Dr Sulbha Kulkarni-1

Recent Trends in

Synthesis & Characterization Of

Multifunctional Materials (RTSCTMN-09) 22nd June 2009

Nano Materials Synthesis

Sulabha Kulkarni Indian Institute of Science Education & Research, Pune

Ref. Nanotechnology : Principles and Practices By Sulabha K. Kulkarni Capital Publishing Co. 7/28, Mahaveer Street, Ansari Road Daryaganj, New Delhi -110002

Nano Materials,Characterization Techniques

Contents Introduction to Quantum Mechanics Structure and Bonding Synthesis of Nanomaterials (Physical Methods) Synthesis of Nanomaterials (Chemical Methods) Synthesis of Nanomaterials (Biological Methods) Analysis Techniques Properties of Nanomaterials Nanolithography Some Special Nanomaterials Applications Practicals Nano Materials,Characterization Techniques

Lecture I

• Which are the Nanomaterials are we looking for • Methods of Synthesis

Lecture II

• What kind of analysis is needed • Available and commonly required analysis techniques • Principles of some analysis techniques with Illustrative examples Nano Materials, Characterization Techniques

Materials with Size Dependent Properties

Properties of all materials are size dependent below ~ 100 nm! CdS Au

(M. Faraday1857)!

CdSe

Ag

Nano Materials,Synthesis & Characterization Techniques

Imaging using Quantum Dots of CdSe

Smith & Nie, Analyst 129 (2004) 672

Shape Dependence 0.5

0.25 ml AgNO3 0.3 ml AgNO3 0.5 ml AgNO3

720

780

857

527 nm

0.3

Intensity

Extinction (arb.units)

0.4

0.2

0.1 BDAC/CTAB = 0.15M/0.2M

0.0 300

400

500

600

700

Wavelength (nm)

a

50 nm

800

400

600

800

1000

Aspect ratio > 1 Wavelength (nm)

Photonic Band Gap Materials

Kulkarni et al

Wonderful Carbon

Diamond

Graphite

Fullerenes

Carbon Naotubes

Latest is Graphene!

Inspiration from the Nature

Look at the Nature Carefully Micro + Nano Structure Waxy surface Superhydrophobic !

Understanding the behaviour of a water drop on a surface

water water

Superhydrophilic surface

water hydrophilic surface

Water loving-Water spreads almost completely e.g.glass

water

water hydrophobic surface

superhydrophobic

Water hating – A water bead is formed e.g. teflon pan, lotus leaf

Different Models to explain observed wettability

Wenzel

Cassie-Baxter

Both

Roach et al. Soft Matter, 2008, 4, 224–240

Lithographyically Created Hydrophobic Surfaces (Si & SU8)

Roach et al. Soft Matter, 2008, 4, 224–240

Hydrophobicity Tuning (S. K. Kulkarni) Hydrophobic-Hydrophilic Transitions (TiO2)

0.5µ m

Magnetron Sputter Deposited Thin Films

5µ m

0.5µ m

5µ m

5µ m

5µ m

5µ m 5µ m

5µ m

Anatase Thickness : 112 nm, 250 nm, 369 nm, 500 nm

RMS Roughness : 106 nm, 138 nm, 142 nm, 193 nm

X 4 0 05 0µ m

Super-hydrophobicity, CA ~ 176o

UV Induced Hydrophobicity to Hydrophilicity Transition in TiO2 Thin Films

Feet of Lizard (Geko Effect)

Reminds you of Ghorpad used by Tanaji? Novel Robos, stick tapes etc by mimicking a lizard

Solar Cells using Nanomaterials

Metal Junction Solar Cell

Polymer Solar Cell

By P. V. Kamat

Pt Electrolyte

Quantum Dot Sensitized Solar Cell

Electronics

Sports/Toys Food/Agriculture

Photonics Spintronics Display Panels

Energy Space Vehicles Consumer Goods

Medical/Diagnostics

Which are the Nanomaterials are we looking for Size Dependent Physico-Chemical Properties range of materials with change of properties, without changing chemical composition

Large Surface to Bulk Atoms Ratio

ideal for composites, reacting systems, drug delievery, energy storage etc

Assembly

organization in biological systems occurs at nanoscale, in nanoscience non-bio materials also assembled at nanoscle

Nano Materials,Characterization Techniques

Bulk, Quantum Well, Quantum Wire and Quantum Dot

Jacak, Hawrylak, Wojs, Quantum Dots (1998)

Band Gap Engineering

CdS, ZnS, CdSe, ZnSe, PbS, ZnO, MnSb, SnO2 etc

Fluorescent Particles

ZnS (CdS):Mn, Cu, Pb, Pure Semiconductors

Pigments

Fe2O3, CoAl2O4, ZnCo2O4, etc

Core-shell Particles

SiO2@CdS, ZnS etc or Au,CdS,ZnS @SiO2 or PS

Fullerenes

C60, C70

Porous Materials

Aerogels (SiO2, RF etc), Porous Silicon, MCM-41

Spintronics

Diluted Magnetic Semiconductors &Multilayers

Self Assembly

Ge/Si (111) 7x7, In/Si (111) 7x7

Q - Well Spectroscopy

Al / Si (111) 7x7

Gallery of Engineered Materials

(nm to µ m)

Materials can be in the form of Single particles (powder) Colloids, in liquids Thin Films, Multilayers, Nanowires, Nanorods, Nanotubes, Quantum Dots, etc etc

Bulk Materials can be Metals, Semiconductors, Insulators

Nano Materials, Synthesis Techniques

Nanotechnology Approaches Top Down

Bottom Up

Some Nano-Materials Synthesized in our Laboratory SiO2@Ag/Au

CdSe

ZnO Flowers

Needles

CdS Rods AAO

Tetrapods

BiFeO3

Aerogel Au

SnO2

Belts

Fe2O3 particles

Synthesis of Nanomaterials Physical - MBE,Sputter,Laser,lithography Chemical-Sol-gel, coprecipitation Biological Hybrid-CVD,MOCVD etc

Synthesis of Nanomaterials

Complicated

Simple

Choice depends upon money and expertise available

Synthesis

Physical

Biological

Chemiclal

Colloids, sol-gel, L-B films, Inverse micelles

Mechanical

High enrgy ball milling, melt mixing

Using biomembranes, DNA, enzymes and micro organisms

Hybrid

Electrochemical, Chemical vapour deposition, Particle arresting in glass or zeolites or polymers, Micro emulsion-zeolite

Vapour deposition

Physical vapour deposition, Laser ablation, Sputter deposition, electric arc deposition, ion implantation

Nano Materials,Synthesis Techniques

Different milling machines 

Tumbler mill 





Attrition mill 

Energy depends on diameter and speed of drum Primarily used for large -scale industrial applications 

High energy small -industry scale (