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CEAS REU Project 4 Synthesis of Solar Cell Materials, and Fabrication of Novel Polymer-Based Solar Cells. Nathan Duderstadt , Chemical Engineering, University of Cincinnati Stoney Sutton, Electrical Engineering, University of Cincinnati Kate Yoshino, Engineering Physics, Taylor University
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CEAS REU Project 4Synthesis of Solar Cell Materials, and Fabrication of Novel Polymer-Based Solar Cells Nathan Duderstadt, Chemical Engineering, University of Cincinnati Stoney Sutton, Electrical Engineering, University of Cincinnati Kate Yoshino, Engineering Physics, Taylor University Advisors: Ms. Yan Jin and Dr. VikramKuppa Grant ID No.: DUE-0756921
Introduction • Why solar cells? • Why ORGANIC solar cells? • What is graphene and what role does it play?
Background Literature Review Solar Radiation Charge Generation Charge Transport to Electrodes In a semiconductor, the energy from the sun both moves the electron to an excited state, but also creates a hole (positive charge) in its place. Electric Current Lowest Unoccupied Molecular Orbital Highest Occupied Molecular Orbital e h Animation and concepts adapted from Dr. VikramKuppa’s presentation on organic photovoltaics
Organic Photovoltaic Devices • Problems with OrganicSemiconductors: • Charge Separation • Charge Transfer • Solutions: • Bulk-heterojunction structured active layer • Graphene Picture from: Deibel, Carsten, and Vladimir Dyakonov. (2010). " Polymer–fullerene Bulk HeterojunctionSolar Cells.." Vol. 73.9, pp. 1-39.
So, Why Graphene? Atomic Force Microscopy Image of 0.045 mg/ml 300 mesh graphene solution • High aspect ratio • Conductivity • Enables lower concentration of graphene • Charge transport • Hole AND Electron • Drawbacks • Increase recombination • Difficult to control morphology
Cell Structure Aluminum (Cathode) Lithium Fluoride Active Layer (P3HT:F8BT:Graphene) PEDOT:PSS Indium Tin Oxide (Anode) Glass Slide The thickness of the cell is approximately without the glass slide is approximately 500 nm in thickness.
Cell Structure Solar Cell Active layer Indium Tin Oxide (Anode) Aluminum (Cathode) Glass Slide
Goals and Objectives • Learn the basics of Organic Photovoltaic (OPV) research • Gain expertise in making and characterizing OPV cells • Differentiate between processing techniques and their influence on the solar cell • Evaluate graphene content on cell performance We aim to determine how graphene makes solar cells more efficient.
Tasks Learn methods for making graphene solutions and fabricating solar cell devices Prepare and analyze graphene solutions for use in solar cell polymers Fabricate solar cell devices and perform thermal treatment Characterize the cell through various testing Conduct morphology and conductivity studies on the polymer films with different graphene concentrations Report writing and presentations
Timeline and Schedule Week Task ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓
Conductivity Testing Parameters: • Graphene concentration • Application method • Electrode configuration • Graphite type • Sonication amount
Conductivity: Semiconductor Curve Polymer blends applied by drop casting, then spinning at very low rates
Varying Graphene Polymer blends applied by spinning coating at very low rates
Conductivity Summary • Just vertical, no lateral • Spin coating, not drop casting • Spin coat at low rates for longer periods of time for thicker cells
Future Steps • Find appropriate graphene concentration • Verify tentative results • Apply to solar cell studies
References Chen,Y., Liu,Q., Liu, Z., et al., (2009). "Polymer Photovoltaic Cells Based on Solution-Processable Graphene and P3HT." Advanced Functional Materials Journal, Vol. 19,No.6, pp. 894-904. Deibel, C, and V. Dyakonov. (2010). "Polymer–fullerene Bulk Heterojunction Solar Cells," Reports on Progress in Physics, IOP, Vol. 73, No. 9, pp. 1-39. Li,G., Yang,Y., and R. Zhu.(2012). "Polymer Solar Cells." NATURE PHOTONICS No.6, pp.153-161. McNeill, C.R., et al. (2007). , “Influence of Nanoscale Phase Separation on the Charge Generation Dynamics and Photovoltaic Performance of Conjugated Polymer Blends: Balancing Charge Generation and Separation.” Journal of Physical Chemistry C, Vol. 111, No. 51, pp. 19153-19160.
References Saricifti, N.S. (2001). “Plastic Solar Cells.” Abstracts of Papers of the American Chemical Society, Vol. 222, pp. U281-U281. Shin, M., H. Kim, and Y. Kim. (2011). “Effect of film and device annealing in polymer:polymer solar cells with a LiFnanolayer.” Materials Science and Engineering B- Advanced Functional Solid-state Materials, Vol. 176, No. 5, pp. 382-386. Wan, X., Guiankui L., Lu H., and Y.Chen. (2011), “Graphene- A Promising Material for Organic Photovoltaic Cells.” Advanced Materials, Vol. 23, pp. 5342-5358. Yu, D., et al. (2010), “Soluble P3HT-Grafted Graphene for Efficient Bilayer- Heterojunction Photovoltaic Devices.” ACS Nano, Vol. 4, No. 10, pp. 5633-5640.
Questions? Thank you!