Photovoltaic Effect: Electron Movement & Mass Change

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    Photovoltaic
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Discussion Overview

The discussion centers around the photovoltaic effect, specifically focusing on the movement of electrons in photovoltaic cells and whether this movement affects the mass of the cells. Participants explore the underlying physics, including the role of excited electrons and potential differences in photovoltaic systems.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • Some participants propose that photons excite electrons to a conduction band, allowing them to create electric current.
  • Others question the extent of electron movement in photovoltaic cells, comparing it to electron movement in typical conductors.
  • A participant emphasizes the importance of potential difference in photovoltaic cells, suggesting that simply placing electrons in the conduction band does not account for the cell's functionality.
  • There is a mention of the mean free path of electrons in metals versus semiconductors, with a claim that electrons in semiconductors may have a longer mean free path due to lower scattering rates.
  • One participant requests resources for further study on photovoltaic physics.
  • Another participant recommends a specific book on semiconductor physics.

Areas of Agreement / Disagreement

Participants express differing views on the implications of electron movement and the role of potential difference in photovoltaic cells. The discussion remains unresolved regarding the specific questions raised about electron movement and mass change.

Contextual Notes

Participants do not fully agree on the implications of electron movement in photovoltaic cells, and there are unresolved questions about the relationship between electron excitation and mass change in the cells.

Who May Find This Useful

Individuals interested in the physics of photovoltaic cells, semiconductor devices, and the underlying principles of electron movement in materials may find this discussion relevant.

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

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