Shaun Pacheco

Table of Contents

First Presentation

Questions from the first presentation

  1. Why is silicon used to make solar cells? Does it have the lowest work function?
  2. What loss is associated with inverters and battery storage? Is this a place to look for improvements?
  3. I didn't follow the discussion of the basic physics. Could you explain the energy gap, pn-junction, and work function more carefully?
  4. Why are PVs connected in series, not in parallel?
  5. What are recent developments in PV research that could increase cell or module efficiency?
  6. What losses are associated with transferring the current in solar cells?
  7. Does constant photon bombardment degrade the solar cell material over time?
  8. What is the most efficient band gap for a single-junction cell absorbing sunlight?
  9. Assuming costs and efficiency are at decent levels, how feasible would it be to get PV cells on a majority of American roofs?
  10. Are government subsidies of PV fair? Should they have a sunset?
  11. How does the temperature of the solar cell affect efficiency?
  12. How long does it take a solar cell to reach the energy break-even point (when it has generated as much energy as was required to produce it)?
  13. How rapidly is solar PV production growing? What is the trend on cost per installed watt?

Second Presentation

Some additional questions

  1. How rapidly has the cost per watt of solar photovoltaics declined in recent decades?
  2. Are CdTe thin-film cells cheaper to manufacture than silicon cells? Why?
  3. What are the prospects for concentrated PV using multijunction cells? Are there conditions where this approach makes more sense?
  4. What are dye-sensitized solar cells? The Graetzel cell?
  5. Roughly speaking, the cost of solar PV breaks down into three parts: manufacturing the cells, assembling the modules, and installing the panels. There are additional wiring and inverter costs, too. How do these costs compare?
  6. How rapidly is the world’s capacity to produce PV growing? China’s? America’s?
  7. What is the theoretical limit of PV efficiency? How closely are we likely to approach this limit?
  8. Would it be better to figure out how to make low-efficiency PV cheaply than trying to produce more expensive, more efficient cells?

~Peter Saeta 2010 March 10 at 10:16 PM PST

  • (is this where the second presentation questions go?) Q: So the conductivity of a material is highly sensitive to the band gap, the difference in energy between the valence and conducting energy bands -- does the Earth's magnetic field split the energy levels in either the valence or conducting bands via the Zeeman effect in such a way as to reduce the resistivity of the solar cell material and increase efficiency? Can magnets be efficaciously used to produce such an effect? ( the Zeeman effect is kind of wimpy so I don't think so . . .)
  • How exactly do solar panels work?
  • What are the major factors contributing to the efficiency of solar panels?
  • What are the different types of solar panels (ie multijunction cells, concentrators, thin film, silicon, nano-wire arrays, plasmonic photovoltaics) , and what are the advantages and disadvantages of each?
  • How much efficiency is lost on a cloudy day?
  • How can we store the energy from solar panels? What are the most efficient methods of storage?
  • Is there some way to convert the energy from the solar panel into a liquid fuel?
  • How are solar panels currently being used? How much energy are they collecting?
  • What are the limits in solar panels technology? Will we ever run out of materials needed to make solar panels? What limits the efficiency? Will we run out of land to store solar panels?
  • How long does it take to get the money back after buying the solar panels?


  1. "Solar Cell Efficiency Tables (Version 33)." Wiley InterScience. N.p., n.d. Web. 30 Mar. 2010. < >.
  2. Andreev, V. M., V. A. Grilikhes, and V. D. Rumyantev. Photovoltaic Conversion of Concentrated Sunlight. New York, NY: Wiley, 1997. Print. Honnold Mudd Call No. TJ812 .A513 1997
  3. Biello, David . "New Solar Cell Efficiency." Scientific American. N.p., n.d. Web. 30 Mar. 2010. < >.
  4. Handbook of Photovoltaic Science and Engineering. New York, NY: Wiley, 2003. Print.
  5. Kirchartz, and Thomas. "Generalized detailed balance theory ... - Google Books." Google Books. N.p., n.d. Web. 31 Mar. 2010. <>
  6. Kreith, Frank, and Jan F. Kreider. Principles of Solar Engineering. Washington: Hemisphere Publishing Corp, 1978. Honnold Mudd Call No. TJ 810 K73
  7. Record Makes Thin-Film Solar Cell Competitive with Silicon Efficiency." National Renewable Energy Laboratory. N.p., n.d. Web. 30 Mar. 2010. < >.
  8. Solar Cells and Their Applications (Wiley Series in Microwave and Optical Engineering). New York: Wiley-Interscience, 1995. Print. Honnold Mudd Call No. TK2960 .S652 1995

Useful Links

Timeline of Solar Power

Cost of Solar Installation

Solar cell animation

Performance calculator for grid-connected photovoltaic systems by region. ~Peter Saeta 2010 February 28 at 03:35 PM PST