Most solar cells made today are planar and require highly processed silicon. The processing of the silicon takes a great deal of energy and money, causing the panels to be quite expensive. Organic solar cells can be made cheaper, but have such inferior efficiency to make the cost benefit disappear. Researchers at Berkeley Lab have created solar cells both cheaper and have comparable efficiency to the 5.4% of standard solar cells. These new cells are actually nanowires consisting of cadmium sulfide with a copper sulfide layer added via solution chemistry. The researchers believe they can increase efficiency by changing the amount of copper sulfide shell material and hope to achieve the ten-percent efficiency needed to be commercially viable.