1. Project #4: Renewable Energy System: Dyeing to Create Solar Power Introduction Since the industrial revolution, humans have depended primarily on fossil fuels for low cost energy. With continued wide-spread use, however, their environmental effects and depleted supply has renewed interest in finding alternative renewable sources of energy. Solar technology is a viable alternative energy source because it is widely available, free, and tested technology. Current solar technologies are not very efficient so it is important to understand under which circumstances the most energy will be able to be created Introduction Since the industrial revolution, humans have depended primarily on fossil fuels for low cost energy. With continued wide-spread use, however, their environmental effects and depleted supply has renewed interest in finding alternative renewable sources of energy. Solar technology is a viable alternative energy source because it is widely available, free, and tested technology. Current solar technologies are not very efficient so it is important to understand under which circumstances the most energy will be able to be created Objective Currently, using synthetic dyes are the best method to create most efficient fuel cells. Our goal is to find a cost effective natural dye that has a level of efficiency that is close to or exceeds that of it’s synthetic counterpart. Objective Currently, using synthetic dyes are the best method to create most efficient fuel cells. Our goal is to find a cost effective natural dye that has a level of efficiency that is close to or exceeds that of it’s synthetic counterpart. Conclusion Nanocrystalline solar cells are a cost effective way to generate electricity from the sun. Further research, however, needs to be done to improve their efficiency. Using spinach leaves to dye the solar cells, proved to be just as efficient as using the more expensive synthetic dye. The efficiency of the spinach-dyed cells was much higher then using a blackberry dye. Our results show spinach to be a good replacement for the blackberry organic dye and may prove to be even more effective with more research. Conclusion Nanocrystalline solar cells are a cost effective way to generate electricity from the sun. Further research, however, needs to be done to improve their efficiency. Using spinach leaves to dye the solar cells, proved to be just as efficient as using the more expensive synthetic dye. The efficiency of the spinach-dyed cells was much higher then using a blackberry dye. Our results show spinach to be a good replacement for the blackberry organic dye and may prove to be even more effective with more research. Stephanie Baldwin, Little Miami Junior High School, Morrow, Ohio Deon Edwards, Western Hills Engineering High School, Cincinnati, Ohio Method for Creating Solar Cells Testing and Data The testing was completed using a solar simulator collecting data to find the short circuit current and open circuit voltage for our dyed solar cells. These point are obtained by find the y and x intercept, respectively, for each set of data. The maximum power was also found by finding the highest power density value between the short circuit current and open circuit voltage. By comparing the max power values with the sun’s typical output of approximately 80-100 mW/cm 2, the cell efficiency was calculated. Testing and Data The testing was completed using a solar simulator collecting data to find the short circuit current and open circuit voltage for our dyed solar cells. These point are obtained by find the y and x intercept, respectively, for each set of data. The maximum power was also found by finding the highest power density value between the short circuit current and open circuit voltage. By comparing the max power values with the sun’s typical output of approximately 80-100 mW/cm 2, the cell efficiency was calculated. Acknowledgements We would like to acknowledge Dr. Shanov, Feng Wang, Anant Kukreti, Andrea Burrow, all of our fellow RET teachers, and everyone who supported our research. We also offer our sincere thanks to the NSF for their grant support the Research Experience for Teacher program. Acknowledgements We would like to acknowledge Dr. Shanov, Feng Wang, Anant Kukreti, Andrea Burrow, all of our fellow RET teachers, and everyone who supported our research. We also offer our sincere thanks to the NSF for their grant support the Research Experience for Teacher program. Grant #ECC0808696 Step 1: Using conductive glass plates, we spread a layer of TiO2 suspension on each plate. Step 2: The suspension dried on to the plates in a 450 degree oven heated for 30 minutes. Step 3: Spinach or blackberries were ground to create dye, then pulled out the dye using a filtered strainer. The synthetic dye was prepared earlier. Step 4: The coated plates were placed face down in the each dye and let them soak overnight. Step 5: A layer of carbon was applied to the conductive side of more plates with a carbon pencil. Step 6: Plates were removed from the dyes, given a methanol rinse and allowed to dry. Step 7: Cells were assembled by placing a dyed plate on top of a carbon coated plate in a staggered position. Plates are held together using two small binder clips. Step 8: Drops of iodine were placed along the edge of the combined plates as a catalyst. Step 9: Assembled solar cells were ready for efficiency testing. TiO 2 Coating with Spinach Dye Electrolyte (Iodine) Carbon Layer (use for catalyst) How Dye Sensitized Solar Cells work: 1.Sunlight enters the cell striking the dye in the TiO 2 coating the electrode glass. Photons striking the dye create an excited state releasing an electron. 2.The electron exits through the conductive layer of the electrode plate. 3.After doing work, the electrons return back to the cell through the counter electrode. The returning electron combines with the electrolyte. 4.The electrolyte then returns an electron back to the dye coating readying the cell for the next photon strike. How Dye Sensitized Solar Cells work: 1.Sunlight enters the cell striking the dye in the TiO 2 coating the electrode glass. Photons striking the dye create an excited state releasing an electron. 2.The electron exits through the conductive layer of the electrode plate. 3.After doing work, the electrons return back to the cell through the counter electrode. The returning electron combines with the electrolyte. 4.The electrolyte then returns an electron back to the dye coating readying the cell for the next photon strike. Counter Electrode Glass plate Electrode Glass plate 1 1 2 2 3 3 4 4 Results When you look at the view the short circuit and open circuit voltage (in table above) you notice that the current values for the blackberry and spinach are both on a lower level than the synthetic cells. The real difference is uncovered once you find the compare the max power and the cell efficiency. You notice the efficiency of our best spinach cell slightly exceeded the level of our best synthetic cell. Although the power levels are extremely low compared to silicon based or other current technology, more research could lead to more productive spinach dye cells. Results When you look at the view the short circuit and open circuit voltage (in table above) you notice that the current values for the blackberry and spinach are both on a lower level than the synthetic cells. The real difference is uncovered once you find the compare the max power and the cell efficiency. You notice the efficiency of our best spinach cell slightly exceeded the level of our best synthetic cell. Although the power levels are extremely low compared to silicon based or other current technology, more research could lead to more productive spinach dye cells. Dye TypeMaximum Power Cell Efficiency Range Synthetic.0299 mW/cm 2.029% to.037% Blackberry.0029 mW/cm 2.003% to.004% Spinach.0317 mW/cm 2.031% to.039% Dye TypeShort Circuit Current Open Circuit Voltage Synthetic.55 mA/cm 2 215 mV Blackberry.27 mA/cm 2 45 mV Spinach.30 mA/cm 2 305 mV