UCLA Engineers Develop Polymer Solar Energy Cells

October 09, 2005 by Jeff Shepard

UCLA Henry Samueli School of Engineering and Applied Science (Los Angeles, CA) have developed a new and affordable way to harness the power of the sun using solar cell panels made out of everyday plastics. UCLA engineering professor Yang Yang, postdoctoral researcher Gang Li, and graduate student Vishal Shrotriya have created a new plastic (or polymer) solar cell they hope eventually can be produced at a mere 10 percent to 20 percent of the current cost of traditional cells, making the technology more widely available.

Currently, almost 90 percent of the solar cells in the world market are made from a refined, highly purified form of silicon -- the same material used in manufacturing integrated circuits and computer chips. High demand from the computer industry has reduced the availability of quality silicon, resulting in high costs that rule out solar energy as an option for the average consumer. Made of a single layer of plastic sandwiched between two conductive electrodes, UCLA's solar cell is easy to mass-produce and costs much less to make -- roughly one-third of the cost of traditional silicon solar technology. The polymers used in its construction are commercially available in large quantities.

Independent tests on the UCLA solar cell already have received high marks. The National Renewable Energy Laboratory (NREL, Golden, CO), a certification organization for solar technology, has helped the UCLA team ensure the accuracy of its efficiency numbers. The efficiency of the cell is the percentage of energy the solar cell gathers from the total amount of energy, or sunshine, that actually hits it. According to the UCLA team, the 4.4-percent efficiency achieved is the highest number yet published for plastic solar cells. Given the strides already made with the technology, the UCLA team calculates that they will be able to double the efficiency percentage in a short period of time. The target for polymer solar cell performance is ultimately about 15 percent to 20 percent efficiency, with a 15-year to 20-year lifespan. Large-sized silicon modules with the same lifespan typically have a 14 percent to 18 percent efficiency rating. The plastic solar cell is still a few years away from being available to consumers, but the UCLA team is working diligently to get it to market.

"Solar energy is a clean alternative energy source. It's clear, given the current energy crisis, that we need to embrace new sources of renewable energy that are good for our planet. I believe very strongly in using technology to provide affordable options that all consumers can put into practice," said Yang. "We hope that ultimately solar energy can be extensively used in the commercial sector as well as the private sector. Imagine solar cells installed in cars to absorb solar energy to replace the traditional use of diesel and gas. Using the same principle, cell phones can also be charged by solar energy. There are such a wide variety of applications."