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Lab 3 Light & nanotechnology

September 23, 2011. Lab 3 Light & nanotechnology. Background. Materials at the nanoscale. Background. What is nanoscience? What is considered nanoscale? What is the significance?. Fullerene (C 60 , D<5nm). Nobel Prize in Chemistry 1996

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Lab 3 Light & nanotechnology

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  1. September 23, 2011 Lab 3 Light & nanotechnology

  2. Background Materials at the nanoscale

  3. Background • What is nanoscience? • What is considered nanoscale? • What is the significance?

  4. Fullerene (C60, D<5nm) • Nobel Prize in Chemistry 1996 • Harold Kroto, Robert Curl & Richard Smalley (Rice University)

  5. Graphene • Nobel Prize in Physics 2010 • Andre Geim & Konstantin Novoselov (University of Manchester)

  6. Carbon Nanotubes (D ~ 4 nm)

  7. Quantum Dots (5 to 50 nm)

  8. Gold Nanoparticles • HeLa cells with fluorescent gold nanoparticles • (Dr. Mengxiao Yu and Dr. Jie Zheng – UT Dallas).

  9. Background Properties of light

  10. Properties of Light • Light is a wave (Electromagnetic (EM) radiation) • Waves have 3 features • Wavelength (λ) • Amplitude • Frequency (ν) • EM radiation = continuous spectrum of all wavelengths (no gaps).

  11. Electromagnetic Spectrum

  12. Equations of Light • c = λν, • c is the speed of light (m/s), • λ is the wavelength (m) , • ν is the frequency (s-1) • ∆E = hν • h is Planck’s constant (J s) • ν is the frequency (s-1) • ∆E = (hc)/λ

  13. When light hits an object… • Different wavelengths can be… • Absorbed • Transmitted (allowed to pass through) • Reflected • …depending on the wavelengths of light, object’s chemical composition, and its size.

  14. Color Wheel • Object absorbs orange = blue color observed. • No light absorbed = all are reflected or transmitted (white light). • All wavelengths are absorbed = black color observed.

  15. How to separate light • Prism • Diffraction

  16. Figure 5: Diffraction of light (pg 25) • w(sinθn)= nλ • tan(θn) = yn/L

  17. Properties of light

  18. Purpose • Measure the width of a single hair using a laser pointer and diffraction. • Synthesize Ag NPs, and investigate how color is related to particle size.

  19. Materials • Laser pointer • Measuring tape • Scotch tape • Hair • Stock solutions (Sodium citrate, silver nitrate, hydrogen peroxide, potassium bromide, sodium borohydride) • Large test tubes • Stoppers or parafilm to seal test tubes • Spectrophotometer • Cuvettes (2 to 5)

  20. Safety • Wear goggles and gloves! • AgNO3 is corrosive • NaBH4 is flammable and toxic (inhalation, absorption and ingestion) • Sodium Citrate may irritate skin, etc. • Hydrogen peroxide is corrosive and causes burns to eyes, skin etc. • Don’t play with the laser pointers!

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