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M.A. Rose, 2008

Leveraging the Experimental Method to Inform Solar Cell Design. Mary Annette Rose Jason Ribblet Heather Hershberger International Technology Education Association February 22, 2008, 2:00-2:50, Room 251E. M.A. Rose, 2008. Science-Technology Enterprise. Symbiotic Relationship.

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M.A. Rose, 2008

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  1. Leveraging the Experimental Method to Inform Solar Cell Design Mary Annette Rose Jason Ribblet Heather Hershberger International Technology Education Association February 22, 2008, 2:00-2:50, Room 251E M.A. Rose, 2008

  2. Science-Technology Enterprise Symbiotic Relationship Mutual Dependence Images: The School of Science and Engineering, The University of Waikato. Retrieved http://sci.waikato.ac.nz/about_the_school.shtml

  3. Thin-Film Solar Cells Collaboration of the National Renewable Energy Laboratory & Heliovolt to develop a solar cell using a copper-indium-gallium selenide (CIGS) semiconductor. Scientific challenge: to understand the chemistry and microscopic structure of the material in order to optimize its electrical properties. Engineering challenge: develop a reliable manufacturing process—akin to a printing process— that produces standard size modules (15 & 30-cm wide). Bullis, K., (2007). Making cheaper solar cells. Technology Review. Wednesday, September 12, 2007. Retrieved January 23, 2008, from http://www.technologyreview.com/Energy/19369/page1/

  4. Challenge for Technology Education Science Content & Process Technology Content & Process

  5. Presentation Goal Photochemistry Solar Cells Inquiry: Experimentation Design

  6. Cuprous Oxide Solar Cell

  7. Observing Phenomena Stimulate intellectual curiosity • What is happening in this system? • What energy is at work here? • What are the inputs, processes, and outputs of the system? • What happens if we block the cell from the sun? • What happens when we reverse the probes of the multimeter on the plates of the cell?

  8. Parts & Materials List Component Function Parts Material Qty - Size Case Water–tight transparent housing Front/Back 1/8” Acrylic 2 pcs of 4 1/8”” x 4 1/8” Sides/Bottom 1/8” Acrylic 1 pc of ½” x 12” Plates Anode and Cathode Cuprous Oxide Cupric Oxide 0.20” Copper, Unpolished 2 pcs of 3 7/8” x 5” Salt Solution Medium of ion exchange Salt (NaCl reagent grade) 15% NaCL or 17.6 g Distilled Water 85% H2O or 100 ml Solar Cell: Photoelectric Effect

  9. Challenge Students to… • Take on the role of a photochemist • Learn how solar cells convert light into electricity • Inform cell design

  10. Photochemistry is… • study of chemical reactions of molecules in excited states produced by the absorption of light energy, i.e., photon • infrared (700–1000 nm) • visible (400–700 nm) • ultraviolet (200–400 nm) • electron transfer and ionization

  11. Challenge Students to… • Take on the role of a photochemist • Learn how solar cells convert light into electricity • Inform cell design • Plan, implement, and interpret an experiment

  12. Experiment: Method for Investigating Variables To what extent does the distance from the light source effect the power production of solar cells? Cause Effect Independent Variable Dependent Variable Outcome Variable Treatment Variable

  13. What variables influence the power output of the cell? List Variables & Identify Elements • Concentration of salt solution • Distance between plates (E) • Surface area of plate (Cu2O and CuO) • Type of light (frequency) • Intensity of the light • Thickness of copper plate

  14. What question might we experimentally test?

  15. Form Teams and Assign to Treatment Conditions Sam Bob Inga Fran Ted Harry Treatment Group 1 5% Solution 2 1 Ted Laura Elsa Howard Sally Frank Treatment Group 2 15% Solution 3 4 Bill Jean Remi Martha Rex Harris Treatment Group 3 25% Solution 6 5

  16. Day 2 & 3: Manufacture Cells Specifications Top/Back: C x B Side: D x (2B+C) Plate: F x A A = 5” B = 4 1/8” C = 4 1/8” D = 1/2” E = 3/16” F = 3 7/8”

  17. Homework: Literature Review Students discover more about… semi-conductive materials, the photoelectric effect, the interaction of energy and materials, and solar (photovoltaic) cells.

  18. Day 2 & 3: Manufacture Cells Process Sheet Metal

  19. Chemical Safety For laboratory safety, see the National Institute for Occupational Safety (NIOSH, 2006).

  20. Heat Copper Plate

  21. Heat Promotes Copper Oxidation

  22. Layer of Cupric Oxide (Black)

  23. Acrylic Processing

  24. Assemble the Case

  25. Test for Leaks

  26. Day 4: Procedure for Data Gathering Stimulate planning • What procedure will we use to test the cells? • How can we assure systematic and consistent testing conditions? • Why does a scientist strive for consistent experimental conditions? Set-UP Measuring Recording

  27. Procedure for Data Gathering

  28. Data Analysis

  29. Recording Data

  30. Data Gathering

  31. Recording Data

  32. Interpreting the Results • Level of salt in the solution impacts performance with best performance occurring at 15% • Tilt impacts performance with 90° tilt (perpendicular) consistently position resulting in best performance • The best performing combination of factors was a 15% solution at 90° tilt

  33. The Photoelectric Effect h= Planck’s Constant v = frequency 1 eV = 1.6 x 10-19 joules Yaqoob, T. (n.d.). Photoelectric effect [Image]. John Hopkins University. Retrieved from http://www.pha.jhu.edu/~yaqoob/8m/lecture2/photoelectric_1.gif

  34. Atomic States: Ground vs. Excited

  35. What is happening in the solar cell? • Excitation of a Cu2O: • Negatively charged ions move through circuit, • Positively charged ions break free, and • Combine on the raw copper plate.

  36. Solid State PV Cell Michell, R. (2000). A Seimens crystalline PV cell. WisconSUN. Retrieved from http://www.wisconsun.org/learn/learn_intro.shtml; Renewable Energy Works. (n.d.) Photovoltaics.[Image]. Retrieved 3/10/06, from http://www.renewableenergyworks.com/pv/PVDefn/PVDefn.html

  37. Learn More

  38. Let’s Make Connections & Review !!

  39. Alignment to National Standards

  40. Characteristics of Experimental Designs • Pose a research question which identifies the treatment (IV) and an outcome (DV) variable. • Select & assign a sample to treatment conditions • Experimental group (Receives treatment) • Control group (No treatment) • Comparison groups (Different Levels of treatment) • Apply treatment to one or more groups • Control extraneous variables • Measure outcomes • Statistically describe and represent the data • Statistically test the hypothesis

  41. Inquiry is a Search for Understanding • Spurred by intellectual curiosity • Process is characterized by … • observing phenomena • asking questions and hypothesizing • systematically gathering and analyzing data • theorizing about the meaning of the evidence • Enabled by objective, measurable, and replicable methods

  42. Best Practices & Scaffolding • Initiate intellectual curiosity • Ask questions, and encourage students to form questions • Provide increasingly more complex models (conceptual-to-realistic) of the photoelectric effect • Provide visual examples and simulations of photochemical processes • Provide access to diverse resources, e.g., chemistry and physics • Guide students through experimentation: sampling, hypothesizing, identifying variables, planning procedures, analyzing data, interpreting data • Require sense-making activities, such as collaborative discussion and the creation of cause and effect diagrams • Require students to apply experimental findings to the re-design of a solar cell.

  43. Contact …. Mary Annette Rose Ball State University arose@bsu.edu 765-285-5648 http://arose.iweb.bsu.edu

  44. Leveraging the Experimental Method to Inform Solar Cell Design Mary Annette Rose Jason Ribblet Heather Hershberger International Technology Education Association February 22, 2008, 2:00-2:50, Room 251E M.A. Rose, 2008

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