Building a solar cell - semiconductors

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SUMMARY

The discussion focuses on designing a solar cell using thin semiconductors with specific bandgaps to optimize light absorption from a blackbody source at 5800K. The relevant bandgaps mentioned are 1.43 eV, 1.14 eV, 1.35 eV, 0.67 eV, 1.75 eV, 2.4 eV, 2.7 eV, 0.42 eV, and 3.37 eV. The optimal arrangement of these semiconductors should prioritize those with bandgaps less than 2.48 eV to effectively capture the peak wavelength of 500 nm. Additionally, the discussion emphasizes the importance of considering the solar spectrum's width when selecting and ordering the semiconductor layers.

PREREQUISITES
  • Understanding of semiconductor bandgap theory
  • Familiarity with blackbody radiation and Wien's Law
  • Knowledge of solar cell design principles
  • Basic concepts of photon energy and wavelength
NEXT STEPS
  • Research the properties of specific semiconductors with bandgaps around 1.4 eV and below
  • Explore the principles of multi-junction solar cells
  • Study the effects of wavelength on material absorption
  • Learn about the optimization of solar cell efficiency through layer arrangement
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Students and professionals in materials science, electrical engineering, and renewable energy sectors, particularly those involved in solar technology and semiconductor applications.

mathman44
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Homework Statement



Design a solar cell, designed to absorb solar light. Treat the sun as a blockbody source of T=5800K.

To design the cell, you may grow 4 very thin semiconductors of the following bandgaps, in eV:

1.43, 1.14, 1.35, 0.67, 1.75, 2.4, 2.7, 0.42, 3.37

Which of these would you use, and in which order would you arrange them and why?

Of the semiconductors, which would you use, in which order would you arrange them, and why?

The Attempt at a Solution



Using wein's law the peak wavelength of the blackbody spectrum at 5800K is around 500 nm, which is 2.48 eV. The minimum is around 250 nm (4.96 eV), and the max is around 1800 nm (0.68 eV).

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So any semiconductor with a bandgap less than 2.48 eV will suffice to make electrons jump into the conducting band, similarily any semiconductor with BG less than 4.96 or 0.68 will suffice for the other extremes of the blackbody radiation.

I'm not sure how to put this together, any hints?
 
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Intuitively do you think longer or shorter wavelengths travel further through materials? Thinking about that might help you with the ordering of the layers.

You are asking the right questions about the width of the solar spectrum and needing to choose a set of band gaps that cover this width effectively.
 

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