Shares of First Solar ( FSLR) were lower by 6.8% Monday following a report in Barron's that cheaper silicon will hurt the Phoenix-based company's competitive advantage.

First Solar was down $9.96 to $137.40. Barron's said that a main selling point of panels sold by First Solar and Energy Conversion Devices ( ENER) was that they used little silicon, and hence were cheaper than traditional panels. Energy Conversion was down almost 13%, or $2.03, to $13.74.

Bill Alpert wrote in Barron's Monday that: "A key selling point of thin-film panels is their reduced use of costly materials like silicon: a 97% reduction, in most thin-film technologies. Now that silicon is cheaper, First Solar is hustling around to investor conferences explaining how it aims to fly under silicon's descending cloud ceiling."

Solar stocks got a boost last week following a report in DigiTimes that the Chinese government would provide more support for its solar industry.

Most of those companies were giving back gains today. JA Solar ( JASO) shares were lower by 14.2%, or 56 cents to $3.37.

Solar Fun Power ( SOLF) was down 10.5%, or 49 cents to $4.18.

Suntech Power ( STP) was down 8.8%, or $1.02, to $10.63.

LDK Solar ( LDK) was down 8.9%, or 60 cents to $6.55.

Green Plains Renewable Energy ( GPRE), based in Omaha, Neb., was a bright spot as its shares were higher by 1% to $3.

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