Presentation on theme: "M.A. Rose, 2008 Leveraging the Experimental Method to Inform Solar Cell Design Mary Annette Rose Jason Ribblet Heather Hershberger International Technology."— Presentation transcript:
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 Images: The School of Science and Engineering, The University of Waikato. Retrieved http://sci.waikato.ac.nz/about_the_school.shtml Symbiotic Relationship Mutual Dependence
M.A. Rose 2008 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.National Renewable Energy Laboratory 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/http://www.technologyreview.com/Energy/19369/page1/
M.A. Rose 2008 Challenge for Technology Education Science Content & Process Technology Content & Process
M.A. Rose 2008 Presentation Goal Photochemistry Solar Cells Inquiry: Experimentation Design
M.A. Rose 2008 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?
M.A. Rose 2008 Solar Cell: Photoelectric Effect Parts & Materials List ComponentFunctionPartsMaterialQty - Size CaseWater–tight transparent housing Front/Back1/8” Acrylic2 pcs of 4 1/8”” x 4 1/8” Sides/Bottom1/8” Acrylic1 pc of ½” x 12” PlatesAnode 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 Water85% H 2 O or 100 ml
M.A. Rose 2008 Challenge Students to… Take on the role of a photochemist Learn how solar cells convert light into electricity Inform cell design
M.A. Rose 2008 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)ultraviolet electron transfer and ionization
M.A. Rose 2008 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
M.A. Rose 2008 Experiment: Method for Investigating Variables CauseEffect Independent Variable Dependent Variable To what extent does the distance from the light source effect the power production of solar cells? Treatment Variable Outcome Variable
M.A. Rose 2008 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 (Cu 2 O and CuO) Type of light (frequency) Intensity of the light Thickness of copper plate
M.A. Rose 2008 What question might we experimentally test? VariablesQuestion Concentration of salt solution Distance between plates (E) Surface area of plate (Cu 2 O and CuO) Type of light (frequency) Tilt of cell to light source Intensity of the light Thickness of copper plate Type of plate How does the concentration of the salt solution (IV) effect the electrical power output (DV) of the cell? How does the concentration of the salt solution (IV) and the tilt of the cell (IV) effect the electrical power output (DV) of the cell?
M.A. Rose 2008 Form Teams and Assign to Treatment Conditions Treatment Group 1 5% Solution Treatment Group 2 15% Solution Treatment Group 3 25% Solution Ted Laura Elsa Howard Sally Frank Fran Ted Harry Sam Bob Inga Martha Rex Harris Bill Jean Remi 1 2 3 4 5 6
M.A. Rose 2008 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”
M.A. Rose 2008 Homework: Literature Review Students discover more about… semi-conductive materials, the photoelectric effect, the interaction of energy and materials, and solar (photovoltaic) cells.
M.A. Rose 2008 Day 2 & 3: Manufacture Cells Process Sheet Metal
M.A. Rose 2008 Chemical Safety HazardsSafety Practices Nitric Acid (oxidizing agent) corrosive and reactive, teacher should prepare and handle the solution, store alone in storage cabinet Acrylic Adhesive methylene chloride volatile: inhalation hazard skin irritant Cupric oxide (black powder) skin irritant Handle in a well-ventilated area. Wear chemical splash goggles. Wear neoprene gloves and clothing protection. If directly exposed, flush the affected area with water. For laboratory safety, see the National Institute for Occupational Safety (NIOSH, 2006).
M.A. Rose 2008 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
M.A. Rose 2008 Procedure for Data Gathering Setting-upMeasuringRecording 1. Specify light source 2. Relative position of cell to light source 3. Charging the cell 1. Attaching alligator clips/probes to multimeter 2. Adjusting function & range 3. Reading meter
M.A. Rose 2008 Recording Data Treatment IV-1 Treatment IV-2 Dependent DV-1 Dependent DV-2 Dependent DV-3 Team Salt Solution (IV-1) Angle of Test (IV-2) Voltage (mV) Current (μA) Power (mW) 15%30° 25%45° 315%30° 415%45° 525%30° 625%45°
M.A. Rose 2008 Recording Data Treatment IV-1 Treatment IV-2 Dependent DV-1 Dependent DV-2 Dependent DV-3 Team Salt Solution (IV-1) Tilt (IV-2) Voltage (mV) Current (μA) Power (μW) 15%90°2288 1.94 25%45°1074 0.74 315%90°45346 15.57 415%45°29282 8.18 525%90°40216 8.64 625%45°30192 5.76
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
M.A. Rose 2008 The Photoelectric Effect Yaqoob, T. (n.d.). Photoelectric effect [Image]. John Hopkins University. Retrieved from http://www.pha.jhu.edu/~yaqoob/8m/lecture2/photoelectric_1.gif http://www.pha.jhu.edu/~yaqoob/8m/lecture2/photoelectric_1.gif h = Planck’s Constant v = frequency 1 eV = 1.6 x 10 -19 joules
M.A. Rose 2008 Atomic States: Ground vs. Excited
M.A. Rose 2008 What is happening in the solar cell? Excitation of a Cu 2 O: Negatively charged ions move through circuit, Positively charged ions break free, and Combine on the raw copper plate.
M.A. Rose 2008 Solid State PV Cell Michell, R. (2000). A Seimens crystalline PV cell. WisconSUN. Retrieved from http://www.wisconsun.org/learn/learn_intro.shtml;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 http://www.renewableenergyworks.com/pv/PVDefn/PVDefn.html
M.A. Rose 2008 Let’s Make Connections & Review !!
M.A. Rose 2008 Alignment to National Standards Standards for Technological Literacy (ITEA, 2000) National Science Education Standards (NRC, 1996) Inquiry & Experi- mentation 10. Students will develop an understanding of the role of troubleshooting, research and development, invention and innovation, and experimentation in problem solving. As a result of the activities in grades 9-12, all students should develop: Abilities to do scientific inquiry Understanding about scientific inquiry Energy 16. Students will develop an understanding of and be able to select and use energy and power technologies. As a result of the activities in grades 9-12, all students should develop an understanding of: Structure and properties of matter Chemical reactions Interactions of energy and matter
M.A. Rose 2008 Characteristics of Experimental Designs 1. Pose a research question which identifies the treatment (IV) and an outcome (DV) variable. 2. Select & assign a sample to treatment conditions –Experimental group (Receives treatment) –Control group (No treatment) –Comparison groups (Different Levels of treatment) 3. Apply treatment to one or more groups 4. Control extraneous variables 5. Measure outcomes 6. Statistically describe and represent the data 7. Statistically test the hypothesis
M.A. Rose 2008 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
M.A. Rose 2008 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.
M.A. Rose 2008 Contact …. Mary Annette Rose Ball State University firstname.lastname@example.org 765-285-5648 http://arose.iweb.bsu.edu
M.A. Rose 2008 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