Building a solar cell - semiconductors

In summary, the conversation discusses designing a solar cell to absorb solar light from a 5800K blackbody source. The peak wavelength is around 500 nm, and the minimum and maximum are around 250 nm and 1800 nm, respectively. To make electrons jump into the conducting band, a semiconductor with a bandgap less than 2.48 eV is needed, while for the other extremes of the blackbody radiation, a semiconductor with a bandgap less than 4.96 eV or 0.68 eV is sufficient. The ordering of the layers should be considered based on the length of the solar spectrum and which wavelengths travel further through materials.
  • #1
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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  • #2
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.
 

What is a solar cell?

A solar cell is a device that converts sunlight into electricity. It is typically made of a semiconductor material, such as silicon, which can absorb photons from sunlight and release electrons, creating an electric current.

What are semiconductors?

Semiconductors are materials that have properties in between those of conductors and insulators. They have the ability to conduct electricity, but their conductivity can be controlled by various factors such as temperature or impurities. This makes them ideal for use in solar cells as they can be manipulated to efficiently convert sunlight into electricity.

How do solar cells work?

Solar cells work by absorbing photons from sunlight, which excite electrons in the semiconductor material, allowing them to flow and create an electric current. This current can then be harnessed for various applications, such as powering homes or charging electronic devices.

What are the main types of semiconductors used in solar cells?

The two main types of semiconductors used in solar cells are crystalline silicon and thin-film semiconductors. Crystalline silicon is the most commonly used material and can be further divided into monocrystalline and polycrystalline silicon. Thin-film semiconductors, on the other hand, are made of a variety of materials such as cadmium telluride or copper indium gallium selenide.

What are the advantages of using solar cells?

Solar cells have several advantages over traditional sources of energy. They are renewable, clean, and have no emissions, making them environmentally friendly. They also have a long lifespan and require minimal maintenance. Additionally, they can be used in remote areas where access to traditional power sources is limited.

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