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P isn't a metal, isn't a heavy element, and isn't toxic except in the form of white phosphorus. It's what holds your DNA together and what your mitochondria us
by kragen 1y ago
P isn't a metal, isn't a heavy element, and isn't toxic except in the form of white phosphorus. It's what holds your DNA together and what your mitochondria use to fuel your cellular respiration. Perhaps coincidentally, it's the only element in your list that is used in practice as dopants for silicon solar cells. The other dopant used in practice, which you omitted, is boron, which also isn't especially toxic, and also isn't a metal or a heavy element.
GaAs photovoltaic cells, InGaAs photovoltaic cells, etc., do exist, but aren't used in utility-scale solar power, because their cost doesn't compensate for their performance. Some of the other elements you list are never used at all for photovoltaic cells to my knowledge.
Wherever you got this information from, you should killfile it and make sure you don't trust any more information from that source.
- pfdietz 1y agoActually, gallium has replaced boron as a dopant for Si PV cells, since it avoids an annoying kind of light-induced efficiency degradation that boron is subject to. I don't believe gallium is significantly toxic, and certainly not at the amounts used as a dopant. The big heavy metal issue for PV has been lead for contact to the backing sheet, but this isn't an issue if you go with bifacial modules (no backing sheet).
- kragen 1y agoI very much appreciate the corrections! Apparently there is one report of gallium poisoning in the medical literature; it was nonfatal but resulted in irreversible cardiomyopathy: https://pubmed.ncbi.nlm.nih.gov/22024274/ https://pubmed.ncbi.nlm.nih.gov/22024274/ https://www.pv-magazine.com/2020/06/13/the-weekend-read-gallium-in-the-fight-against-lid/ https://www.pv-magazine.com/2020/06/13/the-weekend-read-gall... backs you up and also mentions that indium (also nontoxic, as far as anybody knows) has been tried but was not in mass use as of that article. https://www.pv-magazine.com/2022/05/24/gallium-doping-and-solar-cell-degradation/ https://www.pv-magazine.com/2022/05/24/gallium-doping-and-so... talks about the potential of "rejuvenating" gallium-doped PV cells.