Web:  Jen Research Group
Web:  STC: Materials & Devices for Information Technology Research

Web:  GEMSEC: Genetically Engineered Materials Science & Engineering Center

Web:  DURINT:  Defense University Research Initiative on Nanotechnology

Ph. D., University of Pennsylvania, Philadelphia, PA, 1984

Professional Experience

• Chair, Dept. of Materials Science & Engineering, Univ. of Washington, Seattle, WA., Sep-2007 - present

• Director, Institute for Advanced Materials & Technology,  Univ. of Washington, Seattle, WA., 2006 - present

• Acting Chair, Dept. of Materials Science & Engineering, Univ. of Washington, Seattle, WA., Sep-2005 - Sep-2007.

• Boeing-Johnson Chair Professor, Dept. of Materials Science & Engineering, Univ. of Washington, Seattle, WA., Sep-2000 - present.

• Associate Professor, Dept. of Chemistry, Northeastern Univ., Boston, MA., 1997-1999

• Vice President, Optical Materials Division, ROI Technology, 1995-1996

• Group Leader-Senior Scientist, NLO Materials, EniChem America, 1990-1994

• Project Leader-Principal Scientist, Advanced Materials Laboratory, EniChem America, 1988-1990

• Research Scientist, Specialty Polymers Department, Allied-Signal Inc., 1984-1988

Research Interests

• Organic/Materials Chemistry, Functional Polymers, Materials Characterization, and Device Fabrication. Nanotechnology.

• Nonlinear optical dendrimers, polymers and devices for ultra-high speed modulation and signal processing in telecommunication and computation.

• Conjugated polymers for light-emitting and photovoltaic devices.

• Self-assembling process to form ordered 2-D arrays or 3-D networks through block copolymers or genetically-engineered proteins.

• Bio-inspired molecular electronics and sensing.

• Two-photon absorbing materials for 3-D microfabrication, deep tissue imaging, and photodynamic therapy for tumors.

• Low dielectric constant (k) polymers for interlayer dielectrics in microelectronics.

• Polymers for low optical loss waveguides and high bandwidth signal processing in telecommunication.

Professor Alex Jen joined the faculty of the Department of Materials Science and Engineering as the Boeing-Johnson Professor in December 1999. He has amassed a considerable amount of expertise from both industrial and academic research in the areas of organic/polymer synthesis and several new types of physical phenomena in organic functional polymers. The focus of his interdisciplinary research group is on the synthesis and characterization of organic functional materials/polymers that possess novel optical, electrical, and biological properties. For the past few years, his group has concentrated on the development of new synthetic methodologies of making highly efficient, processible, and thermally stable chromophores and polymers for nonlinear optical and light-emitting applications. In addition, he is collaborating with physicists and biologists to evaluate the suitability of using these materials for two-photon absorbing studies, such as two-photon microscopy for deep tissue imaging, 3-D microfabrication for photonic crystals and optical memory, and photodynamic therapy for the treatments of cancer tumors. 

He is currently funded by several government agencies, such as the National Science Foundation (NSF), Office of Naval Research (ONR), Air Force of Scientific Research (AFOSR), Defense Advanced Research Projects Agency (DARPA), and National Institute of Science and Technology (NIST), and Washington Technology Center (WTC). In addition, he is also funded by several industrial partners, such as the Lockheed-Martin, Lightwave Microsystems, Lumera, Telephotonics, and Gemfire. 

Development of molecular structure/property relationships and electro-optic materials for second-order nonlinear optics.

Polymeric nonlinear optical materials offer exciting new opportunities in integrated nonlinear optics. In particular, electro-optic (E-O) poled polymeric materials exhibit low dispersion and low dielectric constants. E-O polymers have been modulated to 150 GHz and exhibit few fundamental limits for ultra fast modulation and switching. However, there are major challenges in the development of E-O polymers with high E-O coefficients (r33) and good alignment (a condition for macroscopic non-centrosymmetry) stability of poled polymers at the processing (> 250 °C, several minutes) and operating (> 80 °C, several years) temperatures of the electronic devices. These practical considerations have led us to investigate new E-O polymer systems based on high temperature polyquinolines. Our recent results have demonstrated both very high r33 (as high as 65 pm/V compared to 31 pm/V for commercially available LiNbO3) and good alignment stability (> 85 °C for several months) [ J. Am. Chem. Soc., 121(2), 472, (1999)]. We have also developed several novel synthetic methodologies which allow us to functionalize very active NLO chromophores onto polymer backbones using the post tricyanovinylation and the post Mitsunobo reactions [ Chem. Mater. 8(3), 607 (1996); 10(2), 471 (1998); 11, 2218 (1999); Macromolecules, 31(12), 4049 (1998)]. These methods provide us with a wide variety of chromophore selection, easy control for the loading level of the chromophores, and great flexibility for the adjustment of the polymer's electrical and mechanical properties.

The above results provide the foundation for a major step forward in developing new matrices for E-O polymers with high poling stability. We will study the decay of the poled polymers using a multiple time scale analysis that is based on a model of hierarchical/relaxation dynamics. This effort should allow for separation of short and long time behaviors, and therefore, to devise a time/temperature scaling that permits characterization of long term stability in terms of measurements over convenient laboratory time scales. We will also collaborate with Larry Dalton (U. of Washington) to apply the double-ended crosslinking approach to functionalize and process the poled polymer systems to optimize the alignment and mechanical stability. 

Development of multi-functional polymers for electroluminescent (EL) and lasing studies

Polymer light-emitting diodes (LEDs) have gained much attention since the first discovery of using poly (p-phenylene vinylene) (PPV) as an emissive material in an electroluminescence (EL) device. In principle, polymer LEDs require the injection of holes and electrons into the emitter layer. The recombination of the injected electrons and holes in the polymer layer generates singlet excitons whose radiative decay produces visible light. An optimized LED should have efficient and balanced charge injections from both electrodes, comparable charge transporting properties for both charge carrier types, and high radiative decay quantum yield. We envisioned that if we could combine an efficient electron transporting segment, an emissive unit, and a hole-transporting segment on a single polymer backbone, the resulting polymer might possess balanced charge injecting/transporting properties for both electrons and holes. Such a polymer would allow us to fabricate efficient single-layer LED devices [Chem. Mater.,10(11), 3301 (1998); 11(1), 27 (1999); 11, 1568 (1999); Acta Polymerica 50, 105 (1998)]. 

The research is directed at 1) achieving efficient and balanced charge injection and transport, 2) understanding the nature of polymer surface and polymer/metal interfaces, and 3) increasing quantum efficiency of the LED device. 

Synthesis and structure/property relationships of two-photon absorbing dyes and polymers for three-dimensional imaging and microfabrication

Two-photon absorption (TPA) can be defined as a simultaneous absorption of two photons via virtual states in a medium. The process requires high peak power which is available from pulsed lasers. Even though two-photon processes have been known for some time, materials that exhibit a two-photon absorption have yet to find widespread applications. The reason for this is that most materials have relatively low two-photon absorption cross sections, s. The discovery of organic dyes with large two-photon absorption cross sections is thus very important to open up new research areas in the photonics and materials science.

To facilitate the design and synthesis of more efficient dyes, it is very important to establish well-defined structure/property relationships of these molecules. Fundamental understanding of the effects of chirality on two-photon absorption molecules will be developed through systematically studying of their structure/property relationships and molecular spatial configuration. In addition, we will compare the effect of the three-dimensional molecular structures in effecting the two-photon absorptivity with their one-dimensional analogs.

Another great advantage in the use of two-photon excitation comes from an extremely small excitation depth in the longitudinal direction. Two-photon absorption falls off as z4 in this direction since the process depends on the square of the excitation intensity. The exceptional volumetric confinement provided by two-photon excitation also presents unique opportunities in three-dimensional microlithography or microfabrication.  Unfortunately, very little work has been done to study the structure/property relationships of two-photon absorbing dyes and to optimize their two-photon cross sections in order to enhance the efficiency of polymerization. In addition, very little information was known for the kinetics of energy transfer in the two-photon induced polymerization. Our research is directed at applying the knowledge that we will learn from the effort in part (a) to design and synthesize monomers that function as efficient two-photon absorbing dyes in generating visible photons for radical initiated polymerization or direct electron transfer initiated polymerization. Covalent incorporation of a two-photon absorbing dye in a monomer is to ensure the dye will be present in significant quantity in the polymer and will not be excluded due to phase separation. In addition, the resulting polymers will purposely contain these dyes as fluorophores to enable imaging of the cured polymers and, particularly the interface, by two-photon confocal scanning microscopy to study the residual stress or defects that were induced during the polymerization process. 

Patents: 28
Publications: 200

Selected Publications:

"High-efficiency Light-emitting Diodes using Neutral Surfactants and Aluminum Cathode", Y-H. Niu, H. Ma, Q. Xu and A. K-Y. Jen, Appl. Phys. Lett, 86 (2005).

"Solvent-dependent Assembly of Terphenyl- and Quaterphenyldithiol on Gold and Gallium Arsenide", D. Krapchetov, H. Ma, A.K-Y. Jen, D. Fischer and Y-L. Loo, Amer Chem Soc web (2005).

"Low Temperature Relaxations and Effects on Poling Efficiencies of Dendronized Nonlinear Optical Side-chain Polymers", T. Gray, R. Overney, M. Haller, J. Juo, A. Jen, Appl Phys Lett, 86(1), (2005).

"Thiol-linked Anthraquinone Anthryl Acetylene Molecule:  Synthesis, Self-assembly and Photoelectrochemical Properties", H. Ma, M. Kang, Q. Xu, K. Kim and A. Jen, Amer Chem Soc web (2005).

"A Smartly Controlled Lattice Hardening Process to Achieve Highly Effective and Thermally Stable Crosslinked Nonlinear Optical Polymers", M. Haller, J. Luo, H. Li, T. Kim, Y. Liao, H. Ma, L.R. Dalton and A.K-Y. Jen, Macromolecules, 2004, 37(3), 688.

"Synthesis and Optoelectronic Properties of Starlike Polyfluorenes with Silsequioxane", W.J. Liu, W.C. Chen, W.C. Wu, Y.H. Niu and A.K-Y. Jen, Macromolecules, 2004, 37, 2335.

"A Side-Chain Dendronized Nonlinear Optical Polymide with Large and Thermally Stable Electro-Optic Activity", J. Luo, M. Haller, H. Li, H.Z. Tang, A.K-Y. Jen, K. Jakka, C-H. Chou and C.F. Shu, Macromolecules, 2004, 37, 248.

"Polymeric Materials and Their Orientation Techniques for Second-Order Nonlinear Optics", F. Kajzar, K. S. Lee and A. K-Y. Jen, Special Issue for Polymers for Photonic Applications", Invited Review, Adv. Polym Sci., 2003, 161, 1.

"Controlled Assembly of Conducting Monomers for Molecular Electronics", H. Zareie, H. Ma, B. Reed, A. K-Y. Jen, and M. Sarikaya, Nano Lett., 2003, 3(2), 139.

"Focused Microwave-Assisted Synthesis of Highly Efficient Nonlinear Optical Chromophores and Their Performance in Electro-Optics", S. Liu, M. Haller, H. Ma, L. R. Dalton, and A. K-Y. Jen, Adv. Mater., 2003, 15(7-8), 603.

"Hyperbranched Fluorinated Aromatic Polyester from Mild One-Pot Polymerization of AB2 Hydroxy Acid Monomer", S. Kang, J. Luo, H. Ma, L. R. Dalton, and A. K-Y. Jen, Macromolecules, 2003, 36, 4355.

"Electrophosphorescence from a Conjugated Copolymer Doped with Iridium Complex: High Brightness and Improved Operational Stability", X. Gong, J. Ostrowski, G. C. Bazan, A. J. Heeger, M. S. Liu, and A. K-Y. Jen, Adv. Mater., 2003, 15(1), 45.

"Systematic Development of High Bandwidth, Low Drive Voltage Organic Electro-Optic Devices and Their Applications," L. R. Dalton, B. H. Robinson, A. K. Y. Jen, and W. H. Steier Opt. Mater., 2003, 21, 19.

"Hybrid Electro-optic Polymer/Selective Buried Sol-gel Waveguides for the Integration of Phase-Modulator at 1.55 mm", Y. Enami, N. Peyghambarian, M. Kawazu, and A. K-Y. Jen, Appl. Phys. Lett., 2003, 82(4), 490.

"A Novel Oxadiazole-Containing Polyfluorene with Efficient Blue Electroluminescence", F-I. Wu, D. S. Reddy, C. F. Shu, M. S. Liu, A. K-Y. Jen, Chem. Mater., 2003, 15, 269.

"Highly Efficient Blue Light-Emitting Diodes from Polyfluorene Containing Bipolar Pendent Groups", C. F. Shu, R. Dodda, F. I. Wu, M. S. Liu, and A. K-Y. Jen, Macromolecules, 2003, 36, 6698.

"High-Performance Polymer Light-Emitting Diodes Fabricated with a Novel Hole Injection Layer", X. Gong, S. Liu, A. K-Y. Jen, D. Moses, and A. Heeger, Appl. Phys. Lett., 2003, 83(1), 183.

"Bright Red-Emitting Polymeric Electrophosphorescent Device from Osmium Complex Doped as a Triplet Emitter', J-H. Kim, M. S. Liu, A. K.-Y. Jen, B. Carlson, L. R. Dalton, C-F. Shu, and R. Dodda, Appl. Phys. Lett., 2003, 83(4), 776.

"Efficient Green Light-Emitting Diodes from A Silole-Containing Copolymer", M. S. Liu, J. Luo and A. K-Y. Jen, Chem. Mater., 2003, 15, 3496.

"Highly Fluorinated Trifluorovinyl Aryl Ether Monomers and Perfluorocyclobutane (PFCB) Aromatic Ether Polymers for Optical Waveguide Applications", S. Wong, H. Ma, and A. K.-Y. Jen, R. Barto, and C. Frank, Macromolecules, 2003, 36, 8001.

"Highly Efficient and Thermally Stable Electro-optic Polymer from a Smartly Controlled Poling and Crosslinking Process", J. Luo, M. Haller, H. Li, and A. K-Y. Jen, Adv. Mater., 2003, 15(19), 1635.

"Nanostructured Functional Dendrimers and Polymers for Photonics", J. Luo, H. Ma, and A. K-Y. Jen, invited review, Comptes Rendus issue on "Dendrimers and Nanosciences, France, 2003, 8(10), 793.

"Molecular Biomimetics: Nanotechnology through Biology", M. Sarikaya, C. Tamerler, A. K-Y. Jen, K. Schulten, and F. Baneyx, An Invited Review in Nature Materials, 2003, 2, 577.

"Hyper-Rayleigh Scattering and Frequency Dependence of the Molecular Hyperpolarizability of a Strong Charge-Transfer Chromophore", C. H. Wang, Y. C. Lin, O. Y. Tai, A. K-Y. Jen, and A. M. Kelley, J. Chem. Phys., 2003, 119(12), 6237.

"Nanorheological Approach for Characterization of Electroluminescent Polymer Thin Films", T. Gray, C.  Buenviaje, R.  M. Overney, S. Jenekhe, L. Zheng, A. K-Y. Jen, Appl. Phys. Lett., 2003, 83(13), 2563.

"Polarization Insensitive Transition between Sol-gel Waveguide and Electro-optic Polymer and Intensity Modulation for All-optical Networks", Y. Enami, M. Kawaz, A. K-Y. Jen, G. Meredith, N. Peyghambarian, J. Lightwave Tech., 2003, 21(9), 2053. 

"Hybrid Electro-optic Polymer/Sol-Gel Waveguide Modulator Fabricated by All-Wet Etching Process", Y. Enami, G. Meredith, A.K-Y. Jen and N. Peyghambarian, Appl. Phys. Lett., 2003, 83(23), 4692.

Education, Honors, and Awards

• Fellow of SPIE, 2006

• Fellow AAAS, 2005

• Boeing-Johnson Endowed Chair, 2000-2005

• Member of Advisory Board, Institute of Chemistry, Academia Sinica, Taiwan, 2002-2004

• Industrial Fellow (at a rank of full Professor), 1995-1999, Northwestern University, Evanston

• Founder's Award, 1995, ROI Technology

• National Science Council's Lectureship, Taiwan, 1992

• Outstanding Achievement Award, 1989, 1994, EniChem America Inc. 

• Research Fellowship, 1981, University of Pennsylvania, (Rohm & Hass).