Two of the biggest challenges to solar power are cost and efficiency, though scientists at Empa, the Swiss Federal Laboratories for Materials Science and Technology, took another small step towards conquering both obstacles. Less than a week ago, an independent laboratory confirmed that Empa surpassed the previous world record (which it also held), for energy conversion efficiency on flexible polymer foils. By modifying the semiconducting material responsible for absorbing light, the team of scientists was able to convert 20.4 percent of sunlight into electricity—far surpassing the previous record of 18.7 percent.
It is equally significant that the solar cells, which lie on flexible polymer substrates, are relatively cheap and easy to produce. The roll-to-roll manufacturing process, which “prints” electronic devices onto flexible material, will likely play a critical role in reducing the cost of flexible solar panels. Empa director, Gian-Luca Bona, is collaborating with Flisom, an industrial thin films producer, to begin cost-efficient production.
In addition to the likely possibility of slashing manufacturing costs, the malleability and light weight of flexible solar cells make them ideal for various applications. Examples include solar farms, vehicles, portable electronics, military equipment, and architectural integration such a building facades and roof shingles.
Empa scientists, led by Ayodhya Tiwari, have boosted the efficiency of flexible CIGS solar cells since 1999, when it set the record at 12.8 percent. The latest record of 20.4 percent is significant because it surpasses the 20.3 percent efficiency value of CIGS solar cells on (non-flexible) glass substrates, and matches the efficiency rate for polycrystalline silicon wafer-based solar cells.
But before you grab your checkbook, there are a couple things to consider. As Kevin Bullis points out, there will likely be some variability between the published lab results and the real world, sometimes as great as 30 percent. The new record is also specific to the materials used in the solar panels and lags behind top-shelf leaders by a wide margin. Still, the latest flexible solar cell by Empa is promising because it offers relatively high efficiency with the promise of reducing manufacturing costs.
Image by Empa
