Energy and Nanotechnology Issues and Opportunities in Photovoltaics

1. Energy and Nanotechnology Issues and Opportunities in Photovoltaics S. Ismat Shah Physics and Astronomy Materials Science and Engineering Senior Policy Fellow Center for Energy and Environment Policy University of Delaware ICNMRE, Al Maghrib, 2010

3. Richard Smalley (1943 -2005) Nobel Prize in Chemistry (1996)

4. Top Ten Global Concerns

5. Top Ten Global Concerns 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Population

6. Top Ten Global Concerns 1. 2. 3. 4. 5. 6. 7. 8. 9. Democracy 10. Population

7. Top Ten Global Concerns 1. 2. 3. 4. 5. 6. 7. 8. Education 9. Democracy 10. Population

8. Top Ten Global Concerns 1. 2. 3. 4. 5. 6. 7. Disease 8. Education 9. Democracy 10. Population

9. Top Ten Global Concerns 1. 2. 3. 4. 5. 6. Terrorism and War 7. Disease 8. Education 9. Democracy 10. Population

10. Top Ten Global Concerns 1. 2. 3. 4. 5. Poverty 6. Terrorism and War 7. Disease 8. Education 9. Democracy 10. Population

11. Top Ten Global Concerns 1. 2. 3. 4. Environment 5. Poverty 6. Terrorism and War 7. Disease 8. Education 9. Democracy 10. Population

12. Top Ten Global Concerns 1. 2. 3. Food 4. Environment 5. Poverty 6. Terrorism and War 7. Disease 8. Education 9. Democracy 10. Population

13. Top Ten Global Concerns 1. 2. Water 3. Food 4. Environment 5. Poverty 6. Terrorism and War 7. Disease 8. Education 9. Democracy 10. Population

14. Top Ten Global Concerns 1. Energy 2. Water 3. Food 4. Environment 5. Poverty 6. Terrorism and War 7. Disease 8. Education 9. Democracy 10. Population

18. And we produce 90 million barrels of oil per day right now…….

20. The Global Picture Maroc Founded Fossil Fuel Derived Energy

21. There is no explicit solution! -There is very little hope in new technologies but they have to be pursued because there is no other option. (look for regional solutions) -The only partial solution comes from increased efficiencies, new materials and designs, and most importantly,……..

22. There is no explicit solution! -There is very little hope in new technology but they have to be pursued because there is no other option. (look for regional solutions) - The only partial solution comes from increased efficiencies, new materials and designs, and most importantly reduction in consumption.

23. Radiant Facts Diameter: About 100 times that of earth Mass: 99.8% of the Solar System (Jupiter has most of the rest) Core Temperature: 15.6 x 106 K Surface Temperature: 5800K Energy Production: 386 billion billion megawatts Insolation: 1000 - 250 Watts per square meter Age: 4.5 billion Years (5 billion years more to go)

24. Nanotechnology and Photovoltaics

28. PV Production

29. Case of Maroc IEA UNO

30. Total Consumption

31. Total Crude Oil Production

32. Proven Reserves

33. World Energy Production BP 2006 statistical review

34. Current PV Status • 2008: Global PV production 7 GW • 2008: Cumulative installed PV electricity generation capacity in the world was around 15 GW, with Europe accounting for more than 60% of this (9.5 GW) • China as the new leading producer of solar cells, with an annual production of about 2.4 GW, followed by Europe with 1.9 GW, Japan with 1.2 GW and Taiwan with 0.8 GW. (Where is USA?)

35. Hashimoto Predictions

36. Hashimoto Solution

37. The Disconnect 1. Materials Issues 2. Device Issues 3. Not a chance!

39. Nate Lewis (CIT) calculations

40. How does the area required changes with high efficiency solar cells?

41. How does the area required changes with high efficiency solar cells? • 20 TWatt model • With 10% cells, we needed 5 x 1011 square meters of solar cells. • With 50% cells, we will still need about 1011 square meters of solar cells. • We currently produce about 1 million sq. meters of solar panels. • We need to increase production by 5 orders of magnitude.

42. How much material do we need? • For 1 x 1011m2, we will need (1011 x 104 x 0.01 cm3)/(2.33 g/cm3) = 5 x 109 Kg of Silicon

43. How much material do we need? • For 1 x 1011m2, we will need (1011 x 104 x 0.01 cm3)/(2.33 g/cm3) = 5 x 109 kg of Silicon Each kg of Si requires 15 kg of carbon to produce electronic grade Si. To obtain a kg of refined grade of (poly)Si, we use up about 200 kWh of energy emitting 40 kg of CO2, using 1000 gallons of water. (Availability, Toxicity)

44. Device Issues

45. Shockley-Queisser Limit • Three types of losses are described: • Sub-band radiation • Radiative recombination • Thermalization

46. Sub-band Radiation hn < Eg Eg Non-absorbance of photons with energy below the bandgap energy

47. Radiative Recombination • Second Loss Mechanism: Radiative recombination, the inverse of photovoltaic electron-hole pair generation process. • It is a fundamental loss-mechanism that is always present at any non-zero cell temperature.

48. Radiative Recombination Recombination of electrons and holes generated by (a) optical absorption and (b) a forward- biased p-n junction.

49. Shockley-Queisser Limit • The third mechanism for a PV cell using single semiconductor material is thermalization of electron-hole pairs generated by photons with energy above the band-gap (Eg) energy.

50. Loss Mechanisms