Chapter7-1

Sailor uc san diego quantum dots articial atoms

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Unformatted text preview: m Chem 6A Michael J. Sailor, UC San Diego Summary: The Particle in a Box elocalized particle edelocalized wave Relative Energy Confined electrons exist as standing waves, whose energies take on discrete values 20 n=4 15 10 n=3 5 confined wave 22 nh E= 2 8mL n=2 n=1 0 -0.2 0 Chem 6A Michael J. Sailor, UC San Diego 0.2 0.4 x 0.6 L 0.8 1 1.2 63 Quantum dots: Artificial atoms R = radius of the nanoparticle Chem 6A Michael J. Sailor, UC San Diego aspirin Quantum dots: Artificial atoms O O O CH3 R = radius of the nanoparticle Chem 6A Michael J. Sailor, UC San Diego aspirin OH “Artificial atoms” made from CdSe in solution Felice Frankel Michael J. Sailor, UC San Diego Bawendi Chem 6A Michael J. Sailor, UC San Diego research group, MIT “Artificial atoms” made from CdSe in solution 2 nm 2.5 nm 3 nm 4 nm 5 nm 6 nm Felice Frankel Michael J. Sailor, UC San Diego Bawendi Chem 6A Michael J. Sailor, UC San Diego research group, MIT “Artificial atoms” made from CdSe in solution The properties of a nanomaterial derive from its size— form determines function 2 nm 2.5 nm 3 nm 4 nm 5 nm 6 nm Felice Frankel Michael J. Sailor, UC San Diego Bawendi Chem 6A Michael J. Sailor, UC San Diego research group, MIT Absorption and fluorescence spectra of quantum dots depend on the size of the dot Photoluminescence emission spectra Absorption spectra 61 Å 34 hrs 12 hrs 80 min 33 Å 35 min 3 min 20 sec 22Å 10 sec 1.5 2.0 2.5 3.0 Energy (eV) 2.0 2.5 3.0 Energy (eV) Chem 6A Michael J. Sailor, UC San Diego 3.5 Absorption and fluorescence spectra of quantum dots depend on the size of the dot Photoluminescence emission spectra Absorption spectra 61 Å 6 nm 34 hrs 12 hrs 80 min 3 nm 33 Å 35 min 2 nm 3 min 20 sec 22Å 10 sec 1.5 2.0 2.5 3.0 Energy (eV) 2.0 2.5 3.0 Energy (eV) Chem 6A Michael J. Sailor, UC San Diego 3.5 Biological Applications of Quantum Dots Advantages: Applications: Stable Many Distinct Colors 84 microns Biological Staining Drug Discovery Genomics Mouse 3T3 fibroblasts simultaneously stained with red and green quantum dots Silicon quantum dots imaging a tumor in a mouse "Semiconductor nanocrystals as fluorescent biological labels." Bruchez, M.; Moronne, M.; Gin, P.; Weiss, S.; Alivisatos, A. P. Science 1998, 281, 2013-2016. Chem 6A Michael J. Sailor, UC San Diego Biodegradable silicon-based quantum dots Lift-off Etching in HF 210mA/cm2, 150s Free-standing film Porous Si Si substrate (P++) Ultrasonic fracture Activation H2O, 24h Filtering 200nm pores Luminescent Nanoparticles Nanoparticles Microparticles Park, J.-H. et al. Nature Mater. 2009, 8, 331-336. Chem 6A Michael J. Sailor, UC San Diego...
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