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Organic Solar Cells. Blair Knutson. Dr. Baskar Ganapathysubramanian , Hari Kodali , Olga Wodo , Kahntinetta Pr’Out. Outline. Motivation and objectives: The Why and What Silicon vs. Organic The Problems Solutions Drift-Diffusion Model Langevin relation and Interfacial recombination
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Organic Solar Cells Blair Knutson Dr. BaskarGanapathysubramanian, HariKodali, Olga Wodo, KahntinettaPr’Out
Outline • Motivation and objectives: The Why and What • Silicon vs. Organic • The Problems • Solutions • Drift-Diffusion Model • Langevin relation and Interfacial recombination • What I do…
The Why and What? • Why work with organic solar cells when silicon-based solar cells are more efficient? • What is the research goal? http://www.icanfixupmyhome.com/images/SolarPanelDynamixDIY.jpg http://www.siemens.com/innovation/pool/en/publikationen/publications_pof/PoF_Spring_2005/Organic_Solar_Cells/szenbild_1267649.gif
Silicon vs. Organic • The differences between silicon and organic solar cells Silicon Solar Cell Organic Solar Cell http://deibel.files.wordpress.com/2008/03/osc-bhj-morphology-scheme-generation-and-transport.png?w=196&h=280 http://www.pveducation.org/pvcdrom/solar-cell-operation/solar-cell-structure
The Problems • Recombination • Monomolecular : disordered material have traps that cause recombination • Negligible in P3HT:PCBM • Bimolecular: recombination of holes and electrons from the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) • Morphology • “Kahni’s department” http://deibel.files.wordpress.com/2008/03/osc-bhj-morphology-scheme-generation-and-transport.png?w=196&h=280
Solutions • The morphology (mixture of fullerene and polymer) needs to be determined for the best efficiency • The recombination needs to be modeled in order to determine how to reduce recombination • Use of the Langevin model for bimolecular recombination • Determination of interfacial recombination
Drift-Diffusion Model • The equations are used to solve for the potential and carrier diffusion coefficient (1-dimensional) Poisson’s equation Current Continuity Equations Drift and Diffusion of Charge carriers Koster, e. a. (2005). Device model for the operation of polymer/fullerene bulk heterojunction solar cells. Physical Review , 1-9.
Langevin relation and interfacial recombination • Equations used to find the Bimolecular Recombination rate Langevin recombination constant (use of slowest carrier) Interface recombination coefficient Bimolecular recombination rate Kodali, H. (2010). Summary of recombination models. Koster, e. a. (2006). Biomolecular recombination in polymer/fullerene bulk heterounction solar cells. Applied physics letters , 88-90. • Szmytkowski. (2009). Analysis of the image force effects on the recombination at the donor-acceptor interface in organic bulk heterojunction solar cells. Chemical Physics Letters , 123-125.
What I do…… • First, I learned the basics of Organic Solar Cells • Now I am learning programming in C++ • The goal: Use the various recombination equations to produce an accurate model of the organic solar cell clipart
Questions? clipart