Exploration of Nanoparticles

Steven Hershmanunder

Dr. Chris MurrayDepartment of Chemistry

Contents

• Introduction to nanoparticles?

• How do you make large nanostructures?

• How can computers aid in research?

• Summary

Contents

• Introduction to nanoparticles?

Nanoparticles

• Particles < 100 nm

• Quantum Confinement– 1st approximation:

http://cats.about.com/od/catpictures/ig/ContainerCats/pippinbox400x533.htm

Band Theory

Bandgap for Quantum Dot

Interesting Nanoparticle properties

• Quantized energy levels

• Tunable bandgap

• Tunable Optics

• Coulomb blockade

• Other cool stuff!

Tunable bandgap

Particle-in-a-Box

Like term for Quantum Confinement

Electrostatic attraction between valance and conductance band

Tunable optics

http://content.answers.com/main/content/wp/en/thumb/6/69/395px-Fluorescence_in_various_sized_CdSe_quantum_dots.png

Coulomb blockade

• Energy to add an electron:

< kT it can’t spontaneously happen!

Single electron transistor

Capacitance of spherical particle

Other Cool Stuff!

• Multiple carrier excitation– Next generation solar cells

• Nonlinear optics– Goodbye Beer’s law– Applications

• Change light intensity• Change wavelength• Faster optical switches

Contents

• How do you make large nanostructures?

A DNA analogy

Generating a synthetic genome by whole genome assembly:   X174 bacteriophage from synthetic oligonucleotides

Oriented attachment

• Ligation for nanoparticles

R. Lee Penn and Jillian F. Banfield "Imperfect Oriented Attachment: Dislocation Generation in Defect-Free Nanocrystals" Science 281 (5379) : 969-971. (1998) (in Reports)

Contents

• How can computers aid in research?

Modeling Exotic-Shaped Nanoparticles

Quickly apply theory

WAXD

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500000

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1500000

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10 20 30 40 50 60 70 80 90 100 110 120 130

2theta

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And try to match it with experiment…

But lab is still being constructed

Thanks:

•Dr. Chris Murray

•Dr. Doug Yates

•Christine Eklund

•Roy Vagelos