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Nanoshells Under Pressure: Innovative Pressure Gauges with Gold Coating

This overview explores the fascinating world of nanoshells, particularly their use as advanced pressure gauges. Coated with a gold layer, nanoshells demonstrate unique properties under pressure, utilizing Mie theory and hybridization models to analyze their optical responses. They offer advantages over traditional ruby sensors, being smaller, tunable, and potentially more accurate. The research discusses experimental verification, calibration challenges, and applications in biosensing, cancer ablation, and plasmonics. The future of nanoshells promises significant advancements in pressure measurement technology.

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Nanoshells Under Pressure: Innovative Pressure Gauges with Gold Coating

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  1. Nanoshells underpressure Pressure gauges with a golden layer 21 July2012

  2. Overview Nanoshells DAC Mie & Hybridization theory Nanoshells (NS) under pressure Coated Nanoshells (CNS) Experiments & outview

  3. Nanoshells:Gifts in a golden wrapper • Dielectriccore & metallic shell • Tunable Au SiO2 Halas N., Optics & Photonics News, p. 26 (August 2002)

  4. Nanoshells:Gifts in a golden wrapper • Applications • Biosensing • Cancer ablation • Targetedmedication • Plasmonics • …

  5. DiamondAnvilCell (DAC) • Small pressure on large surface • DAC usesdiamonds: Table Culet

  6. DiamondAnvilCell (DAC) • Create high pressures in betweentodiamonds • In between the diamondsthere is a pressure medium: • Helium • Hydrogen • Neon • …

  7. Rubies as pressure sensor • Use the spectrum of rubiestomeasure the pressure • The R1and R2lineswill shift underpressure • Needstobecalibrated APS: http://www.aps.anl.gov/News/APS_News/Content/APS_NEWS_20080311B.php

  8. Rubies as pressure sensor • Unfortunatly the calibration is not perfect • Interference with diamond resonances Silveraet. al. Phys. stat. sol. (b) 1, 460-467 (2007)

  9. Nanoshells as pressuregauge • Use the optical response of nanoshells in stead of rubies • Why? • NS are smaller • Tunable • …

  10. Mie-theory • We use Mie-theorytocalculate the spectrum of nanoshells: Rc = 60 nm Rs = 75 nm

  11. Hybridization model • Nanoshells = cavity +sphere • Solve the Lagrangian of the electron sea which is depicted as an incompresible fluid. Prodan, et. al., Science, 302, 419 (2003)

  12. Mie vs. Hybridization • Mie solves exactly for given dielectric function, but needs further numerical manipulation. • Hybridization is not exact, but gives analytical solutions:

  13. Nanoshells underpressure • Compression of NS • Radii change: Rc(P) andRs(P) • Electrondensity changes ne(P) Vinet equation: J. Geophys. Res. 92, 9319 (1987)

  14. Nanoshells underpressure • Relative cross section:

  15. Lookinggood! • We calculate the peak shift:

  16. Pressure media • The nanoshell is not in vacuum, but inside a pressure medium. H2 SiO2 Ne He

  17. Notsogood • The shift changes direction • Andseemsto stop for He and Ne

  18. The coated nanoshell (CNS) Au SiO2 • Add an extra layer: • Will shield the influence of the medium • But leaves the compressiblity • But how thick?

  19. The coated nanoshell • A thicklayer is needed!

  20. Theoreticalpredictions • Averageresolutionfor CNS: 0,90 nm / GPa • Rubies: 0,36 nm/ GPa • Advantages: • Nanoshells canbetunedto right frequency band • Are smaller andneedlessdensity • Disadvantage: • Callibration is stillneeded

  21. Experiments Page left blank intentionally

  22. Outview • Experimentalverification • Finetuning of theory • Heating • Use as biosensor • Sensing of metallic hydrogen

  23. Nanoshells underpressure Questions? Published: N. Van den Broeck et al. JAP 110, 114318 (2011) 21 July2012

  24. Extra: waarom geen vol SiO2 bolletje? R = 200 nm R1 = 60 nm R2 = 75 nm R3 = 200 nm

  25. Extra: waarom geen Au kern en dikke SiO2 schil? R1 = 75 nm R2 = 200 nm R1 = 60 nm R2 = 75 nm R3 = 200 nm

  26. Extra: waarom geen Au kern en dikke SiO2 schil?

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