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Core-Shell Nanoparticle Generation Using Laser Ablation Vanessa Coronado, Westside High School, Houston ISD Dr. Sy-Bor Wen/ Assistant Professor and YoungKyong Jo/ Ph.D. student Dept. of Mechanical Engineering. http://www.istm.cnr.it/~ponti/NJC06.html.

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istmr.it/~ponti/NJC06.html

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  1. Core-Shell Nanoparticle Generation Using Laser AblationVanessa Coronado, Westside High School, Houston ISDDr. Sy-Bor Wen/ Assistant Professor and YoungKyong Jo/ Ph.D. studentDept. of Mechanical Engineering http://www.istm.cnr.it/~ponti/NJC06.html

  2. Dr. Sy-Bor Wen, Department of Mechanical Engineering • Ph.D. in Mechanical Engineering @ University of California at Berkeley, CA • M.S. and B.S. in Mechanical Engineering @ National Taiwan University, Taipei, Taiwan • Working on using lasers to ablate germanium and copper and condense them together to form a nanoparticle core-shell material that has superior optical and electromagnetic properties.

  3. Ablation:\a-’blā-shən\ • Using a laser to vaporize material.

  4. What is nano? • Very small! • 1nm, is a nanometer = 10-9m. • Essentially, a billionth. • It takes up to 150,000 nanoparticles to be as wide as a human hair.

  5. Lasers being used • Excimer laser – class IV laser (short for 'excited dimer‘) 193 nm = UV light • Nd: YAG laser – class IV laser (neodymium-doped yttrium aluminum garnet) 532 nm= green light en.wikipedia.org/wiki/Nd-YAG_laser

  6. The laser light is fed through a series of mirrors and lenses to a closed chamber that has the samples of copper and germanium inside.

  7. Two pulsed laser ablation *Sample alignment • Courtesy of YoungKyong Jo Nd:YAG laser *Copper Fiber 0.25 mm Excimer Laser *Optical Fiber *different materials used in current lab set-up.

  8. The excimer laser is triggered first to ablate the germanium and a fraction of a second later the Nd: YAG laser will be triggered to ablate the copper sample. Courtesy of YoungKyong Jo

  9. A plume of germanium is first created then the copper is ablated to create a larger second plume that will condense onto the first. • This is all captured by an ICCD camera. An ICCD camera captures light as sensitive as a single photon….much better than my camera… Courtesy of YoungKyong Jo

  10. Once the particles have condensed and formed, they deposit on the inside of the chamber onto a collection plate strategically placed inside of the chamber. This occurs over a period of time that varies up to 2 hours. http://www.canemco.com/catalog/grids/Quantifoils.htm http://www.gatan.com/resources/answers/Answer-10.php

  11. transmission electron microscope scanning electron microscopy • The particles are then taken for imaging using a SEM- scanning electron microscope and a TEM- transmission electron microscope to see if core-shell nanoparticles were created. http://www.nims.go.jp/htm21/MA/tem.jpg

  12. Possible applications of nanoparticles • Biomedical uses – cancer cell eradication that targets only malignant cells • Better catalyst • Creates stronger magnetic field for use in electronics • Makes stronger, lighter composite materials • ? ….we don’t know what else….

  13. Variables being tested • the position within the chamber that the sample is being collected from. • the gas that is within the chamber is variably argon or helium. in air in argon

  14. Variables being tested • the time that the sample deposits on the collection grid • the time between the lasers being triggered

  15. Variables being tested • the laser energy being used • the amount of gas flowing into the chamber

  16. What are we doing? • Learning about experiment • Studying procedures • Running experiments using different variables

  17. In summary…. • 2 lasers ablate germanium and copper a fraction of a second apart • Second material condenses onto first to form core-shell particle • Particles deposit over time and are sent to a SEM and/or a TEM • If the particle is a core-shell particle…party…. then determine the properties of it.

  18. How will this translate to the physics classroom? Not sure yet…but somewhere along the lines of…(get it…it’s a little laser joke)… • Supporting TEK 8: “The student knows the characteristics and behavior of waves.” and/or • Supporting TEK 9b: “the student is expected to explain the line spectra from different gas-discharge tubes.”

  19. What might this look like? • Using classroom grade lasers coupled with mirrors and lenses to discover properties of light and waves • Use spectrum tubes to discover the differences between colors of light and what makes them unique. http://webapps.lsa.umich.edu/physics/demolab/controls/imagedemosm.aspx?picid=600

  20. Acknowledgements • Texas A&M • National Science Foundation • E3 RET Program coordinators • Mechanical Engineering Dept • Dr Sy-Bor Wen and his team • And viewers like you

  21. Any questions?

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