What is the purity level of silicon used to build commercial solar cells?
This was selected as Best Answer Silicon-based solar cells require about “five 9’s” purity (99.999% pure, or 10 ppm). For comparison, semiconductors require at least eight nine’s purity (99.999999% pure, or 10 ppb). Interestingly, solar manufacturing ends up overpaying because the entire silicon production industry revolves around production of the semiconductor grade product, which is much more expensive. PV manufacturers often buy the rejected semiconductor grade — competing with other PV manufacturers to get it. The industry is ripe for disruptive innovation to produce a “just good enough” grade by some other means to get from metallurgical grade (98%) to five 9’s.
