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Alan J. Heeger LECTURE 1 LECTURE 2 We demonstrate by a series of transient absorption measurements that the Uncertainty Principle can enable ultrafast (<100 fs) charge transfer over distances of 10-20 nm in the nanoscopically THE UNIVERSITY OF AKRON textured material in bulk heterojunction (BHT) solar cells. DEPARTMENT OF POLYMER ENGINEERING Because the spatial extent of the initially photoexcitated wavefunction is determined by the Uncertainty Principle, not by the eigenfunctions of the Schrodinger equation describing the disordered nanostructured material, we expect the emergence of new physics in nanoscience. I will focus on the details of the operating mechanism; the origin of the open circuit voltage (voc), the role of morphology on the charge separation and charge collection at the electrodes, the need for charge selective buffer layers and the origin of the limitations on the fill factor (FF). I will emphasize the importance of the competition between sweep-out and recombination and on studies of recombination mechanism in BHJ solar cells. Recent results on BHJ solar cells using small molecule donors (rather than polymers) will be briefly summarized. PRESENTS BAYER LECTURESHIP About Bayer Alan J. Heeger Bayer is a global enterprise with core competencies in the Nobel Laureate in Chemistry, 2000 fields of health care, nutrition and high-tech materials. Bayer Professor of Physics and MaterialScience LLC is one of the leading producers of Professor of Materials at the polymers and high-performance plastics in North America and University of California, Santa Barbara is part of the global Bayer MaterialScience business with approximately 14,800 employees at 30 production sites around the world and 2011 sales of 10.8 billion euros. Bayer LECTURE 1 MaterialScience’s 2011 sales in North America were $2.9 Thursday, May 9, 2013 billion. The company manufactures high-tech polymer materials 10:30 a.m. and develops innovative solutions for products used in many STUDENT UNION THEATER areas of daily life. The main segments served are the automotive, electrical and electronics, construction, medical, Room 210 and sports and leisure industries. Sustainability is central to “Creativity, Discovery and Risk: Bayer MaterialScience LLC’s business and is based around the Nobel Prizes Past and Future “ key areas of innovation, product stewardship, excellence in corporate management, social responsibility and respect for the environment. LECTURE 2 Friday, May 10, 2013 11:00 a.m. STUDENT UNION THEATER Room 210 “The Role of the Heisenberg Uncertainty Principle in Bulk Heterojunction Solar Cells” SPONSORED BY BAYER MATERIALSCIENCE, PITTSBURGH BAYER LECTURESHIP IN Our subsequent discovery of metallic levels of electrical POLYMER ENGINEERING conductivity in polyacetylene demonstrated that our ideas were both true and revolutionary; the field of semiconducting and metallic polymers had been created. Semiconducting and metallic polymers: In the beginning --- dirty materials that were complex and poorly characterized. My physicist friends thought that I was crazy --- thus serious risk. Great discoveries can be found by exploring new directions in interdisciplinary science. Moving into such new directions required going beyond my core knowledge and therefore involved serious Risk. I lived with that risk for 24 years and created a new field at the boundary between physics and chemistry. I was born a physicist. People even tell me that I look like a physicist. But we are what we have become --- with the award of the Nobel Prize in Chemistry in 2000, I became a Chemist. Prof. Alan J. Heeger serves as Professor of Physics and Professor of Materials at the University of California, Santa Barbara and also What is next? heads a research group at the university’s Center for Polymers and Organic Solids. He was awarded the Nobel Prize in Chemistry science. Mrs Heeger and I have participated in the production (2000) for his pioneering research in and the co-founding of the field • Entrepreneurialof plays on the Broadway Activities Theatre.and Theatre I have Activities performed and (with more my of semiconducting and metallic polymers; his research efforts colleague David Gross--- NP in Physics in 2004) --- in the play continue to focus on the science and technology of semiconducting “Copenhagen”. I played the part of Niels Bohr. and metallic polymers. Contact: Department of Physics, University of California, Santa Barbara, CA 93106-9530; [email protected]. Start-up companies edu; www.cpos.ucsb.edu • UNIAXBankrupt, ----- but polymer R&D all LEDs over the world THURSDAY, MAY 9, 2013 • Konarka“Plastic” Bulk heterojunction solar cells -- "Creativity, Discovery and Risk: Capture circulating tumor cells (CTCs) in the blood and find Nobel Prizes Past and Future " • Cynveniothe specific --- genetic Cancer mutationsdiagnostic thatusing are the the “Liquid cause Biopsy”:of the cancer. Advice to the Nobel Laureates of the Future. Perhaps the greatest pleasure of being a scientist is to have an abstract idea, then to do a series of experiments which demonstrate that the idea was correct --- To demonstrate that Nature actually behaves as conceived in the mind of the scientist. • Cherish creativity! • Beinvolve bold Risk.and have the audacity to seek to discover! • Remember that creativity and discovery necessarily I will start with a story from my childhood illustrating “creativity, Dealing with that risk is part of the thrill and satisfaction of discovery and risk” at the age of four. My story which describes an “experiment” with a set of toy soldiers, a toy canon and the use of living a life in science. matches as projectiles was the very first time that I experienced this intense pleasure; the essence of creativity in science. FRIDAY, MAY 10, 2013 “The Role of the Heisenberg Uncertainty In science, creativity and discovery are related, but they are not the same. Scientific breakthroughs result from a combination of Principle in Bulk Heterojunction Solar Cells” creativity and discovery. Watson and Crick discovered the structure of DNA, the Secret of Life. Arno Penzias and Robert I will describe the discovery of ultrafast photoinduced electron Wilson made a Marvelous discovery! Their creativity: The transfer as the scientific foundation for the creation of a technology invention of very low noise microwave amplifiers. Their discovery: for low cost “plastic” solar cells. This initial charge separation They pointed their low noise amplifier into the night sky ---and occurs at a time scale two orders of magnitude faster than the discovered the black-body radiation that is the residual of the Big first step in photosynthesis in green plants. Bang at the creation of the Universe ! Albert Einstein created the idea of curved space-time as equivalent to, and the origin of, “Plastic Solar Cells” gravity. When, during the solar eclipse of 1919, light was observed to actually curve around the sun, Einstein became deservedly The ultrafast electron transfer in polymer BHJ famous. Again --- creativity and discovery! Materials and in small molecule BHJ Materials is enabled by the Uncertainty Principle My experiments with the canon and the toy soldiers were the first indications that I might have a future as a scientist. Many years later, Alan MacDiarmid, Hideki Shirakawa and I had the idea that we could make polymers ---“Plastics” --- long chain macromolecules that would conduct electricity and exhibit the electrical and optical properties of metals and semiconductors. continued on back.
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