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Nanoscale Architectural Control of Organic Functional Materials for Photonics

Nanoscale Architectural Control of Organic Functional Materials for Photonics. Alex K-Y. Jen Department of Materials Science & Engineering Department of Chemistry University of Washington Seattle, WA 98195-2120 ajen@u.washington.edu. Why Nanoscale Architectural Control?.

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Nanoscale Architectural Control of Organic Functional Materials for Photonics

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  1. Nanoscale Architectural Control of Organic Functional Materials for Photonics Alex K-Y. Jen Department of Materials Science & Engineering Department of Chemistry University of Washington Seattle, WA 98195-2120 ajen@u.washington.edu

  2. Why Nanoscale Architectural Control? • Electronic Isolation • Electronic Confinement • Optical Confinement • Spatially Directed Energy & Charge Transfer • Spatial Control of Chemistry • Spatially Coupling of Molecular Motion Light-harvesting Dendrimer

  3. Electro-Optic Devices: The on-ramps & interchanges of the information superhighway An electro-optic device (material) permits electrical and optical signals to talk to each other. This requires a material with a voltage-controlled index of refraction (voltage-controlled speed of light). Index of refraction = speed of light in vacuum/speed of light in material

  4. Main Approaches for Achieving Acentric Order of High Dipole Moment NLO Chromophores Sequential Self-Assembling Guest-Host Polymer Side-Chain Polymer Lattice Hardening Crosslinkable Polymer: Best candidate so far for fabricating multilayer device and achieving high temporal stability

  5. MATERIAL ISSUES: Translating Molecular Optical Nonlinearity into Macroscopic Electro-Optic Activity EO coefficient is not a simple linear function of chromophore loading. Curves exhibit a maximum. Why? Dalton & Jen et al. J. Mater. Chem., 9, 905 (1999) Marder, Kippelen, Jen, Peyghambarian, Nature, 388, 845 (1997).

  6. Comparison of Theory and Experiment: Prediction of Optimum Loading (N) and Chromophore Shape Sphere Prolate Ellipsoid Robinson and Dalton, J. Phys. Chem. A., 104, 4785 (2000)

  7. Nanoscale Tailoring of Nonlinear Optical Dendrimers and Polymers for Electro-Optics Ma & Jen, Adv. Mater., 13, 1201 (2001). Ma, Dalton, and Jen, et al., Adv. Func. Mater., 12(9), 565 (2002).

  8. Significantly Enhaced E-O Coefficient by Dendritic Chromophore Td= 245 °C, r33= 36 pm/V, 25 wt % in PQ-100 Jen et al., J. Am. Chem. Soc., 121, 473 (1999) Td= 265 °C, lmax blue-shifted by 40 nm r33= 30 pm/V, 12 wt % of dentritic chromophore in APC-polycarbonate Luo & Jen et al., Chem. Commun., 888 (2002)

  9. Fluorinated Dendrons Provide Low Optical Loss and a Modified Local Environment In solid states, the fluoro-rich dendrons dominate the micro-environments of the core chromophore • Perfluorodendron-substituted chromophore • contributed low optical loss in guest-host • APC polymer • Loss decreased significantly (0.68 dB/cm) compared to 2.5 dB/cm in the previous system 0.85 dB/cm at 1.55 mm 0.68 dB/cm at 1.3 mm Luo & Jen et al., Chem. Commun., 888 (2002)

  10. Crosslinkable PFCB Thermoset Systems • High glass-transition temperature (Tg~380 °C) • Good thermal stability (Td~470 °C) • Excellent optical transparency • (< 0.25 dB/cm at 1.55 m) • Low dielectric constant (k~2.35, 10 kHz) • Low moisture absorption • (0.021% after 24 hrs soak in water) • Low birefringence Smith and Babb et. el.,Macromolecules, 2, 852 (1996). Ma & Jen et al., Chem. Mater., 12, 1187 (2000).

  11. Dendrimer Encapsulated Chromophores Lead to Large Electro-optic Coefficient and High Thermal Stability • A Very high E-O coefficient, • r33 = 60 pm/V at 1550 nm • Excellent thermal stability • at 85 °C Jen & Dalton et al., J. Am. Chem Soc. 123, 986 (2001)

  12. Tetra-Linked and Crosslinkable NLO Dendrimer • Mw= 7,500 • Chromophore density: • 29.5 % • 4 separated-apart dye branches • 16 Crosslinakble sites Ma, Dalton, Jen et al., Adv. Func. Mater. 12, 565 (2002)

  13. Natural and Synthetic Supramolecular Systems with Cylindrical-Shape Conformation tobacco mosaic virus V. Percec et al., Nature, 391, 161 (1998)

  14. Cylindrical-Shape Conformation Derived from Dendronized Polymers Schlüter & Rabe, Angew. Chem. Int. Ed. 39, 864 (2000).

  15. Strategy to Achieve Cylindrical-Shape Conformation inNLO Synthetic Supramolecular Systems Dendritic NLO Chromophore Dendritic Crosslinker tobacco mosaic virus

  16. Dendronized Nonlinear Optical Polymers

  17. Nonlinear Optical Dendronized Polymer with Psuedo-Cylindrical-Shape Conformation

  18. Performance Comparison of Various NLO Materials Jen et al., Adv. Mater., 14(23), 1763 (2002).

  19. Performance Comparison of Various NLO Materials Jen et al., J. Am. Chem. Soc., (in preparation)

  20. Rod-Shape NLO Dendronized Polymer with Excellent E-O Activity and Alignment Thermal Stability Rigid rod polyimide as mainchain 25 wt % chromophore content Tg = 155 C, r33 = 70 pm/V, >90% of this value can be retained at85 Cfor several hundred hours Fluorinated dendron Jen & Shu et al., Macromolecules (in preparation)

  21. Lower value and higher stability, Nonlinearity-Stability Tradeoff? No Almost the same poling efficiency has been achieved. Poling efficiency parameter = r33/(C *Ep) based on the “orientated-gas model” for poled polymers High poling efficiency through the site-isolation effect can be reproduced very well in this new side-chain dendronized NLO rigid-rod polyimide with greatly improved temporal stability

  22. Nonlinearity-Stability Tradeoff in Conventional Side-Chain and Crosslinkable NLO Polymers Higher poling efficiency but lower alignment stability Electric field Poling Lattice Hardening Better alignment stability but worse poling efficiency

  23. ~ r.t to 80  C 110-150C Diels-Alder Reaction: thermally reversible, low-T addition, concerted mechanism, catalyst-free, and very cheap Bis-Maleimide Crosslinker Highly Crosslinked Network: Completely insoluble Linear Polymer: Thermoplastic, Highly soluble Excess, 130 C Crosslinker Capture Gandini A. et al., Macromolecules, 31(2), 314, (1998)

  24. Highly Crosslinked Network: very hard; easy to crack by high stress Diels-Alder Reaction Retro Diels-Alder Reaction by Heating Crack Self-Healing by Cooling Partially Disconnect the Network: flexible, processible Wudl et al, Science, 295, 1698 (2002)

  25. Reversibly Thermally Crosslinkable NLO polymer 65~85 C Lattice Hardening via Diels-Alder reaction: Isolated and low T crosslinking stablize the alignment 100 C Electric-Field Poling: Higher poling efficiency via effective site isolation Diene (Furan ring) Dienophile (Maleimide) Dendritic Moiety Dipolar NLO Chromophore

  26. A Fully-Functionalized Reversibly Thermally Crosslinkable NLO Polymer CLD-type Chromophore 15 wt% Furan Diene Protected Maleimide: Dormant Highly soluble polymer for purification and film casting Dendritic moiety for effective site isolation Luo & Jen, Adv. Mater., (submitted)

  27. Protected Maleimide: Dormant Highly soluble polymer for purification and film casting Maleimide after De-protection: Crosslinking Active

  28. r33 = 76 pm/V ( 15 wt% chromophore content) after two-stage (dissociation crosslinking) process: Resuming high poling effciency of our former side-chain dendronized NLO polymer (97 pm/V & 20 wt%) Jen et al, Adv. Mater., 14, 1763 (2002) Double Win! High Poling Efficiency Good Temporal Stability Thermally stable: ~80% of the orginal value can be retained at 70 C for more than 250 hrs. Without crosslinking: Only ~37% of the orginal value can be retained at 70 C for 144 hrs.

  29. The only difference is here, the diene part. Tunable temperature window achieved

  30. Double the performance of previous result Suitable for new device applications Such as optical interconnect (collaboration with USC)

  31. Synthesis of Trifluorovinyl Ether-containing Monomers and Dendrimers Ma & Jen et al., Proc. SPIE, 4805, 2002 (in press) Wong, Ma & Jen, Polymer Preprint, 43(2), 493 (2002); Macromolecules (in press)

  32. Low optical loss polymer Slight pressing and thermal molding S S S i i i Removing the mold P D M S S t a m p Optical Waveguides through Microcontact Printing (mCP) Jen and Xia Research Groups

  33. Coupler Waveguides through Microcontact Printing (mCP) 0.12 dB/cm @ 1.55 mm Chen, Zin, Ying, Xia & Jen, Macromolecules (in preparation)

  34. Arrayed Waveguide Gratings (AWGs) Fabricated Using Low Optical Loss Polymers

  35. ACKNOWLEDGMENT Sharon Wong Yadong Ying (Berkeley) Melvin Zin Dr. Hong Ma Dr. Jingdong Luo Sen Liu Marnie Haller Dr. Seok-Ho Kang Dr. Hong-Zhi Tang Dr. Seihum Kang Dr. Hongxian Li Dr. Xiaoming Wu (BFGoodrich) Dr. Takafumi Sassa (Univ. of Tokyo) Dr. Baoquan Chen (Lumera) Professors Larry Dalton, Younan Xia, Univ. of Washington Professor Chingfong Shu, National Chiao-Tung University, Taiwan Professor William Steier, USC Dr. John Kenney, Lightwave Microsystems Corp. AFOSR-MURI, NSF-NIRT, NSF-STC, DARPA, BMDO Boeing-Johnson Foundation, Lumera, Center for Nanotechnology, UW

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