An oversupply of solar cells? That's what an analyst writing on Seeking Alpha says is happening. Part of his argument:
.......if thin film solar continues at its same growth rate, in 2009 thin film will make up 17.8% of all solar power generation. That would leave a capacity of polysilicon exceeding demand by 17,000 metric tons, based on capacity expansions announced by the polysilicon manufacturers.
He is basically saying it might not be a great time to buy stock in solar cell companies, which might be about to see a contraction in profit margins. The comments posted at the end of the piece are interesting as well.
http://seekingalpha.com/article/67253-contradictions-in-the-solar-market