Events
Excitonic Processes in Nanostructured Optoelectronic Devices
April 1, 2009 at 3pm/36-428
Vladimir Bulovic
Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology
abstract:
Nanoscale materials such as molecules, polymers, and nanocrystal quantum dots can be assembled into large area functional optoelectronic devices that can surpass the performance of today’s state-of-the-art technologies. Advances in thin film processing of nanostructured material sets and concomitant development of physical models of nanostructured device operation are rapidly advancing this science and engineering field. This talk will highlight the contribution of excitonic processes in the optical and electrical response of nanostructured optoelectronic devices, singling out the exciton diffusion as the dominant governing process in many active structures. In light emitting diodes, exciton diffusion affects the degree of cascade energy transfer and the color saturation, and in solar cells, photodetectors, and chemosensors, exciton diffusion to interfaces is the central process in determining the exciton dissociation efficiency, and the consequent photogeneration efficiency. The talk will illustrate excitonic behavior using both specific technology examples, as well as by describing model structures that highlight the origin and influence of exciton energy disorder, the exciton dynamics in mixed excitonic systems, and the related challenges in measuring the exciton diffusion length.
bio:
Professor Vladimir Bulovic is a principal investigator in the Research Laboratory of Electronics (RLE) at the Massachusetts Institute of Technology (MIT). He graduated from Princeton University with a B.S.E. (1991), M.A. (1995), and Ph.D. (1998) in Electrical Engineering. He joined the faculty of MIT in 2000 as an Assistant Professor of Electrical Engineering and Computer Science. His research interests include studies of physical properties of organic and organic/inorganic nanodot composite thin films and structures, and development of novel optoelectronic organic and hybrid nano-scale devices. In 2004, Professor Bulovic was named as one of the TR100, the list of top young innovators in technology named annually by Technology Review magazine. In the same year, he also was awarded the Presidential Early Career Award (PECASE), the nation’s highest honor for scientists and engineers at the beginning of their research careers.
Prior to joining MIT, Professor Bulovic was a Senior Scientist and Project Head of Strategic Technology Development at Universal Display Corporation (UDC). At UDC he worked on the application of organic materials to LEDs for full color flat panel displays and thin film photovoltaics for solar cell and detector applications. His work resulted in development of OLED backlights, pixilated arrays of stacked OLEDs, and improved performance of phosphorescent OLEDs. Prior to joining UDC he worked in Princeton’s POEM Center as a graduate researcher (1993-1998) and research associate (1998-1999). At Princeton, Professo Bulovic participated in a series of projects examining optical and electrical properties of vacuum deposited amorphous and crystalline molecular organic thin films and devices. His work resulted in development of OLED technologies such as transparent, inverted, and stacked OLEDs, demonstration of the first optically pumped organic semiconductor lasers, and understanding of photogeneration in organic photovoltaic devices, microcavity effects in luminescent devices, and the solid state solvation effects in polar organic media. From 1991-1993, Professor Bulovic worked at Columbia University’s Microelectronics Sciences Laboratory, where for he examined image-potential states and resonances on metal surfaces utilizing non-linear two-photon photoemission spectroscopy.
