High temperature Superconductors and solar panels

Discussion in 'General Science & Technology' started by ajanta, May 14, 2016.

  1. ajanta Registered Senior Member

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    611
    • Post edited for off-topic quotes without citations, links or non-original content indicators.
    Low temperature p-type semiconductor:

    [Moderator: QUOTE DELETED. How is this so hard? You cut-and-pasted the entire abstract to
    D. D. Edwall, E. R. Gertner, and W. E. Tennant, “Variable temperature hall effect on \(\textrm{p-Hg}_{1−x}\textrm{Cd}_{x}\textrm{Te}\) grown on CdTe and sapphire substrates by liquid phase epitaxyJournal of Electronic Materials, 14 (3) , pp 245–268 (1985)
    without linking or indicating the source of your material or serious discussion of your copypasta.]

    [Moderator: Taken from the third paragraph of the History section of “High-temperature superconductivity” I have surrounded your copied material with quote indicators so people won't mistake it for your original writing.]

    (from wiki) [Moderator: Wikipedia is huge, so specific citations are needed. Clearly marked links are better. Taken from the first paragraph of the Iron-based Superconductors section of “High-temperature superconductivity” I have again surrounded your copied material with quote indicators. ]

    So can superconductor be donor as n-type to low temperature p-type semiconductor for solar panels of high efficiency on cold planet or natural satellites ? Thanks
     
    Last edited by a moderator: May 17, 2016
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  3. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    I don't think you undersatand why silicon based PV cell is limited to about 23% conversion efficiency (looking at our sun).

    A photon with energy equal to the band gap can be converted with 100% efficiency. I. e. just lift an electron from the top of the populated conduction band accross the band gap to the bottom of the basically unpopulated valence band.

    If the photon has more than that energy, the electron will be lifted into a higher state of the valance band, and rapidly drop down to the bottom. The excess energy it had over the band gap energy is converted into heat as it cascades down.

    A photon with less than the band gap can not do anything useful. It just makes heat as it induces collision among electrons of the conduction band.

    The solar spectrum of photon energies is not as well matched to the band gap as that of a cooler star .

    I did not follow your discussion of various semi-conductors as I believe it is all irrelevant for PV cells, unless you are creating a slightly larger band gap better matched to our sun.
     
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  5. ajanta Registered Senior Member

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    Haa...haa...! Yes, you are correct, I don't undersatand why silicon/others based PV cell is limited to about .....% conversion efficiency (looking at our sun). I knew that it's about band gap but not as well. Thanks for your important description.

    So larger band gap(p-type) better matched to light with superconductor as n-type(if it is possible) can be better efficient PV cell at low temperature(matched) ?
     
    Last edited: May 14, 2016
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  7. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    I has been at least four decades since I knew more than a little solid state physics; but I as recall, the n or p dopping only changes the Fremi level with in the band gap, not the band gap width.

    When two differently dopped semiconductors are physically connected, they adjust so that the Fermi levels are the same. The one with the higher Fermi level (when separated) has higher energy electrons and with contact, some will flow into the other to make this the case.
     
    Last edited: May 14, 2016
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