Lab 3 Light & nanotechnologyMaterials at the nanoscaleBackgroundFullerene (C60, D<5nm)GrapheneCarbon Nanotubes (D ~ 4 nm)Quantum Dots (5 to 50 nm)Gold NanoparticlesProperties of lightProperties of LightElectromagnetic SpectrumEquations of LightWhen light hits an object…Color WheelHow to separate lightFigure 5: Diffraction of light (pg 25)Slide 17PurposeMaterialsSafetySeptember 23, 2011BackgroundBackgroundWhat is nanoscience?What is considered nanoscale?What is the significance?Fullerene (C60, D<5nm)Nobel Prize in Chemistry 1996Harold Kroto, Robert Curl & Richard Smalley (Rice University)GrapheneNobel Prize in Physics 2010 Andre Geim & Konstantin Novoselov (University of Manchester)Carbon Nanotubes (D ~ 4 nm)Quantum Dots (5 to 50 nm)Gold NanoparticlesHeLa cells with fluorescent gold nanoparticles (Dr. Mengxiao Yu and Dr. Jie Zheng – UT Dallas).BackgroundProperties 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).Electromagnetic SpectrumEquations 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)/λWhen 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.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.How to separate lightPrismDiffractionFigure 5: Diffraction of light (pg 25)w(sinθn) = nλtan(θn) = yn/LPurpose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.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)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