Photovoltaic Effect: Electron Movement & Mass Change

In summary: However, that is a very thick and dense book. If you are just interested in the physics of photovoltaics, a good book to start with is "Solar Cells: Operating Principles, Technology, and System Applications" by Martin Green.In summary, photons cause electrons to move to an excited state, where they are free to move through the material in the conduction band. This motion creates an electric current in the cell. The distance electrons can move is not very far, similar to a typical electric current. The mass of the photovoltaic cell does not change due to the movement of electrons. A good resource for studying the physics of photovoltaics is the book "Solar Cells: Operating Principles, Technology, and System Applications" by Martin
  • #1
Jane11
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Photons cause electrons to move to excited state.
In excited state in the conduction band, electrons are free to move through the material.
This motion of the electron creates an electric current in the cell.
But how far can electrons move? And because electrons are free to move in photovoltaic
cell ( panel), does it mean that mass of the photovoltaic cell ( panel) changes?
 
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  • #2
Jane11 said:
Photons cause electrons to move to excited state.
In excited state in the conduction band, electrons are free to move through the material.
This motion of the electron creates an electric current in the cell.
But how far can electrons move? And because electrons are free to move in photovoltaic
cell ( panel), does it mean that mass of the photovoltaic cell ( panel) changes?

I am not sure you understand the physics of photovoltaic.

Please note that it isn't just about putting an electron in the conduction band of a semiconductor. That does nothing other than increasing its conductivity. There must be a potential difference being built up, because a "cell" is a battery that is a source of potential difference. This is why a photovoltaic cell usually consists of a pn-junction.

The question of "how far can electrons move" is puzzling, because this is no different than the usual electric current. Do you also wondered how far electrons move in a typical conductor when it is conducting electricity? It is NOT VERY FAR (ref: the Drude model). In fact the mean free path of electrons in a metal is typically LESS than the mean free path of electrons in the conduction band of a semiconductor mainly because the electron-electron scattering rate in a semiconductor is significantly less (there are fewer conduction electrons).

Other than that, I don't understand what you are trying to get at with your question.

Zz.
 
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  • #3
Thanks for answering. Can you please recommend a book/website where I can study more about the physics of photovoltaic ?
 
  • #4
My favorite book about semiconductors is by Simon Sze, called "Physics of Semiconductor Devices".
 

FAQ: Photovoltaic Effect: Electron Movement & Mass Change

What is the photovoltaic effect?

The photovoltaic effect is the phenomenon where a material, typically a semiconductor, converts light energy into electrical energy. This process involves the movement of electrons and a change in mass of the material.

How does the photovoltaic effect work?

The photovoltaic effect works by using a material with a bandgap, which is the energy difference between the valence and conduction bands. When light hits the material, it excites electrons in the valence band, causing them to jump to the conduction band and create a flow of electricity.

What types of materials are commonly used in photovoltaic cells?

Semiconductors, such as silicon, are commonly used in photovoltaic cells due to their ability to convert light energy into electrical energy. Other materials, such as cadmium telluride and copper indium gallium selenide, are also used in certain types of photovoltaic cells.

What factors affect the efficiency of the photovoltaic effect?

The efficiency of the photovoltaic effect is affected by several factors, including the material used, the intensity and wavelength of the light, and the temperature of the cell. A higher bandgap and lower temperature generally lead to higher efficiency.

What are the applications of the photovoltaic effect?

The photovoltaic effect has many applications, the most common being in solar panels to generate electricity. It is also used in calculators, watches, and other small electronic devices. In addition, it has potential applications in powering larger systems, such as homes and buildings, and in renewable energy sources.

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