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Gold for Plasmotics By Tom Heinrich. Why is gold so special ?

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Presentation on theme: "Gold for Plasmotics By Tom Heinrich. Why is gold so special ?"— Presentation transcript:

1 Gold for Plasmotics By Tom Heinrich

2 Why is gold so special ?

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4 More facts about gold metal bonding Cubic-face-centered (111) lattice constant a~0,4 nm electron-dense n~5,98 E 28 m^(-3) [Xe] 4f->14 5d->10 6s->1 mean free path lamda = 42nm

5 Which elements do you use normaly for Nanopartikels ? The biggest manufacter produces nanoparticels out of nobel / royal metals. - Gold Nanoparticles - Silver Nanoparticles - Copper nanoparticles - Platinum and Palladium nanoparticles.

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8 What makes a metal nobel ?.... are metals that are particularly resistant to corrosion. Better solution for us : nobel metal = copper, silver, gold, completely filled d-bands no contribute to the conductivity and reactivity

9 Let us have a closer look at copper, silver and gold. The 3 metals withe the most distinctive shining.

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11 How could it be that silver and gold have neary the same atomic radius ? Remember gold have 32 more protons than silver !

12 Sire pleace, the answer is : Relativistic quantum effect in chemistry

13 What is the Relativistic quantum effect ? Properties of heavy atoms s-orbital electros have nearly speed of light mass growth --> contraction of the s orbitals s-electrons shild the nuclear charge the energy levels of the other orbitals is lifted up

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15 What does this mean for us ? Valence and conductor band approaching easier to stimulate elektros from d to s aka "Interbandanregung" for gold start at 520 nm (~ 2,38 eV) nearly free electrons in 6sp orbital

16 Band-stucture of Gold

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18 Dielectric function Model of Drude-Sommerfeld electrons = findependent, point-like and effectively- free accelerate by external electric field decelerate Collisions with metal ions Г = T^( -1) with T = time between two hits --> Variancefactor --> only effectively-free electrons g

19 OK, but now seriosly why do the most of physicy use gold for thier experiments and not silver or copper ? Ask yourself with which spoon do you eat your "sunday-morning-egg" copper, silver or gold ?

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21 Problem : We were talking about Bluks ! bar.jpg

22 Solution : let´s shrink to nanopartikel Über neue Synthesewege für ultrakleine, fluoreszente Gold-Nanopartikel und deren Einbau in Materialien by Andre Schäfer

23 Effects of shrinking to nanoscale Bigger surface by a minimum of volumina -> surface-energy lifted up -> other wavelength of the surface plasmos -> other absorbation of light discrete energy levels excited electron gas -> aktive chemical Gold nanostructures: engineering their plasmonic properties for biomedical applications

24 Influence of the surface

25 Where is the use ? Yesterday Coulering "Glas" Today Medicin, marking, Tomorrow Next generation of super-computers

26 Contrast enhancement for optical imaging Spatially resolved spectra biological sample(Phantom) Hauptquelle Gold nanostructures: engineering their plasmonic properties for biomedical applications

27 Contrast enhancement for optical imaging Gold nanostructures: engineering their plasmonic properties for biomedical applications

28 All good things come to an end... And so Fin

29 My feelings about all of this.


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