Ag/TiO2-coated wings can be a promising candidate for naturally inspired SERS substrates.

View Article: PubMed Central - HTML - PubMed

Affiliation: Nanomaterials and Microdevices Research Center, Osaka Institute of Technology, 5-16-1 Omiya, Asahi-ku, Osaka 535-8585, Japan.

ABSTRACT
Densely stacked Ag nanoparticles with an average diameter of 199 nm were effectively deposited on TiO2-coated cicada wings (Ag/TiO2-coated wings) from a water-ethanol solution of AgNO3 using ultraviolet light irradiation at room temperature. It was seen that the surfaces of bare cicada wings contained nanopillar array structures. In the optical absorption spectra of the Ag/TiO2-coated wings, the absorption peak due to the localized surface plasmon resonance (LSPR) of Ag nanoparticles was observed at 440 nm. Strong Surface-enhanced Raman scattering (SERS) signals of Rhodamine 6G adsorbed on the Ag/TiO2-coated wings were clearly observed using the 514.5-nm line of an Ar(+) laser. The Ag/TiO2-coated wings can be a promising candidate for naturally inspired SERS substrates.

No MeSH data available.


SEM micrographs of the (a) bare cicada wing, (b) Ag/wing, and (c) Ag/TiO2-coated wing.
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Figure 1: SEM micrographs of the (a) bare cicada wing, (b) Ag/wing, and (c) Ag/TiO2-coated wing.

Mentions: Typical SEM image of the dorsal forewing of male cicada (Cryptotympana facialis) is shown in Figure 1a. In the figure, a dense nanopillar array structure with a large area is seen. Diameters and separations of the array of nanopillars are about 130 and 30 to 130 nm, respectively. From other SEM images not shown here, the nanopillar was found to be about 300 nm in height. The morphology of the surface structures was almost the same for the dorsal and ventral surfaces and between male and female specimens. It has been suggested that these structures have an antireflection property[15]. Figure 1b,c shows SEM images of the Ag/wing and Ag/TiO2-coated wing, respectively. In Figure 1b, it is seen that a part of surface is covered with irregular-shaped Ag particles. In the photoreduction process, it seems that Ag+ ions are not uniformly reduced on the functional groups of chitin of the wings. On the other hand, densely stacked Ag nanoparticles are seen in Figure 1c. A part of the micrograph field including 150 particles was randomly selected to analyze the size distribution. The average diameter of the nanoparticles was estimated to be 199 nm with a standard deviation of 41 nm. The size of the Ag nanoparticles on TiO2-coated wings was larger than that of Ag nanoparticles (113 nm) on TiO2-coated glass slides[17]. It is thus that the densely stacked Ag nanoparticles with 199 nm in average diameter were successfully prepared on TiO2-coated three-dimensional nanopillar array structures of the cicada wings. On the other hand, in the SEM images of the Ag film not shown here, the surface was smooth and the nanoparticles and nanopillars were not seen in the images.


Naturally inspired SERS substrates fabricated by photocatalytically depositing silver nanoparticles on cicada wings.

Tanahashi I, Harada Y - Nanoscale Res Lett (2014)

SEM micrographs of the (a) bare cicada wing, (b) Ag/wing, and (c) Ag/TiO2-coated wing.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4060861&req=5

Figure 1: SEM micrographs of the (a) bare cicada wing, (b) Ag/wing, and (c) Ag/TiO2-coated wing.
Mentions: Typical SEM image of the dorsal forewing of male cicada (Cryptotympana facialis) is shown in Figure 1a. In the figure, a dense nanopillar array structure with a large area is seen. Diameters and separations of the array of nanopillars are about 130 and 30 to 130 nm, respectively. From other SEM images not shown here, the nanopillar was found to be about 300 nm in height. The morphology of the surface structures was almost the same for the dorsal and ventral surfaces and between male and female specimens. It has been suggested that these structures have an antireflection property[15]. Figure 1b,c shows SEM images of the Ag/wing and Ag/TiO2-coated wing, respectively. In Figure 1b, it is seen that a part of surface is covered with irregular-shaped Ag particles. In the photoreduction process, it seems that Ag+ ions are not uniformly reduced on the functional groups of chitin of the wings. On the other hand, densely stacked Ag nanoparticles are seen in Figure 1c. A part of the micrograph field including 150 particles was randomly selected to analyze the size distribution. The average diameter of the nanoparticles was estimated to be 199 nm with a standard deviation of 41 nm. The size of the Ag nanoparticles on TiO2-coated wings was larger than that of Ag nanoparticles (113 nm) on TiO2-coated glass slides[17]. It is thus that the densely stacked Ag nanoparticles with 199 nm in average diameter were successfully prepared on TiO2-coated three-dimensional nanopillar array structures of the cicada wings. On the other hand, in the SEM images of the Ag film not shown here, the surface was smooth and the nanoparticles and nanopillars were not seen in the images.

Bottom Line: In the optical absorption spectra of the Ag/TiO2-coated wings, the absorption peak due to the localized surface plasmon resonance (LSPR) of Ag nanoparticles was observed at 440 nm.Strong Surface-enhanced Raman scattering (SERS) signals of Rhodamine 6G adsorbed on the Ag/TiO2-coated wings were clearly observed using the 514.5-nm line of an Ar(+) laser.The Ag/TiO2-coated wings can be a promising candidate for naturally inspired SERS substrates.

View Article: PubMed Central - HTML - PubMed

Affiliation: Nanomaterials and Microdevices Research Center, Osaka Institute of Technology, 5-16-1 Omiya, Asahi-ku, Osaka 535-8585, Japan.

ABSTRACT
Densely stacked Ag nanoparticles with an average diameter of 199 nm were effectively deposited on TiO2-coated cicada wings (Ag/TiO2-coated wings) from a water-ethanol solution of AgNO3 using ultraviolet light irradiation at room temperature. It was seen that the surfaces of bare cicada wings contained nanopillar array structures. In the optical absorption spectra of the Ag/TiO2-coated wings, the absorption peak due to the localized surface plasmon resonance (LSPR) of Ag nanoparticles was observed at 440 nm. Strong Surface-enhanced Raman scattering (SERS) signals of Rhodamine 6G adsorbed on the Ag/TiO2-coated wings were clearly observed using the 514.5-nm line of an Ar(+) laser. The Ag/TiO2-coated wings can be a promising candidate for naturally inspired SERS substrates.

No MeSH data available.