Nanomaterials and their Optical Applications - uni-jena.de · PDF fileNanomaterials and their...

[email protected] Lecture 05 http://www.iap.uni-jena.de/multiphoton

Nanomaterials and their Optical Applications Winter Semester 2012

Lecture 05

[email protected]

[email protected] Lecture 05 http://www.iap.uni-jena.de/multiphoton

Nanomaterials and their Optical Applications Winter Semester 2012

Lecture 05

[email protected]

No lecture on Monday December 17

[email protected] Lecture 05

Outline: Plasmonics 3

2. Fabrication of Plasmonics nanostructures

• Chemical synthesis

• Single nanoparticles

• Self assembly of nanoparticles

• Nanofabrication

3. Applications of plasmonics:

Field enhancement by plasmon coupling

Optical antennas

Field enhanced vibrational spectroscopy

Nano-tools for medicine

Stained glass, Notre Dame de Paris , 1250


Liquid chemical synthesis 4

Before the addition of the reducing agent, the gold is in solution in the Au+3 form. When the reducing agent is added, gold atoms are formed in the solution, and their concentration rises rapidly until the solution exceeds saturation. Particles then form in a process called nucleation. The remaining dissolved gold atoms bind to the nucleation sites and growth occurs.


Liquid chemical synthesis 5

Reduction is the gain of electrons or a decrease in oxidation state by a molecule, atom, or ion.

Turkevich method hot chlorauric acid with small amounts of sodium citrate solution The colloidal gold will form because the citrate ions act as both a reducing agent, and a capping agent.

J. Turkevich, P. C. Stevenson, J. Hillier, "A study of the nucleation and growth processes in the synthesis of colloidal gold", Discuss. Faraday. Soc. 1951, 11, 55-75


Under different reactions conditions… 6

• Temperature : 120 to 190, transition between regular

and irregular shapes

• Molar ratio between the materials

• Surfactants: organic compounds that are amphiphilic,

meaning they contain both hydrophobic groups (their

tails) and hydrophilic groups (their heads), lower the

surface tension of a liquid, e. g. CTAB

• Precursors: chemical compound preceding another,

like the GOLD SEEDS

SCIENCE VOL 298 13 DECEMBER 2002 p. 2177


Seed-mediated growth method 7

J. Phys. Chem. C 2010, 114, 7480–7488


Seed-mediated growth method 8

J. Phys. Chem. C 2010, 114, 7480–7488


Self-assembly method 9

Possible Forces

• Covalent : sharing a pair of electrons

• Ionic: transfer of electrons

• Metallic: strong bond

• Hydrogen: simplest covalent bond

• coordination bonds

• van der Waals : electrostatic forces

• casimir, π-π

• hydrophobic

• colloidal

• capillary forces http://hyperphysics.phy-astr.gsu.edu



1790 | Analyst, 2009, 134, 1790–1801 Linking agent or linkers

1. At an interface: water-oil, and let one of the liquid evaporate

2. Molecular linkers J. Nanosci. Lett. 2012, 2: 10



2. Molecular linkers

J. Nanosci. Lett. 2012, 2: 10



2. Molecular linkers





3. Biomediated self-assembly

DNA, proteins, Viruses, Bacteria

4. Template directed self-assembly external forces that had been placed by design elements are used in forming the self-assembled structures



ACS Nano, VOL. 4 ▪ NO. 7 ▪ 3591–3605 ▪ 2010

4. Stimuli responsive self-assembly

Temperature, pH, light, solvent polarity


Nanofabrication: Direct writing method 15

SCIENCE, p. 1407 VOL 332 17 JUNE 2011

2. Electron beam lithography

direct-writing, 2D arrays

Three-Dimensional Plasmon Rulers

1. Focused ion beam milling: drill holes

Nature Photonics, 5, 83–90 (2011)

Low throughput, expensive, no large scale fabrication for industry


Nanofabrication: Templates Lithography 16

1. Optical Lithography

Diffraction limited More expensive for extreme UV



17

1. Optical lithography: Plasmonic Nanolithography

Plasmonic Nanolithography, Werayut Srituravanich,Nicholas Fang,Cheng Sun,Qi Luo, and, and Xiang Zhang, Nano Letters 2004 4 (6), 1085-1088



J. Nanotechnol. 2011, 2, 448–458

PDMS = polydimethylsiloxane Soft stamp, transparent, chip Biocompatible, Parallelism Simplicity, Flexibility



Muhannad S. Bakir, Microelectronics Research Center , Georgia Institute of Technology



Muhannad S. Bakir, Microelectronics Research Center , Georgia Institute of Technology

metal V-grooves

Plasmonic waveguides

metal V-grooves


Outline: Plasmonics 21

6. Fabrication of Plasmonics nanostructures

• Chemical synthesis

• Single nanoparticles

• Self assembly of nanoparticles

• Nanofabrication

7. Applications of plasmonics:

Field enhancement by plasmon coupling

Optical antennas

Field enhanced vibrational spectroscopy

Nano-tools for medicine

Stained glass, Notre Dame de Paris , 1250


Applications 1. Field enhancement by plasmon coupling

22

S. Kühn, U. Håkanson, L. Rogobete, and V. Sandoghdar, “Enhancement of Single-Molecule Fluorescence Using a Gold Nanoparticle as an Optical Nanoantenna,” Physical Review Letters, vol. 97, no. 1, pp. 1-4, Jul. 2006.

• Plasmon resonance = local enhancement of the electric field, increased absorption of a molecule

• Non planar field distribution matching a molecular assembly

• Fluorescence lifetime is decreased thus the molecule returns sooner to its ground state

Interaction of a gold nanoparticle with a single molecule


Applications: 2. Nanoantennas 23

Yagi-Uda antennas EM antenna = transducer between electromagnetic waves and electric currents

HF to UHF bands (about 3 MHz to 3 GHz) High gain: 10 dB

Purpose: convert the energy of free propagating radiation to localized energy, and vice versa Antenna = transducer between free radiation and localized energy



Characteristic dimensions of an antenna are of the order of the radiation wavelength Optical antennas on the order of nanometers For a cell phone: λ/100 (for a cell phone, λ ~ 30 cm, for optics 5 nm)

Antennas for light, L. Novotny, Niek van Hulst, Nature Photonics 5, 83–90(2011Z

Bow-tie antennas Yagi-Uda antennas



• all parts of the antennas are multiple or fraction of the em radiation λ

• Not at optical frequency: penetration of radiation into metals can no longer be neglected

Geometric constant Plasma wavelength

Metal not ideal (conductivity drops at the nanoscale) but carbon nanotubes or graphene

1. Photodetection and photovoltaics Increased absorption cross-section thus reduce the dimension, power consumption

2. Nanoimaging 3. Building blocks for data processing


Applications: 3. Surface enhanced Raman spectroscopy (SERS)

26

What is Raman scattering ?

Raman = inelastic scattering of a photon

Rayleigh = elastic scattering of a photon



27


The Raman effect corresponds to the absorption and subsequent emission of a photon via an intermediate quantum state of a material. The intermediate state can be either a "real", or a virtual state. The Raman interaction leads to two possible outcomes:

• the material absorbs energy and the emitted photon has a lower energy than the absorbed photon. This outcome is labeled Stokes Raman scattering. • the material loses energy and the emitted photon has a higher energy than the absorbed photon. This outcome is labeled anti-Stokes Raman scattering.

http://en.wikipedia.org/wiki/Raman_scattering



28


inelastic scattering of a photon



29

Term paper for Physics 598 OS, Shan Jiang, University of Illinois

Raman scattering Fluorescence Infrared absorption

Fluorescence : the incident light is completely absorbed and the system is transferred to an excited state from which it can go to various lower states only after a certain resonance Raman effect : can take place for any frequency of the incident lightnot a resonant effect.rom which it can go to various lower states only after a certain resonance lifetime



30

Term paper for Physics 598 OS, Shan Jiang, University of Illinois

Internal total reflection for the momentum conservation

15 orders of magnitude enhancement

From an enhanced electric field = plasmon resonance

Chemical enhancement too (factor of 200 on non

metallic substrate) !


Applications: nanotools for medicine 31

Two combined effects: 1. Optical property: plasmon resonance 2. Thermal property : remaining energy HEAT

Metal particle = point-like sources of either light or heat

Heat generated in four different colloidal gold nanoparticles of same volume and fixed intensity



1. Temperature mapping Technique to locally probe the stationary temperature Ta of the medium surrounding nano heat-sources including those formed by plasmonic nanostructures

2 March 2009 / Vol. 17, No. 5 / OPTICS EXPRESS 3291



2. Plasmonics biosensors

Engineering nanosilver as an antibacterial, biosensor and bioimaging material, Current Opinion in Chemical Engineering Volume 1, Issue 1, October 2011, Pages 3–10



2. Plasmonics biosensors

ACS Nano, 2009, 3 (5), pp 1231–1237

Binding of molecules between plasmon structures



3. Plasmon-based optical trapping

Nature Physics 3, 477 - 480 (2007)

Plasmon nano-optical tweezers, Nature Photonics, 5, 349, 2011

Towards an integrated plasmonic platform for bio-analysis

• Low fluid volumes (less waste, lower reagents costs and less required sample Faster analysis and response times due to short diffusion distances, fast heating, high surface to volume ratios, small heat capacities.

• Compactness • Massive parallelization, high-

throughput • Lower fabrication costs, • Safer platform for chemical, radioactive or biological studies because of integration of functionality, smaller fluid volumes and stored energies



4. Thermal therapy

Kennedy et al. Gold-Nanoparticle- Mediated Thermal Therapies, Small, 2010


Current issue of Nature Photonics 37


Outlook 38

Plasmonics beyond the diffraction limit, Nature Photonics, 4, 83, 2010

S. Kühn, U. Håkanson, L. Rogobete, and V. Sandoghdar, “Enhancement of Single-Molecule Fluorescence Using a Gold Nanoparticle as an Optical Nanoantenna,” Physical Review Letters, vol. 97, no. 1, pp. 1-4, Jul. 2006.

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