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Chemistry on Ultrafast and Ultrasmall Scales Trevor Smith Ken Ghiggino Paul Mulvaney School of Chemistry, University of Melbourne.

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Presentation on theme: "Chemistry on Ultrafast and Ultrasmall Scales Trevor Smith Ken Ghiggino Paul Mulvaney School of Chemistry, University of Melbourne."— Presentation transcript:

1 Chemistry on Ultrafast and Ultrasmall Scales Trevor Smith Ken Ghiggino Paul Mulvaney School of Chemistry, University of Melbourne

2 Ultrasmall - techniques l Confocal and multiphoton microscopy l Single molecule detection and emission spectroscopy l FCS, antibunching l Polymers & quantum dots l Total internal reflection fluorescence (EWIF)

3 Ultrasmall - facilities l Scanning confocal and multiphoton microscopy l Time-resolved fluorescence imaging  LaVision PicoStar  TCSPC (EI, Becker & Hickl, other) l Single molecule detection and emission spectroscopy l FCS, antibunching, single molecule spectroscopy (spectrograph/CCD) l Polymers & quantum dots l Total internal reflection fluorescence (EWIF) l Scanning near field (SNOM)

4 Ultrafast - techniques l Time-correlated single photon counting l Time-resolved fluorescence anisotropy l Flash photolysis l Pump-probe techniques l Time-resolved absorption l Fluorescence upconversion l Multi-pulse, multi-wavelength photon echoe

5 Ultrafast - facilities l Nanosecond flash photolysis (Nd:YAG/OPO) l ns gated CCD/spectrometer l Picosecond dye lasers l Femtosecond Ti:sapphire systems l oscillator/OPO system  Pulse picked/cavity dumped  MHz rep. rates, nJ pulse energies, tuneable l amplified femtosecond Ti:sapphire oscillator/OPA  <280 kHz rep. rates, µJ-10s of nJ pulse energies, tuneable

6 Facilities l Synthesis l Light emitting polymers (PPVs) l Quantum dots

7 Evanescent Waves n1n1 n2n2 n1> n2n1> n2  Standing wave Total internal reflection (if  i >  c ) Evanescent wave E=E o exp(-x/  ) Refraction (if  i <  c ) Incident Beam, E o Interface Normal ii

8 l EWIF spectroscopy l EWIF-FCS l Time-resolved EWIFS l Time-resolved EWIF anisotropy l Time-resolved EWIF microscopy

9 l Expressions for polarisations perpendicular, s, & parallel, p, to plane of incidence: l In bulk solution: l In-plane: l Out-of-plane: Polarised EWIF z x y

10 TREWIF Anisotropy 0102030405060 70 Time (ns) BULK  = 64 nm  = 76 nm  = 113 nm INCREASING DISTANCE AWAY FROM INTERFACE 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 r(t)

11 “In-plane” and “Out-of- Plane” anisotropy

12 Time-resolved EWIF microscopy l Resolution from interface ~10’s of nm


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