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RESEARCH

Work In Progress

My student colleagues and I are currently working in two fairly distinct areas: inorganic glass synthesis and thin metal film optical sensors.

Recent students in  my group include (Bold indicates currently active): 

Name

Period in Group

Current Status/ Comment

Undergraduate

Serkan Kabak 2003 - present SJSU Chem major
Kristen Dale 2001- 2002 BS Chem / Scios
Boris Getman 2003 - 2005 SJSU / Microbiology

James Grambow

2002 - 2003

SJSU Photographic Sciences

Bruce Phebus

2002 - present

SJSU Chem major

Shane Kiley

2002 - 2003

SJSU Chem major

David Rauser

2000 - 2001

BS Chem; employed Alza

Edward Sambriski

2000 - 2001

BS Chem; PhD  U. Oregon

Anh Duong

1999

BS Chem;  Honeywell

Phuoung Le Doung 1999 BA Biochem; Optometry

Thomas Allan

1999

BS Physics major U. Oregon

Graduate

Weiling Hsieh 2008-present MS Chem.Candidate
Arthur Cheng 2004-present MS Chem. Candidate
Anh Duong 2003-2008 MS Chem, InterMolecular Inc.
Hsiao-Chu Lin 2005-2008 MS Chem, pursuing PhD (Tucson)
YuChun Lu 2005-2008 MS Chem, all but thesis, Taiwan ROC job search.
Nga Doan 2001-present MS Chem, DeAnza College
Wynn Ray 2001-present MS Chem, SJSU Lecturer
Mondona Zangeneh 1999-2003 MS Chem,
Mischa Plesha 1999-2002 MS Chem; Applied Materials
 

The two major areas of research in my laboratories: 1. multi-mode surface plasmon sensing and 2. lanthanide-based electroluminescent materials.

 

The first area concerns an optical phenomenon called surface plasmon resonance (SPR).  In a typical SPR experiment, a light beam is reflected off of a 500 gold film.  Under certain precisely defined conditions the reflectivity spectrum of this Au film is extremely sensitive to the presence or absence of molecular adsorbates on the gold film.  In this capacity, SPR has emerged as the premier tool for the measurement of biomolecular interactions.  If a biomolecule (probe) of interest can be tethered to the Au surface, then both kinetic and thermodynamic information for interaction with a target can be obtained.  SPR sensors respond through the extreme sensitive of the SPR effect to near surface refractive index changes (DnSURFACE).

 

We are exploring experimental and computational methods of performing SPR spectroscopy that add molecule-specific information, e.g. spectroscopic fingerprints, to the precise DnSURFACE information.  One way we have done this is by expanding the measurement from one dimension, i.e. reflectivity (R) versus wavelength (l) or angle (q), to two i.e. R(l,q).  Two-dimensional reflectivity surfaces encode far more information than one-dimensional spectra, and in favorable cases contain spectral signatures of the adsorbate. [1]  Currently we are exploring near- and mid-infrared frequency measurements in search of a set of conditions where both refractive index and spectroscopic signatures can be obtained simultaneously for target adsorbates.  Such an achievement would add tremendously to the SPR technique because it would allow both detection and identification of target analytes.

 

In the second experimental area, we seek to adapt the ideas of solid-state electrogenerated chemiluminescence to the area of lanthanide-ion based photonic devices.  The basic idea is this electroactive molecules in the solid state behave similarly to semiconductors because they transport electrons along a fixed energy level related to the oxidation (or reduction) potential of the constituent molecules.  In 1996 Karolyn Maness and I demonstrated the electrochemical equivalent of the light emitting diode.[2]  This system was based on a ruthenium polypyridine and emitted in the red.  A far more interesting system would exploit the naturally narrow bandwidths of the lanthanide ions.  Our investigations to date have involved lanthanide ions in fluoride glasses mixtures of metal fluorides that when quenched from a melt yield fluoride ion conducting glasses with excellent near IR transmission and lanthanide ion photophysics. 



[1] Surface Plasmon Spectral Fingerprinting of Adsorbed Magnesium Phthalocyanine by Angle and Wavelength Modulation Mondona Zangeneh, Nga Doan, Edward Sambriski and Roger H. Terrill*.  Accepted for Publication Applied Spectroscopy September 2003.

[2] "Solid State Diode-Like Chemiluminescence Based on Serial Frozen Concentration Gradients in Mixed Valent Poly-[Ru(vbpy)3PF6)2] films."  Karolyn M. Maness, Roger H. Terrill, Thomas J. Meyer, Royce W. Murray and R. Mark Wightman.  J. Am. Chem. Soc., 1996, 118, 10609-10616.