Ars Technica: Two research groups at IBM are working on different ways to help lower the price of solar technology to $2 per watt, the price needed for solar to be competitive with fossil fuels. Most current solar panels use silicon-based photovoltaic chips; however, silicon is relatively expensive. One of the groups at IBM is attempting to replace silicon with thin films, elemental crystalline layers that are less efficient but much cheaper than silicon. Using a combination of cadmium, zinc, tin, and selenium, the researchers have attained an 11% efficiency, but they need to reach at least 15% to make the panels marketable. The other group is working with photovoltaic chips that are both more efficient and more expensive than silicon. That group is attempting to overcome the cost by using lenses to focus sunlight onto smaller chips. However, the focused sunlight greatly increases the temperatures on the chips, causing them to degrade more quickly. The two teams believe that their approaches will be suited for different environments, with the thin films being more useful in areas with less direct sunlight, and the concentrating photovoltaics more useful in desert-like environments.