Thrust on Organic Electro-Optic and All-Optical Materials and Devices

1. Thrust on Organic Electro-Optic and All-Optical Materials and Devices ACHIEVEMENT: Porphyrin polymers exhibit large microscopic and macroscopic third-order nonlinearities throughout telecommunication window (1300-1550 nm). IMPACT: Largest nonlinearities to date in NIR demonstrate potential for all-optical signal processing at >100 Gbs for either integrated device applications or free space applications. Films of porphyrin polymers show large, ultrafast (<10 ps) |(3)| (>2x10-10 esu) throughout NIR regionwith Pb polymer exceeding 1x10-9 esu at 1.3 m - meeting (3) goal for all-optical switching Collaboration with Dr. Anderson, Oxford University Aryl substituents provide excellent solubility such that highly concentrated solutions could be used for (3)-based free space signal processing Strongly coupled conjugated macrocycles Porphyrin bis-acetylide polymers Supramolecular assembly of polymers gives >3x enhancement in nonlinearity of Zn polymer Perry (GIT) et al., in preparation.

2. Thrust on Organic Electro-Optic and All-Optical Materials and Devices ACHIEVEMENT:Significant advances have been made in the application of new quantum and statistical mechanical methods to the quantitative simulation of linear and nonlinear optical properties. Real-time time-dependent density functional theory (RTTDDFT) has been adapted to the quantitative simulation of the dispersion and dielectric dependence of linear and nonlinear molecular optical properties. Pseudo-atomistic Monte Carlo calculations have yielded quantitative simulated of electro-optic data for a variety of organic materials (polymer, dendrimer, and binary chromophore glasses). 2nd Order NLO Activity Linear Absorption Spectrum

3. Thrust on Light Sources and Organic Electronics ACHIEVEMENT: n-channel organic field-effect transistors have been fabricated with fullerenes. The devices exhibit charge mobility values of up to 5 cm2/Vs (10 x improvement over a-Si), have on-off ratios > 106 and have threshold voltages near zero. In addition, the devices are stable under continuous bias and repeated cycling. IMPACT While a-Si yields only efficient n-channel thin-film transistors, organic semiconductors led so far to efficient p-channel transistors. For complementary designs of low-power circuits both n- and p-channel transistors with comparable performance are a pre-requisite. The demonstration of efficient n-channel transistors will allow for the design of inverters, logic gates and ring oscillators with unprecedented performance that can be processed at room temperature onto low cost flexible substrates. Appl. Phys. Lett. 91, 092114 (2007)

4. 500 nm Thrust on Light Sources and Organic Electronics • Photoconductive Atomic Force Microscopy is used to study the performance of polymer solar cells • Variations indicate that further optimizing morphology can still yield significant performance gains • Evidence for losses are seen at polymer/anode contact Nano Letters7, 738 (2007)

5. L4 L3 L2 Thrust on Light Sources and Organic Electronics ACHIEVEMENT:. A novel ultrafast image correlation technique has been developed using efficient third-harmonic generation in organic thin films. IMPACTBackground free image correlation using third harmonic generation allows for signal to noise ratio superior to those employing degenerate four-wave mixing. This demonstration paves the way to ultrafast optical image processing. Opt. Lett. 32, 2599, (2007) Appl. Phys. Lett. 91, 131110 (2007)

6. DIVERSITY PROGRAMS ACHIEVEMENT:CMDITR leads the GEM-STC partnership at the 2007 National GEM conference, Las Vegas, NV, October 4-6, 2007. To improve the diversity of graduate students in STCs, CMDITR collaborates with GEM and seven other STCs in the GEM-STC Partnership. CMDITR’s leadership at the 2007 National GEM conference means improved recruiting and retention of underrepresented graduate students into all STCs. • Improved research and career competitiveness • Tools and metrics for career planning • A powerful network of peers • Mentoring all students, especially members of underserved populations

7. New Online Resources for 2007: Ask advance questions of the speaker Participate in the discussion forum for the event Listen to audio recordings of selected speakers DIVERSITY PROGRAMS ACHIEVEMENT: The CMDITR Leadership Lunch Series, developing leadership potential in women and underrepresented minority students and postdocs, expands its reach with interactive and multimedia online resources across three campuses. What is Leadership Lunch? Leadership lunch events are invited, monthly talks at U Washington, U Arizona, and Georgia Tech, featuring women and minority researchers from engineering, math, and the sciences. The talks are given in an informal, round-table setting to discuss a variety of topics.  A primary goal of the series is information exchange to discuss topics such as career options, other opinions and vantage points, and ideas for ways to address present challenges and achieve future goals. Recent leadership lunch series speakers from University of Washington, University of Arizona, and Georgia Institute of Technology. http://www.stc-mditr.org/leadershiplunch/

8. EDUCATION AND PARTNERSHIP PROGRAMS ACHIEVEMENT: Norfolk State University’s new Ph.D. student class benefits from five-day workshop given by Georgia Tech researcher Demetrio Filho, October 2007. Norfolk State University Ph.D. students participate in the Demetrio Filho workshop at Georgia Tech.

9. EDUCATION AND PARTNERSHIP PROGRAMS ACHIEVEMENT: CMDITR builds new Norfolk State University Ph.D. program by investing in course development as well as acculturation of students into graduate student life. CMDITR partner Norfolk State University received Center funding for their “Engaging Graduate Students Beyond Lab and Lecture: We All Benefit” proposal. The purpose of the project is to enhance the infrastructure, academic programs, graduate students’ experiences, and public awareness of graduate programs at NSU. This program is projected to have far-reaching implications in strengthening NSU’s new PhD program in Material Science and Engineering, with outcomes transferable to graduate programs at other institutions.

10. EDUCATION AND PARTNERSHIP PROGRAMS ACHIEVEMENT: CMDITR summer research experiences for undergraduates leads to their high enrollment in graduate school in later years. The program targets “gateway” students, especially community college students, early undergraduates in non-research institutions and minority students. CMDITR “Hooked on Photonics” 2004-2007: Four years of summer REU • 94 undergraduate participants (2004-07) • over 50% women (2004-07) • over 50% rising sophomores & juniors (2006-07) • over 40% minority (2007) • 100% transfer rate, community college AS graduates to 4-year or comprehensive institutions (2004-07) • 67% enrollment rate, Bachelor graduates to graduate school (2004-07) “Hooked on Photonics” participants, Summer 2007, Georgia Tech campus.