Illinois Nano EP Seminar Series Fall 2011: Untangling the Essence of Bulk Heterostructure Organic Solar Cells: Why Complex Need not be Complicated

By Muhammad A. Alam

Electrical and Computer Engineering, Purdue University, West Lafayette, IN

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A new class of Macroelectronic devices appropriate for large area flexible electronics, supercapacitors, batteries, and solar cells rely on the biological dictum that 'form defines function' and use structural geometry to compensate for the poor intrinsic transport in materials processed at low temperature. Bulk heterostructure solar cells with two intertwined polymers acting as the acceptor/donor layers provide a striking example of such biomimetic design. Classical theories, originally developed for spatially homogenous media, cannot explain the key characteristics of such morphologically complex devices. Indeed, the optimization of this class of devices has long been stymied by a lack of theoretical tools that can treat the geometry of the structure at par with its transport characteristics In this talk, I will use theories of spinodal decomposition, geometric transform, and percolation models to demonstrate how simple ideas can untangle the complex (transport) geometry of BH solar cells. Our approach interprets the essential features performance and reliability of BH solar cells intuitively and establishes the fundamental principle of optimization and trade-off that must dictate the design of such devices.


Muhamad Ashraful Alam MUHAMMAD ASHRAFUL ALAM is a Professor of ECE at Purdue University where his research and teaching focus on physics, simulation, characterization and technology of classical and novel semiconductor devices. From 1995 to 2001, he was with Bell Laboratories, Murray Hill, NJ, as a Member of Technical Staff in the Silicon ULSI Research Department. From 2001 to 2003, he was a Distinguished Member of Technical Staff at Agere Systems, Murray Hill, NJ. He joined Purdue University in 2004.

Dr. Alam has published over 100 papers in international journals and has presented many invited and contributed talks at international conferences. He is a fellow of IEEE and APS and the recipient of 2006 IEEE Kiyo Tomiyasu Award for contributions to device technology for communication systems.


B. Ray, P. R. Nair, And M. A. Alam, "Morphology Dependent Short Circuit Current In Bulk Heterojunction Solar Cell", IEEE Photovoltaic Specialists Conference (PVSC), Hawaii, USA, 2010
B. Ray, P.R. Nair, R. E. García, M. Alam, "Modeling and optimization of polymer based bulk heterojunction (BH) solar cell", Proc. International Electron Devices Meeting (IEDM), Baltimore, USA, 2009, Also available in presentation form.
M. Alam, Nanostructured Electronic Devices: Percolation and Reliability, 2009 NCN@Purdue Summer School: Electronics from the Bottom Up

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Researchers should cite this work as follows:

  • Muhammad A. Alam (2011), "Illinois Nano EP Seminar Series Fall 2011: Untangling the Essence of Bulk Heterostructure Organic Solar Cells: Why Complex Need not be Complicated,"

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MNTL 1000, University of Illinois, Urbana, IL


Javid Mohammed Ali

University of Illinois at Urbana-Champaign