carbon nano tube by ashwini manohar shrirao

8/14/2019 Carbon nano tube by ashwini manohar shrirao

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A

PRESENTATION ONCARBON NANOTUBES

By

Ashwini Shrirao


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Contents # Discovery

# Introduction# Properties# Synthesis

# Applications


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Discovery

Discovered by Sumio Iijima

Multi-walled Nanotube in 1991

Single-walled Nanotube in 1993


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Introduction

# Basic Structure

# Classification of Nanotube

1. Single-walled Nanotube2. Multi-walled Nanotube


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Basic Structure


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Types of

Nanotubes

1.Single Walled Nanotubesa. Zigzagb. Armchairc. Chiral


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Single Walled Nanotubes


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Single WalledNanotubes

How to Classify ?

Chiral Vector R =n

a1 +m

a2


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Single Walled Nanotubes

d = (n2 + m2 + nm)1/2 0.0783 nm

Chiral angle =tan-1( n/(2m + n))


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Ropes of Carbon Nanotubes

Lattice Parameter in CNT ropes = d + 0.34 nm


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ypes oNanotubes

2. Multi-walled Carbon Nanotubes


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Properties of CNT

1. Physical

2. Optical3. Electrical4. Thermal

5. Elastic


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Physical Properties

Average Diameter of SWNT 1.2-1.4 nmDistance from opposite carbon atoms (line 1) 2.83 A

Analogous Carbon atom separation (line 2) 2.456 A

Parallel carbon bond separation (line 3) 2.45 A

Carbon bond length (line4) 1.42 A

C C tight bonding overlap energy ~ 2.5 ev

Lattice constant 17 A

Density(10,10) Armchair(17,0) Zigzag

(12,6) Chiral

1.33 g/cm31.34 g/cm3

1.40 g/cm3

Interlayer Spacing(n,n) Armchair(n,0) Zigzag(2n,n) Chiral

3.38 3.413.39


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p ca roper es

Fundamental Gap:For (n, m); n-m is divisible by 3 [Metallic]

0 eVFor (n, m); n-m is not divisible by 3 [Semi-Conducting]

~ 0.5 eV

Egap =2y0acc /d


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Optical Properties


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Electrical Properties

Resistance6500

Maximum Current Density 1013

A/m2


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Thermal Properties

Thermal Conductivity ~2000

W /m-K

Phonon Mean Free Path ~ 100 nm

Relaxation Time ~ 10-11 s


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Elastic Properties

Young's Modulus (SWNT) ~ 1Tpa

Young's Modulus (MWNT) 1.28Tpa

Maximum Tensile Strength(MWCT)~63 GPa


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ElectronicProperties


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Synthesis Of carbon

Nanotubes

1. Arc Method

2. Laser Ablation

3. Chemical Vapour Deposition


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1. Arc Method

--Yield up to 30%by weight

--Further purificationis required

--Both SWNT and MWNT upto length

of 50um can be produced


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2. Laser Ablation

--Yield >70%by weight

--Produces primarilySWNT

--Further purification is required

--Most expensive method


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3. Chemical VapourDeposition


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Deposition

--Large volume of CNTs can beformed

--Plasma enhanced chemicaldeposition- synthesize vertically

aligned carbon nanotubes--Without the plasma, the resulting

nanotubes are often randomly


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Advantages

- Single-Walled Nanotubes

- Multi-Walled Nanotubes


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-Nanotubes

1. Their resistance to chemicals isimproved

2. Do not need a catalyst forgrowth

3. Do not contain magnetic

impurities


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Applications

# Field Emission# Molecular Electronics

# Fibres and Fabrics# Conductive Plastics# Catalyst Supports

# Biomedical Applications# Energy Storage

carbon nano tube by ashwini manohar shrirao

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