Research Group Alumni

Person	Year	Role / Degree	Matriculated To
Dr. Angela Rudolph	2015	Postdoctoral fellow	Analyst, US Government, Washington D.C.
Nathan Sylvain		Ph.D. Candidate
Dr. Chelsea Hess Haupt	2015	Ph.D.	Associate Director for Digital Content; McGraw Hill Education, Dubuque, IA
Dr. Erin Riley	2012	Ph.D.	Postdoctoral fellow; Biostatistics, Epidemiologic and Bioinformatic Training in Environmental Health program at UW
Dr. Eric D. Bott	2012	Ph.D.	Analyst; Net Motion Wireless, WA
Jan Rey Pioquinto	2012	B.S.
Dr. Joshua D. Patterson	2011	Ph.D.	Assistant Professor; Christopher Newport University, VA
Christopher Bingham	2011	M.S.	Lab support staff; University of Washington
Dr. Dan Sluss	2009	Ph.D.	Research Scientist; Naval Reseach Lab, Bremerton, WA
Dr. Teresa Bixby	2009	Ph.D.	Assitant Professor; Lewis University, IL
Kevin Johnson	2009	M.S.	Instructor; South Seattle Community College
Mimosa Burr	2008	M.S.	Fulbright Fellow; International Institute for Industrial Environmental Economics, Sweden
Dr. Kristin Wustholz	2007	Ph.D.	Assistant Prof; College of William and Mary, VA
Jaclyn Yetter	2007	M.S.	Bellevue Community College
Dr. Catherine Cooksey	2006	Ph.D.	NIST, Washington D.C.
Dr. Josh Bolinger	2006	Ph.D.	University of Texas at Austin
Dr. Paul Wallace	2005	Ph.D.	Nanotech Users Facility, UW
Dr. Bethany Barham	2003	Ph.D.	Navy Research Labs
Dr. Ryan McLaughlin	2002	Postdoctoral Fellow	Seattle University, WA
Dr. Sophia Hayes	2001	Ph.D.	University of Cyprus
Dr. Anthony Esposito	2001	Ph.D.	Applied Research Associates, Inc., VA
Dr. Kate Foster	2000	Ph.D.	Queens College, NY
Dr. Steve Mayer	1999	Postdoctoral Fellow	University of Portland, OR
Dr. Matthew Philpott	1999	Ph.D.	Intense, Ltd., Glasgow

Research

Molecular photophysics

A well-recognized limitation of organic-photonic materials is that they are not as robust as their inorganic counterparts. Implementation of organic materials for a variety of processes (including information processing, photovoltaics, and light-emitting devices) hinges on understanding the processes that result in material decomposition, and ultimately the control of these processes. Bulk measurements of material decomposition are hindered by the inability to distinguish between the myriad of individual molecular decomposition pathways that may be operative in a material. Developing experimental techniques that provide insight into the decay processes of individual molecules is a significant challenge. One method used to measure single-molecule photophysics is the analysis of the time-dependence of single-molecule emission. Specifically, a single molecule is subjected to continuous photoexcitation and the variation of the emission with time is measured. A common signature of single-molecule emission is intermittency or "blinking" as shown figure below. Notice that the emission is characterized by switching between emissive ("on times") and non-emissive intervals ("off times"). We are interested in identifying the nature of the the non-emissive state that potentially serves as a gateway state to decomposition, and controlling the population and depopulation kinetics of this dark state.

Typically, the observation of single-molecule blinking has been taken as evidence for molecules undergoing excursions to the triplet state. However, the blinking statistics of our systems are not consistent with this hypothesis since the observed timescales are inconsistent with the known intersystem-crossing rates. Furthermore, the rate constants we observe vary with time consistent with so-called "dispersed kinetics". Etiologies proposed for distributed kinetics include molecular rotation, conformational flexibility, spectral diffusion, reversible photo-oxidation, intermolecular electron transfer, and proton transfer. We are performing experiments on a variety of materials in an attempt to differentiate between these various mechanisms. We are studying chromophore-polymer systems and investigating the dependence of dark-state population/depopulation kinetics on temperature (relative to the glass-transition temperature of the polymer host), chromophore structure, and structure of the polymer host. The below figure presents recent results from our lab where blinking was used to measure the temperature-dependent photophysics of the chromophore violamine R dispersed in poly(vinyl alcohol). Surprisingly, the blinking statistics were found be relatively invariant for temperatures around the glass-transition temperature of the polymer host. This indicates that the local molecular environment remains relatively consistent around the glass-transition temperature although the bulk viscosity of the host is undergoing a substantial change, and illustrates the importance of probing molecular photophysics on the molecular scale.

Our group also collaborates with the Kahr Group at New York University in the investigation mixed-crystal systems where single molecules are isolated in molecular crystals. This approach allows us to investigate single-molecule photophysics in well-defined environments since the crystal is ordered and restrictive with respect to translation and rotation of guest molecules. In addition, molecular bleaching due to photo-oxidation is reduced relative to oxygen-permeable matrices, and the decrease in nonradiative relaxation caused by the restrictive environment both afford enhanced photostability. These mixed-crystal materials are the optimal system for investigating single-molecule photophysics; in particular, determining the nature of the non-emissive state, its population and depopulations kinetics, as well as the coupling of the dark state to photo-decomposition pathways. Our experimental results are compared to theory in order to elucidate the energetic and kinetic details of dark-state production and decay. Recently we have determined that the dispersed-kinetic behaviour observed for 2',7'-dichlorofluorescein isolated in postassium acid phthalate (KAP) arises from proton transfer. We are exploring this hypothesis through a variety of studies including structural variation of the chromophore and host, isotopic substitution, and direct control over dielectric fluctuations of the crystal which serve to promote proton transfer.

Selected Pubications

P. J. Whitham, A. Marchoiro, K. E. Knowles, T. B. Kilburn, P. J. Reid, and D. R. Gamelin. "Single-Particle Photoluminescence Spectra, Blinking, and Delayed Luminescence of Colloidal CuInS₂ Nanocrystals" J. Phys. Chem. C, 2016, 120, 17136-17142.

C. M. Hess, A. R. Rudolph, and P. J. Reid. "Imaging the Effects of Annealing on the Polymorphic Phases of Poly(vinylidene fluoride)" J. Phys. Chem. B, 2015, 119 (10), pp 4127-4132.

C. M. Hess, A. R. Rudolph, and P. J. Reid. "New tools for elucidating the environmental origins of single molecule photoluminescence intermittency" Chemical Physics Letters, 2015, 628, 101-107.

P. J. Whitham, K. E. Knowles, P. J. Reid, D. R. Gamelin. "Photoluminescence Blinking and Reversible Electron Trapping in Copper-Doped CdSe Nanocrystals" Nano Letters, 2015, 15(6), 4045-4051.

P. J., Reid, B. Fujimoto, D. R. Gamelin. "A Simple ZnO Nanocrystal Synthesis Illustrating Three-Dimensional Quantum Confinement." Journal of Chemical Education, 2014, 91, 280-282.

C. M. Hess, E. A. Riley, J. Palos-Chávez, and P. J. Reid. "Measuring the Spatial Distribution of Dielectric Constants in Polymers through Quasi-Single Molecule Microscopy" Journal of Physical Chemistry B, 2013, 117(23), 7106-7112.

T. Engel and P. J. Reid, Thermodynamics, Statistical Thermodynamics, and Kinetics, 3rd Edition, Prentice Hall: Upper Saddle River, NJ, 2012. ISBN:978-0321824004

T. Engel and P. J. Reid, Physical Chemistry, 3rd Edition , Prentice Hall: Upper Saddle River, NJ, 2012. ISBN:978-0321812001

E. A. Riley, C. M. Hess, and P. J. Reid."Photoluminescence Intermittency from Single Quantum Dots to Organic Molecules: Emerging Themes" International Journal of Molecular Science, 2012, 13, 10, 12487-12518.

P. J. Reid, E. A. Riley, C. M. Hess, and P. J. Whitham. "Single-molecule studies of proton transfer in guest-host materials" Proceedings of SPIE, 2012, 8459, Physical Chemistry of Interfaces and Nanomaterials XI, 84590E.

E. A. Riley, C. M. Hess, J. R. L. Pioquinto, W. Kaminsky, B. Kahr and P. J. Reid, "Proton Transfer and Photoluminescence Intermittency of Single Emitters in Dyed Crystals" Journal of Physical Chemistry B, 2012.

E. A. Riley, C. M. Hess, P. J. Whitham and P. J. Reid, "Beyond Power Laws: A New Approach for Analyzing Single Molecule Photoluminescence Intermittency" Journal of Chemical Physics, 2012, 136, 184508.

J. D. Patterson, P. J. Reid. "Time-resolved infrared absorption studies of the solvent-dependent photochemistry of ClNO" Journal of Physical Chemistry B, 2012, 116, 35, 10437-43.

J. D. Patterson, T. J. Bixby and P. J. Reid, "Excited- and Ground-State Reaction Dynamics of Nitrosyl Chloride in Solution," Proceedings of the International Conference on Raman Spectroscopy, 2010, 1267, 1, 22.

D. H. Bale, B. E. Eichinger, W. Liang, X. Li, L. R. Dalton, B. H. Robinson, and P. J. Reid, "The Dielectric Dependence of the First Molecular Hyperpolarizability for Electro-optic Chromophores." Journal of Physical Chemistry B, 2011 115, 3505-3513.

E. A. Riley, C. Bingham, E. Bott, B. Kahr, P. J. Reid, "Two Mechanisms for Fluorescence Intermittency of Single Violamine R Molecules", Physical Chemistry Chemical Physics, 2011 13, 1879-1877.

B. C. Olbricht, P. A. Sullivan, B. H. Robinson, P. J. Reid, and L. R. Dalton, "Measuring Order in Contact-Poled Organic Electrooptic Materials with Variable-Angle Polarization-Referenced Absorption Spectroscopy (VAPRAS)", Journal of Physical Chemistry B, 2011 115, 231-241.

E. Bott, E. A. Riley, B. Kahr, and P. J. Reid, "Unravelling the Dispersed Kinetics of Dichlorofluoresce in in Potassium Hydrogen Phthalate Crystals," Journal of Physical Chemisty A, 2010 114, 7331-7337.

S. J. Benight, L. E. Johnson, R. Barnes, B. C. Olbriecht, D. H. Bale, P. J. Reid, B. E. Eichinger, L. R. Dalton, P. A. Sullivan and B. H. Robinson, "Reduced Dimensionality in Organic Electro-Optic Materials," Jounal of Physical Chemistry B, 2010 114, 11949-11956.

D. L. Sluss, C. Bingham, M. Burr, E. Bott, E. Riley, and P. J. Reid, "Temperature Dependent Fluorescence Intermittency for Single Molecules of Violamine R in Poly(vinyl alcohol)," Journal of Materials Chemistry, 2009, 19, 7561-7566.

E. Bott, E. Riley, B. Kahr, and P. J. Reid, "Proton-Transfer Mechanism for Dispersed Decay Kinetics of Single Molecules Isolated in Potassium Hydrogen Phthalate", ACS Nano, 2009, 3, 2403-2411.

A. Babon, E. D. Bott, M. Brustolon, M. Fabris, B. Kahr, W. Kaminsky, P. J. Reid, S. Wong, K. L. Wustholz, and R. Zanre, "Triplet States of nonlinear Optical Chromophore DCM in Single Crystals of Potassium Hydrogen Phthalate and Their Relationship to Single Molecule Dark States", Journal of the American Chemical Society, 2009, 131, 11548-11557.

T. R. Ewy, C. M. Isborn, B. E. Eichinger, B. H. Robinson, P. J. Reid, X. M. Li, L. R. Dalton, J. A. Davies, A. Elangovan, P. A. Sullivan, B. C. Olbricht, D. H. Bale, "Rational Enhancement of Second-order Nonlinearity: Bis-(4-methoxyphenyl)-heteroaryl-amine Donor-Based Chromophores--Design, Synthesis, and Electro-Optic Activity", Journal of the American Chemical Society, 2009, 130, 10565-10575.

T. Bixby, J. Patterson, J. Bolinger, and P. J. Reid, "Femtosecond Pump-Probe Studies of Actinic-Wavelength Dependence in Aqueous Chlorine Dioxide Photochemistry", Journal of Chemical Physics, 2009, 130, 154503.

T. Bixby, J. Patterson and P. J. Reid, "Femtosecond TRIR Studies of ClNO Photochemistry in Solution: Evidence for Photoisomerization and Geminate Recombination", Journal of Physical Chemistry A, 2009, 113, 3886-3894.

T. Bullard, K. L. Wustholz, M. Robertson, J. Freudenthal, P. J. Reid and B. Kahr, "Role of Kinks in Dyeing Crystals: Confocal Luminescence Microscopy from Single Molecules to Squared Centimeters", Crystal Growth & Design, 2009, 9, 982-990.

K. A. Dendramis, P. B. Allen, P. J. Reid and D. T. Chiu, "Spectrally Tunable Uncaging of Biological Stimuli from Nanocapsules", Chemical Communications, 2008, 39, 4795-4797.

J. A. Davies, A. Elangovan, P. A. Sullivan, B. C. Olbricht, D. H. Bale, T. R. Ewy, C. M. Isborn, B. E. Eichinger, B. H. Robinson, P. J. Reid, X. Li, and L. R. Dalton, "Rational enhancement of second-order nonlinearity: Bis-(4-methoxyphenyl)hetero-aryl-amino donor-based chromophores: Design, synthesis, and electrooptic activity", Journal of the American Chemical Society, 2008, 130, 10565-10575.

Y. J. Cheng, J. D. Luo, S. Huang, X. H. Zhou, Z. W. Shi, T. D. Kim, D. H. Bale, S. Takahashi, A. Yick, B. M. Polishak, S. H. Jang, L. R. Dalgon, P. J. Reid, W. H. Steier, A. K.-Y. Jen, "Donor-Acceptor Thiolated Polyenic Chromophores Exhibiting Large Optical Nonlinearity and Excellent Photostability", Chemistry of Materials, 2008, 20, 5047-5054.

A. J. P. Akelaitis, B. C. Olbricht, P. A. Sullivan, Y. Liao, S. K. Lee, D. H. Bale, D. B. Lao, W. Kaminsky, B. E. Eichinger, D. H. Choi, P. J. Reid, and L. R. Dalton, "Synthesis and Electro-optic Properties of Amino-Phenyl-Thienyl Donor Chromophores", Optical Materials, 2008, 30, 1504-1513.

B. C. Olbricht, P. A. Sullivan, G. A. Wen, A. A. Mistry, J. A. Davies, T. R. Ewy, B. E. Eichinger, B. H. Robinson, P. J. Reid, and L. R. Dalton, "Laser-Assisted Poling of Binary Chromophore Materials", Journal of Physical Chemistry C, 2008, 112, 7983-7988.

S. R. Hammond, O. Clot, K. A. Firestone, D. Lao, D. H. Bale, M. Haller, G. D. Phelan, B. Carlson, A. K.-Y. Jen, P. J. Reid and L. R. Dalton, "Site-Isolated Electro-Optic Chromophores Based on Substituted 2,2'-Bis(3,4-propylenedioxythiophene) π-Conjugated Bridges", Chemistry of Materials, 2008, 20, 3425-3434.

K. L. Wustholz, D. R. B. Sluss, B. Kahr and P. J. Reid, "Applications of Single-Molecule Microscopy to Problems in Dyed Composite Materials", International Reviews of Physical Chemistry (invited), 2008, 27, 167-200.

K. L. Wustholz, E. D. Bott, B. Kahr, and P. J. Reid, "Memory and Spectral Diffusion in Single-Molecule Emission", Journal of Physical Chemistry C, 2008, 112, 7877-7885.

K. N. Gunnerson, C. Brooksby, O. V. Prezhdo, and P. J. Reid, “Nonequilibrium Versus Equilibrium Molecular Dynamics Studies of Solvation Dynamics After OClO Photoexcitation,” Journal of Chemical Physics, 2007 127, 164510.

D. Rezzonico, M. Jazbinsek, C. Bosshard, P. Gunter, D. H. Bale, Y. Liao, L. R. Dalton, and P. J. Reid, "Photostability Studies of π-Conjugated Chromophores with Resonant and Nonresonant Light Excitation for Long-Life Polymeric Telecommunication Devices", Journal of the Optical Society of America B, 2007, 24, 2199-2207.

K. L. Wustholz, E. D. Bott, C. M Isborn, X. Li, B. Kahr, and P. J. Reid, "Dispersive Kinetics from Single Molecules Oriented in Potassium Acid Phthalate Crystals", Journal of Physical Chemistry C, 2007, 111, 9146-9156.

P. A. Sullivan, H. Rommel, Y. Liao, B. C. Olbricht, A. J P. Akelaitis, K. A. Firestone, J.-W. Kang, J. Luo, D. H. Choi, B. E. Eichinger, P. J. Reid, A. Chen, A. K.-Y. Jen, B. H. Robinson and L. R. Dalton, "Theory-Guided Design and Synthesis of Multichromopore Dendrimers: An Analysis of the Electro-Optic Effect", Journal of the American Chemical Society, 2007, 129, 7523-7530.

Y. J. Cheng, J. D. Luo, S. Hau, D. H. Bale, T. D. Kim, Z. W. Shi, D. B. Lau, N. M. Tucker, Y. Q. Tian, L. R. Dalton, P. J. Reid and A. K.-Y. Jen, "Large Electro-optic Activity and Enhanced Thermal Stability from Diarylaminophenyl-Containing High-Beta Nonlinear Optical Chromophores", Chemistry of Materials, 2007, 19, 1154-1163.

D. R. B. Sluss, P. M. Wallace, K. D. Truong, B. H. Robinson, L. R. Dalton, and P. J. Reid, "Single-molecule confocal microscopy studies of electric-field induced orientation in chromophore-polymer composite materials", Procedings of SPIE, 2006, 6311, 6311K-1-10.

L. Dalton, B. Robinson, A. Jen, P. Reid, B. Eichinger, P. Sullivan, A. Akelaitis, D. Bale, M. Haller, J. Luo, S. Liu, Y. Liao, K. Firestone, A. Sago, N. Bhatambrekar, S. Bhattacharjee, J. Sinness, S. Hammond, N. Buker, R. Snoeberger, M. Lingwood, H. Rommel, J. Amend, S.-H. Jang, A. Chen, and W. Steier, "Optimizing Electro-Optic Activity in Chromophore/Polymer Composites and in Organic Chromophore Glasses", Proceedings of the SPIE, 2006, 5990, 5990C-1-10.

S.-H. Jang, J. Luo, N. M. Tucker, A. Le Clercq, E. Zojer, M. A. Haller, T.-D. Kim, J.-W. Kang, K. Firestone, D. Bale, D. Lau, J. B. Benedict, D. Cohen, W. Kaminsky, B. Kahr, J.-L. Bredas, P. J. Reid, L. R. Dalton and A. K.-Y. Jen, "Pyrroline Chromophores for Electro-Optics", Chemistry of Materials, 2006 18, 2982-2988.

C. C. Cooksey, K. Johnson, and P. J. Reid, "Femptosecond Pump-Probe Studies of Nitrosyl Chloride Photochemistry in Solution", Journal of Physical Chemistry A, 2006, 110, 8613-8622.

Y. Liao, S. Bhattacharjee, K. A. Firestone, B. E. Eichinger, R. Paranji, C. A. Anderson, B. H. Robinson, P. J. Reid, and L. R. Dalton, "Antiparallel-Aligned Neutral-Ground-State and Zwitterionic Chromophores as a Nonlinear Optical Material", Journal of the American Chemical Society, 2006, 128, 6847-6853.

Y. Liao, A. K. Y. Jen, B. H. Robinson, P. J. Reid, and L. R. Dalton, "Linear and Nonlinear Optical Properties of a Macrocyclic Trichromophore Bundle with Parallel-Aligned Dipole Moments", Journal of Physical Chemistry B, 2006, 110, 5453-5438.

P. M. Wallace, D. Sluss, L. R. Dalton, B. H. Robinson, and P. J. Reid, "Single-molecule microscopy studies of electric-field poling in chromophore-polymer composite materials", Journal of Physical Chemistry B, 2006, 110, 75-82.

C. C. Cooksey, K. J. Johnson, and P. J. Reid, "Time-Resolved Studies of Nitrosyl Halide Photoreaction Dynamics", in Time-Resolved Vibrational Spectroscopy XI, E. Heilweil and T. Gustafson Eds. Springer Verlag: Berlin, 2006.

J. C. Bolinger, T. J. Bixby, and P. J. Reid, "Time-Resolved Infrared Studies of the Solvent Dependent Vibrational Relaxation Dynamics of Chlorine Dioxide", in Time-Resolved Vibrational Spectroscopy XI, E. Heilweil and T. Gustafson Eds. Springer Verlag: Berlin, 2006.

L. Dalton, A. Scherer, A. Chen, A. Jen, P. Reid, B. Robinson, B. Eichinger, M. Hochberg, T. Baehr-Jones, A. Pyajt, J. Takayesu, P. Sullivan, A. Akelaitis, R. Lawson, D. Bale, M. Haller, J. Luo, S. Liu, Y. Liao, K. Firestone, S. Bhattacharjee, J. Sinness, S. Hammond, A. Srgo, N. Buker, R. Snoeberger, M. Lingwood and w. Steier, "Organic electro-Optic Glasses for WDM Applications", Proceedings of the SPIE, 2005, 6014, 6014P-1-12.

K. A. Firestone, D. B. Lao, D. M. Casmier, O. Clot, L. R. Dalton, and P. J. Reid, "Frequency-agile hyper-Rayleigh scattering studies of electro-optic chromophores", Proceedings of the SPIE, 2005, 5990, 100-109.

K. Wustholz, B. Kahr, and P. J. Reid, "Single-Molecule Orientations in Dyed Salt Crystals", Journal of Physical Chemistry B, 2005, 109, 16357-163622005.

J. C. Bolinger, T. J. Bixby, and P. J. Reid, "Time-Resolved Infrared Studies of the Solvent Dependent Vibrational Relaxation Dynamics of Chlorine Dioxide", Journal of Chemical Physics, 2005, 123, 084503.

Y. Liao, B. E. Eichinger, K. A. Firestone, M. Haller, J. Luo, W. Kaminsky, J. B. Benedict, P. J. Reid, A. K-Y Jen, L. R. Dalton, B. H. Robinson, "Systematic study of the structure-property relationship of a series of ferrocenyl nonlinear optical chromophores", Journal of the American Chemical Society, 2005, 127, 2758-2766.