nano cnr rao

“The Revolutionary Development of Nanotechnology and Vast Opportunity in the Field of Science”

Dr. G. Ramalingam, Asst. Professor, Dept. of Nanoscience and Technology, Alagappa University

SIZEA meter is about the distance from the tip of your nose to the end of your hand (1 meter = 3.28 feet).

Millimeter- One thousandth of meter.(10-3m)

Micron: a micron is a millionth of a meter (or) one thousandth of millimeter (10-6m)

Nanometer:

A nanometer is one thousandth of a micron (10–9m)(or) a billionth of a meter. ie., one billion nanometers in a meter.

What do you mean by Nano Particles ?Nano Particles are the particles of size between 1 nm to 100 nm

Nanometer - One billionth (10-9) of a meter

• The size of Hydrogen atom 0.04 nm• The size of Proteins ~ 1-20 nm• Feature size of computer chips 180 nm• Diameter of human hair ~ 10 µm

At the nanoscale, the physical, chemical, and biological properties of materials differ in fundamental and valuable ways from the properties of individual atoms and molecules or bulk matter

• 1 nm is only three to five atoms wide.

• ~40,000 times smaller than the width of an average human hair

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Higgs BOSON(God’s Particles)

Seed

TREE

Understanding Size

10 centimetre1 metre 1 centimetre 100 micrometre

10 micrometre 1 micrometre 100 nanometre 10 nanometre 1 nanometre

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Nanoparticles are of interest because of the new properties (such as chemical reactivity and optical behaviour) that they exhibit compared with larger particles of the same materials.

For example, titanium dioxide and zinc oxide become transparent at the nano scale and have found applications in sunscreens.

Nano particles have a range of potential applications:

In the short-term application such as in cosmetics, textiles and paints. In the longer term applications such as drug delivery where they could be to used to deliver drugs to a specific site in the body.

Nano particles can also be arranged into layers on surfaces, providing a large surface area and hence enhanced activity, relevant to a range of potential applications such as catalysts.

Why Nano Particles ?

SOLAR CELL Batteries

super capacitor

Nanotechnology

BIO-SENSOR

FUELL CELL

Does size really matter???• Carbon form highly conductive compounds which are 400 times stronger then steel

•Composites made from particles of nano-size ceramics or metals smaller than 100 nanometers can suddenly become much stronger than predicted by existing materials-science models.

•For example, metals with a so-called grain size of around 10 nanometers are as much as seven times harder and tougher than their ordinary counterparts with grain sizes in the micro meter range.

•The Nano particles affects many properties such as Melting pointBoiling pointBand gapOptical propertiesElectrical propertiesMagnetic properties

•Even the structure of materials changes with respect to Size

Yes, it matter much

Why nanostructures different ?

• Quantum tunneling• Quantum confinement• Surface to volume ratio

Quantum tunneling

Quantum confinement

Quantum confinement

3D 2D 1D 0D

Electrons’ Behaviour in Smaller Sizes• Energy quantization d ~ Fermi wave length of electron in a metal (F)

or exciton diameter in a semionductor • Charge quantization Charging energy (Ec) >> Thermal energy (kT)

• Ballistic d<mean free path ()

Free electron case (3D box):exp(ikr) where k =2n/L; E= ħ2k2/2m N = 2x (4kF

3/3)/(2/L)3 = VkF3/32

electron concentration N = N/VEF= (ħ2/2m) kF

2 = (ħ2/2m) (32 N) 2/3; kF = (32 N)1/3

F= 2kF= 2 (32 N)-1/3

Exciton : e-h pair bounded by attractive electrostatic interaction (H atom-like)

E

Eg

Conductionband

Valence band

Exciton levels

•Binding energy: Eex =e4/2ħ2n2

•Bohr (exciton) radius: r = n2ħ2/e21/me +1/mh

Si Ge GaAs CdSe KClEex (meV) 14.7 3.8-4.1 4.2 15 400r (nm) 4.3 11.5 12.4

E

Eg

0

Exciton bindingenergy: EexEg-Eex

n=1n =2

k

Quantum ConfinementExciton radius

R

•R<< r: Strong Confinement - 1st term (localization) dominant - Electron and hole are quantized - Energy gap ~1/R2

eg) Si<4.3 nm, Ge<11.5 nm, GaAs<12.4

•R>> r: Weak confinement - 2nd term (coulomb attraction) dominant - Exciton confinement character

L.E. Brus, J. Chem. Phys. 80, 4403(1984)

Energy for the lowest excited state relative to Egap

E(R) = h22/2R2 – 1.8e2/2R …

r

dot

Particle in a box problem

Density of State: # of states per unit energy range

N =2n2/L2 N =8n3/3L3

dN /dE = const dN /dE ~ E 1/2

k=2n/LE = ħk2/2mk =(2mE)ħN = 2xn/L= k/ = (ħ)2mE) dN /dE = ((2m)/2ħ)(E)

dN /dE ~ E

N = 2n/L

DO

SDO

SDO

S

1D 2D 3D

E = ħk2/2m= ħ/2m(kx2+ky2+kz2)

• k is discreet in confinement directions only

Size Effect: Energy Levels and DOS

A.P. Alivisatos, Science 271, 933 (1996)

3d 2d 1d 0d

EnergyD

OS

EF

Bulk Nano atom particle

Size controlled band gap tuningDiscrete Energy levels

CB

VB

Semiconductor

LUMO

HOMO

Band gap

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In the Intermediate Regime Between Bulk and Molecular Properties

Size-dependent Quantum Effect

Size Effect: Optical Spectra

A.P.Alivisatos, J. Phys. Chem. 100, 13227 (1996)

• Shift to higher energy in smaller size• Discrete structure of spectra• Increased absorption intensity

Particle size effect

As the size of the particle decreases <10 nm, surface to volume ratio increases which alters the physical properties (optical-blue

shift, energy gap increases, boiling point decreases etc.

Properties of Nano Materials

The melting point decreases dramatically as the particle size gets below 5 nm

Source: Nanoscale Materials in Chemistry, Wiley, 2001

Melting Point

Band gapThe band gap is increases with reducing the size of the particles

Surface AreaThe total surface area (or) the number of surface atom increases with reducing size of the particles

The properties of materials can be different at the Nanoscale for two main reasons: First, Nanomaterials have a relatively larger surface area when compared to the same mass of material produced in a larger form.

Nano particles can make materials more chemically reactive and affect their strength or electrical properties.

Nanoscale materials are divided into three category, 1. Zero dimension – length , breadth and heights are confined at single point.

(for example, Nano dots) 2. One dimension – It has only one parameter either length (or) breadth (or) height

( example: very thin surface coatings) 3. Two dimensions- it has only length and breadth (for example, nanowires and

nanotubes) 4. Three dimensions -it has all parameter of length, breadth and height. (for example,

Nano Particles).

Second, quantum effects can begin to dominate the behaviour of matter at the Nanoscale

3D 2D 1D 0D

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One dimensional (1D)Nano structure

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ONE DIMENSIONAL (1D) NANO

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Two dimensional (2D)Nano structure

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Three dimensional (3D)Nano structures

SYNTHESIS OF NANOMATERIALS

BASIC UNIT

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ABROAD OPPORTUNITIES

https://www.britishcouncil.in/newton-bhabha-phd-placements-programme

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Rajiv Gandhi National Fellowship for SC Candidate

OBJECTIVE : The objective of this award is to provide fellowships in the form of financial assistance to students belonging toSC to pursue higher studies leading to M.Phil and Ph.D degrees in Sciences, Humanities and Social Sciences and Engineering & Technology.

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• The Rajiv Gandhi National Fellowship (RGNF) scheme for Scheduled Tribes has been renamed as National Fellowship for Higher Education of ST Students and is formulated and funded by Ministry of Tribal Affairs. The scheme is open to candidates who belong to Scheduled Tribe and are pursuing higher studies such as regular and full time M.Phil and Ph.D degree in Sciences, Humanities, Social Sciences and Engineering & Technology. There are 750 slots for Scheduled Tribe candidates every year for all the subjects.

National Fellowship for Higher Education of ST Studentswww.ugc.ac.in

Rajiv Gandhi National Fellowship for Students with Disabilities

• SCOPE OF THE SCHEME The scheme caters total number of 200 Fellowship [Junior Research Fellows (JRF)] per year to students with disabilities. The scheme covers all universities/institutions recognized by the University Grants Commission (UGC) and Non-Universities/Institutions and is implemented by the UGC itself on the pattern of the scheme of UGC Fellowship being awarded to research students pursuing M.Phil. and Ph.D. These fellowships will be available to students with disabilities who are covered under The Persons with Disabilities (Equal Opportunities, Protection of Rights and Full Participation) Act, 1995. Thus, a person with disability who wishes to avail the benefit under the Act has to obtain a disability certificate from the medical authority notified for the purpose.

• ELIGIBILITY: i. Any student with disabilities who is already registered to M.Phil./Ph.D. degree in a University or academic institution by completing the required formalities for admission in that University or academic institution is eligible for the award of Fellowship, subject to provision of the scheme as per the advertisement of UGC.

ii. After two years, if the progress in the research works of the awardee is found satisfactory, his/her tenure will be extended for a further period of three years as Senior Research Fellowship (SRF). The research work will be assessed by a three member committee set up by the University. The committee will consist of the Supervisor, Head of the Department and one outside expert in the subject. JRF may be terminated in case the progress of the candidate is not found satisfactory by the committee. The SRF shall be sanctioned on year to year basis on the recommendation of the Supervisor of the candidate duly accepted/rejected by the Head of the Department and finally approved by the Vice-Chancellor. The total period of award of JRF and SRF shall not exceed a period of five years.

iii. The students with disabilities once considered eligible for the fellowship shall not be entitled to any other benefits from Central or State Government or any other body like UGC offering similar benefit to avoid duplication and increase coverage. Only those doing regular and full time M.Phil./Ph.D. course of a University/Research Institution shall be eligible for the fellowship. Employees of any University/College/Educational Institution/Central/State/UT Government shall be excluded from availing Fellowship, even if they are on Study Leave or EOL to pursue the M.Phil./Ph.D. course.

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Maulana Azad National Fellowship For Minority Students

• ELIGIBILITY: A candidate has to fulfill the following conditions to be eligible for award of this fellowship

(i) He/she should belong to one of the minority communities notified under Section 2 (c) of the National Commission for Minorities Act, 1992.

(ii) He/she must be registered for regular and full time M.Phil/Ph.D courses in University/Academic Institution by fulfilling conditions of admission of that University/Institution, subject to provisions of the Fellowship as per advertisement of UGC.

(iii) The minority community students once considered eligible for the fellowship shall not be entitled to benefits under any other source, Central or State Government or any other body like UGC for the same study.(iv) Prior clearance of NET/SLET examination will not be a prerequisite for award of Maulana Azad National Fellowship for minority students for M.Phil/Ph.D.(v) In order to qualify for the award of JRF/ SRF the UGC norms would be applicable at pre-M.Phil and pre-Ph.D stage, respectively, including the minimum score of 50% at post graduate level.

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National Fellowship for OBC Candidate• ELIGIBILITY: TARGET GROUP: Unemployed OBC Candidates who have passed the Post Graduate

examination in concerned subject and who desire to pursue full-time research without JRF of UGC-NET or UGC-CSIR NET. ELIGIBILITY: The candidate should belong to OBC and should have passed the Post Graduate examination and annual income of the beneficiary/parents or guardian of the beneficiary not exceeds Rs. 6.00 lakh per annum from all sources. The candidate who is already registered for M.Phil./Ph.D. will be eligible for the consideration for award of fellowship under cited scheme.The selection will be made on the basis of merit of the candidates. However, the actual payment of fellowship will be made directly to awardee through e-payment under DBT with effect from 1 st April of selection/financial year (or) from the date of Registration under M.Phil. / Ph.D. (or) from the date of joining in M.Phil / Ph.D. Programme, whichever is later.

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Post-Graduate Indira Gandhi Scholarship for Single Girl Child For PG Programs

• ELIGIBILITY: i) Any single girl child who happen to be a only child or twin daughter or fraternal daughter in the family, if one son and one daughter is available then girl child will not be considered for scholarship under the scheme.ii) The scheme is applicable to such a single girl child who has taken admission in regular, full-time 1st year Masters Degree course in any recognized university or a post graduate college. iii)This scholarship is available to PG-I year student only. iv) Admission to PG Course in distance education mode is not covered under the scheme.

Age: Girl students up to the age of 30 years at the time of admission in PG courses are eligible.

Scholarship @Rs.3100/-per month

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Post-Graduate Merit Scholarship For University Rank Holders For PG Programs

• The scholarship may be tenable for a period of two years to enable the rank holders of each university at undergraduate level to pursue their Master’s Degree. All universities/degree awarding institutions would be required to issue rank certificates to the toppers of the university in B.A., B.Sc., and B.Com. The purpose of this scheme is to attract talent for pursuing post graduate studies besides strengthening the basic subjects at Undergraduate level. The awardees, under this scheme, can pursue their Postgraduate programme in any area of specialization in any institution of higher learning in the country.Scholarship @Rs.3100/-per month www.ugc.ac.in

Post Graduate Scholarships for Professional Courses for SC/ST Candidates

• ELIGIBILITY: i) The candidate must have obtained Graduate degree in the relevant subject and obtained admission at Postgraduate level for regular full time course in any of the Professional subject in a recognized University/Institution/College.ii) Candidates pursuing post graduate course in professional subjects by correspondence or by Distance Education mode are not eligible to receive financial assistance under this scheme. iii) The upper age limit for male applicants is 45 years as on 1st July on the year of application, and 50 years in the case of female candidates. In exceptional cases,

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UGC Schemes Scholarship information

Toll free number : 1800113355

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Scholarship information

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ww w. primeministerfellowshipscheme. com

100 studentsIndustry related project

Rs.60,000/pm

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Dr.G.RAMALINGAM

Assistant Professor Dept. of Nanoscience

Alagappa University Karaikudi ramanloyola@gmail.com