New answers tagged photovoltaics
I guess the question is whether the LED will also act as a photodiode, i.e. whether incident light will excite electrons and therefore generate a current. If so, then reflect the diodes light back onto it will indeed reduce the current flowing in the diode by generating an opposing EMF. This turns out to be surprisingly hard to Google, but Wikipedia ...
Rare earth elements aren't really used much in PV at all. The market is dominated by silicon cells (~95% of the market). The next big player is Cadmium Telluride (~5% of the market). The rest are pretty insignificant. Also, note that rare-earth elements are (with the exception of Promethium) not particularly rare.
The major one is Indium. Indium Tin Oxide is used as a transparent conductive electrode used to coat the top of the cell. Indium production is a potential bottleneck when it comes to expansion of the PV manufacturing industry and currently costs around $700/kg. Less than 1000 tonnes per year is produced. However, it looks like it may well be replaced with ...
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