U N I V O E T R O S Y I T K Y Kyoto Univ. 28 - PowerPoint PPT Presentation

鈴木 基史 京都大学 U N I V O E T R O S Y I T K Y Kyoto Univ. 第 28 回無機材料に関する最近の研究成果発表会 , 2011. 1. 24, 東海大学校友会館 F KYOTO JAPAN 7 O 9 U 8 1 N D E D

Progress of our research on nanoparticles LR-WG polarizers Au, Ag nanorod arrays Au SiO 2 SiO 2 Polarizer M. Suzuki et al. , "Low-re fl ective wire-grid polarizers with absorptive interference overlayers," Nanotechnology 21 (17), 175604 (2010). M. Suzuki et al. , "Direct formation of arrays of prolate Ag nanoparticles by dynamic oblique deposition," Jpn. J. Appl. Phys. Part 2 44 (1-7), L193-L195 (2005). • Photothermal devices SERS & PC-SERS for micro- fl uid? • Polarized & M. Suzuki et al. , "In-line aligned and bottom-up Ag Wavelength selective nanorods for surface-enhanced Raman spectroscopy," Appl. Phys. Lett. 88 (20), 203121 IR emitters? (2006). Local plasmon resonator for SERS M. Suzuki et al. , "Tailoring coupling of light to local plasmons by using Ag nanorods/structured dielectric/mirror sandwiches," Journal of Nanophotonics 3 (1), 031502 (2009). http://www.nidek.co.jp/ • Nanoparticle absorber • Enhanced properties Spatiotemporal nanoheaters U N I V O E • New functions T R O S Y I T K Y Kyoto Univ. 第 28 回無機材料に関する最近の研究成果発表会 , 2011. 1. 24, 東海大学校友会館 F KYOTO JAPAN 7 O 9 U 8 1 N D E D

Au nanorod arrays for SERS In-line aligned Au nanorods prepared by dynamic oblique deposition (DOD) U N I V O E T R O S Y I T K Y Kyoto Univ. 第 28 回無機材料に関する最近の研究成果発表会 , 2011. 1. 24, 東海大学校友会館 F KYOTO JAPAN 7 O 9 U 8 1 N D E D

Near-IR Surface Enhanced Raman Scattering (SERS) • SERS: Direct and sensitive method to identify molecules • Drastic enhancement of the local fi eld due to plasma resonance in metal nanoparticles • Why NIR? • Compatible with a biological tissues’ transparency window [1] � B. Chance, "Near-Infrared Images Using Continuous, Phase-Modulated, and Pulsed → little damage to tissues Light with Quantitation of Blood and Blood Oxygenation," Annals of the New York Academy of Sciences 838 , 29-45 (1998). In order to develop the NIR SERS substrates, control of size, shape and arrangement of nanoparticles are important! U N I V O E T R O S Y I T K Y Kyoto Univ. 第 28 回無機材料に関する最近の研究成果発表会 , 2011. 1. 24, 東海大学校友会館 F KYOTO JAPAN 7 O 9 U 8 1 N D E D

Various ‘ ’ for NIR SERS substrates M. Suzuki et al., Jpn. J. Appl. Phys., 44 , L193-L195 (2005). Orendorff et al., Anal. Chem. 77, (2005) 3261. bottom up Random aggregates of nanorods Low cost Martínes et al., Phys. Rev. B 35 (1987) 9481. Obliquely deposited columns. Liao et al., Chem. Phys. Lett. 82 (1981) 355. Evaporated on lithographic template. side by side • We have succeeded in aligning the random ordered nanorods end-to-end. • Physical self-assemble technique: Dynamic oblique deposition. G. Laurent et al., Phys. Rev. B 71 (2005) 045430. EB lithographic arrays. Local fi eld can be signi fi cantly enhanced at the end of nanorod. Further enhancement is top down expected for in-line alignment. Expensive U N I V O E T R O S Y I T K Y Kyoto Univ. 第 28 回無機材料に関する最近の研究成果発表会 , 2011. 1. 24, 東海大学校友会館 F KYOTO JAPAN 7 O 9 U 8 1 N D E D

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Growth mechanism of oblique columnar structure Nucleation Self-shadowing Columnar growth • The physical origins of the columnar structure in obliquely deposited thin fi lms are the self-shadowing effects and the limited mobility of the deposited atoms. • When the vapor fl ux is obliquely incident, atoms in the growing fi lms shadow unoccupied sites from the direct sticking of incident atoms. • Owing to limited mobility, the unoccupied sites are not fi lled later. → Large islands grow selectively. • Oblique columns grow in the direction of the incident vapor beam. U N I V O E T R O S Y I T K Y Kyoto Univ. 第 28 回無機材料に関する最近の研究成果発表会 , 2011. 1. 24, 東海大学校友会館 F KYOTO JAPAN 7 O 9 U 8 1 N D E D

Preparation of shape control layer ① Preparation of SiO 2 template (Serial bideposition[SBD]) substrate Substrate: Ordinary fl at glass deposition angle ； α SiO2 Substrate is set at oblique angle and rotated by 180 ˚ with each deposition of 10 nm thick. SiO 2 α SiO2 → 79 ˚ d SiO2 → 0 — 500 nm • Columnar morphology characteristic to serial bideposition is physically self-assembled. U N I V O E T R O S Y I T K Y Kyoto Univ. 第 28 回無機材料に関する最近の研究成果発表会 , 2011. 1. 24, 東海大学校友会館 F KYOTO JAPAN 7 O 9 U 8 1 N D E D

Preparation of nanorod arrays by DOD u A , g A ② Oblique deposition of Ag (or Au) thickness of Au, Ag ； d Au, Ag deposition angle: α Ag Au, Ag α Ag α Au, Ag → 73˚ Ag d Au, Ag � → 1 � 25 nm • Au, Ag sticks only to the top of columns due to the self- shadowing and forms elongated nanoparticles so-called nanorods. U N I V O E T R O S Y I T K Y Kyoto Univ. 第 28 回無機材料に関する最近の研究成果発表会 , 2011. 1. 24, 東海大学校友会館 F KYOTO JAPAN 7 O 9 U 8 1 N D E D

Properties of Au nanorod arrays ( t Au = 10 nm, α Au = 73 ◦ ) SERS spectra of 4,4’-bpy SEM of Au nanorods. Absorbance spectra. solutions measured on Au • In-line aligned nanorods NRA. ( λ =785 nm) • Polarization dependent absorption h ( ν − ν ′ ) due to local plasma resonance. • Strong SERS. ∼ 10 7 times 4,4’-bipyridine hν 1 mM solution enhancement Ag nanordos [1] M. Suzuki, K. Nakajima, K. Kimura, T. Fukuoka, and Y. Mori, "Au Nanorod Arrays Tailored for Surface-Enhanced Raman Spectroscopy," Analytical Sciences 23 (7), 829-833 (2007). U N I V O E T R O S Y I T K Y Kyoto Univ. 第 28 回無機材料に関する最近の研究成果発表会 , 2011. 1. 24, 東海大学校友会館 F KYOTO JAPAN 7 O 9 U 8 1 N D E D

SERS 強度の濃度依存 ������� ���������������������� ������ ��� ����� ���������������� ���� �� � �� �� �� � �� �� �� � �� �� �� � �� �� �� � �� �� �� � �� �� ��������������������� �� ������� � 1014 cm -1 近傍のピーク強度の ���� � ���� � 濃度依存 ��� � ���� � �� � ���� � ���� ���� ����� ����� ����� ����� ����� ����� ��������������� �� � SERS スペクトルの変化 ( ～ 15 mW) • 1 μ mol/l までは比較的容易に 4,4’-bpy を検出できる． • レーザのスポットサイズ～ 1 μ m 2 ， ナノロッドの厚さ～ 10 nm • 1 μ m 2 × 10 nm の体積に存在する分子数 → 1 μ mol/l では 10 個以下 (6 個 ) ． 単純計算では 1 分子計測に近い高感度． U N I V O E T R O S Y I T K Y Kyoto Univ. 第 28 回無機材料に関する最近の研究成果発表会 , 2011. 1. 24, 東海大学校友会館 F KYOTO JAPAN 7 O 9 U 8 1 N D E D