Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Solar Cells -- Faissal's Presentation to Dorsinville Group and Guests, on Friday 8th October 2010

1,836 views

Published on

Solar Cells -- Faissal's Presentation to Dorsinville Group and guests, on Friday 8th October 2010

  • Be the first to comment

Solar Cells -- Faissal's Presentation to Dorsinville Group and Guests, on Friday 8th October 2010

  1. 1. Solar Cells Quantum Dot Enhanced SWCNT-Polymeric Solar Cells M. Faisal Halim Prof. Dorsinville, Walser, Hovhannisyan
  2. 2. What is a Solar Cell? <ul><li>A devices that generates electricity using light. </li></ul><ul><li>A Photovoltaic device generates a voltage when illuminated. </li></ul>Source: http://staff.science.nus.edu.sg/~chmxqh/research.html 8th October, 2010
  3. 3. Why Solar Cells? <ul><li>Tremendous potential for generating electricity </li></ul><ul><li>Government thrust: Green economy initiatives </li></ul><ul><li>Market forces: Other fuel sources are scarce resources </li></ul>
  4. 4. Current Solar Cells use Crystalline Technology <ul><li>Disadvantages of Crystalline Technology </li></ul><ul><li>Crystals need to be grown – expensive process </li></ul><ul><li>Lack of flexibility </li></ul><ul><li>Polycrystalline cells lack efficiency </li></ul><ul><li>Challenges in fabrication </li></ul>
  5. 5. Nanocrystal-Polymer Hybrid Solar Cells <ul><li>Advantages </li></ul><ul><li>Cheap </li></ul><ul><li>Mechanically Flexible </li></ul><ul><li>High Efficiency </li></ul><ul><li>Solution Processible </li></ul><ul><ul><li>Can take Advantage of Molecular Self Assembly </li></ul></ul><ul><ul><li>Processes are highly scalable </li></ul></ul><ul><li>Ease of Fabrication </li></ul><ul><li>Low Toxicity of Processing Methods </li></ul>
  6. 6. Basic Solar Cell Architecture Source: http://staff.science.nus.edu.sg/~chmxqh/research.html 8th October, 2010 Source: Solar Energy Materials and Solar Cells Volume 87, Issues 1-4, May 2005, Pages 733-746 Photo Active Layer:
  7. 7. <ul><li>Absorbs light and produces an electric voltage. </li></ul><ul><li>Quantum Dots (QD) absorb light </li></ul><ul><li>Carbon Nanotubes (SWCNT): conduct electrons from QD to cathode </li></ul><ul><li>P-type polymer (P3OT) conducts holes to anode </li></ul><ul><li>Area of interest </li></ul>Photo Active Layer Source: Solar Energy Materials and Solar Cells Volume 87, Issues 1-4, May 2005, Pages 733-746
  8. 8. Tasks Involved <ul><li>Material Synthesis </li></ul><ul><ul><li>Synthesis </li></ul></ul><ul><ul><li>Characterization: ABS, PL, Z-Scan </li></ul></ul><ul><li>Deposition of the Active Layer </li></ul><ul><ul><li>Synthesis </li></ul></ul><ul><ul><li>Characterization: ABS, PL, Z-Scan, Film Thickness, Film Surface Morphology, Film Uniformity </li></ul></ul><ul><li>Device Fabrication </li></ul><ul><ul><li>Synthesis </li></ul></ul><ul><ul><li>Characterization: VI Characteristics, Response to Light </li></ul></ul>
  9. 9. Tasks: Material Synthesis <ul><li>Synthesis of CdSe Quantum Dots </li></ul><ul><li>Purification of Single Walled Carbon Nanotubes (SWNT) </li></ul><ul><li>Making Solutions of P3OT Polymer </li></ul><ul><li>Making Solutions of PEDOT:PSS </li></ul><ul><li>Making Appropriate Solution Mixtures </li></ul>
  10. 10. Tasks: Deposition of Active Layer <ul><li>Appropriate Solution Mixtures Spin Coated. Films are of: </li></ul><ul><ul><li>Optical Quality </li></ul></ul><ul><ul><li>Uniform Thickness </li></ul></ul><ul><ul><li>Uniform Composition </li></ul></ul><ul><li>Films Grown Layer by Layer </li></ul><ul><ul><li>Deposition at 80 RPM </li></ul></ul><ul><ul><li>Coating, 10 secs, 1000 RPM </li></ul></ul><ul><ul><li>Drying, 200 RPM </li></ul></ul><ul><li>Films of Different Materials Deposited Sequentially </li></ul>
  11. 11. Tasks: Device Fabrication <ul><li>Spin Coating PEDOT:PSS onto ITO Coated Substrate </li></ul><ul><li>Spin Coating Active Layer Material </li></ul><ul><li>Vapor Depositing Al electrodes </li></ul>
  12. 12. CdSe Quantum Dot Synthesis <ul><li>CdSe QD Preparation 55 degrees Celcius Relatively Low Toxicity Materials: </li></ul><ul><li>Add Decylamine to Aqueous CdNTA </li></ul><ul><li>Add Aqueous Na 2 SeSO 3 </li></ul><ul><li>Add Toluene </li></ul><ul><li>CdSe QDs Migrate to the Toluene Phase </li></ul><ul><li>Add a Polymer Solution to Preserve QDs </li></ul>Source: Published online: 25 January 2004; doi:10.1038/nmat1056 Absorption Spectrum of CdSe QDs (aq)
  13. 13. Carbon Nanotube Purification <ul><li>Carbon Nanatubes Purchased in Impure Form. Purification Removes: </li></ul><ul><ul><li>Soot ( 470 o C in Oven, in Air ) </li></ul></ul><ul><ul><li>Metal Catalyst (Sonicating in HCl) </li></ul></ul><ul><ul><li>HCl (Sonicating and Centrifuging in DI Water) </li></ul></ul>Absorption Spectrum of SWCNTs (aq)
  14. 14. Active Layer Film <ul><li>Optical Quality </li></ul><ul><li>Uniform Thickness </li></ul><ul><li>Homogeneous </li></ul>Absorption Spectrum of 6 Layer Film of SWCNT in P3OT
  15. 15. Z-Scan Characterization <ul><li>Open Aperture </li></ul><ul><ul><li>Measures Multi-Photon Absorption </li></ul></ul><ul><ul><li>Measures Saturable Absorption </li></ul></ul><ul><li>Closed Aperture </li></ul><ul><ul><li>Measures Refractive Index as a Function of Intensity </li></ul></ul><ul><ul><li>Can be used as a measure of Optical Activity </li></ul></ul>
  16. 16. What the Measurements Will Tell Us <ul><li>Absorption Spectra </li></ul><ul><ul><li>Exciton Peak Wavelength </li></ul></ul><ul><li>Fluorescence Spectra </li></ul><ul><ul><li>Quantum Dot Size </li></ul></ul><ul><ul><li>Quantum Dot Surface Roughness </li></ul></ul><ul><li>Open Aperture Z-Scan </li></ul><ul><ul><li>Evidence of Excitation of Charge Carriers </li></ul></ul><ul><li>Closed Aperture Z-Scan </li></ul><ul><ul><li>Optical Response of Material in Resonant and Non-Resonant Wavelength Regimes </li></ul></ul>
  17. 17. How We May Use The Experimental Data <ul><li>The data will influence how and what parameters in the solar cells we optimize: </li></ul><ul><li>Surfactant, for: </li></ul><ul><ul><li>QD Surface Passivation </li></ul></ul><ul><ul><li>QD Shape </li></ul></ul><ul><ul><li>QD Size </li></ul></ul><ul><ul><li>QD’s Electrical Contact with Carbon Nanotubes </li></ul></ul><ul><ul><li>QD Surface roughness </li></ul></ul><ul><li>Carbon Nanotube, for: </li></ul><ul><ul><li>Diameter </li></ul></ul><ul><li>Polymer, for: </li></ul><ul><ul><li>Chain Length </li></ul></ul><ul><ul><li>Number of Side Chains </li></ul></ul><ul><ul><li>Functional Groups </li></ul></ul><ul><ul><li>Conductivity </li></ul></ul>
  18. 18. Other Experiments <ul><li>Third Order Nonlinear measurements performed for novel polymers </li></ul><ul><li>Possible Application in all-optical switching </li></ul><ul><li>Collaborative project with Professor Ogawa, Universidad Nacional Autónoma de México </li></ul>Source: Dyes and Pigments Volume 88, Issue 2, February 2011, Pages 129-134
  19. 19. Questions? <ul><li>End </li></ul>

×