Nobel-winner has vision of affordable solar power

A thin plastic film coated with tiny solar cells that looks something like a color transparency would absorb enough energy to provide power, Heeger said, but would cost five to 10 times less than traditional solar power.

"I have solar on my roof, and it is wonderful to wake up in the morning and see the power meter running backwards," Heeger said. "My electric bill averages zero ...but it will require 10 to 12 years of use before I earn back the capital cost. It is like having an S-class Mercedes on my roof."

"The goal is to try to make that capital cost significantly less," he said. "If people could have a payback for installation in two years, then it would be everywhere."

Heeger, a physics professor at the University of California Santa Barbara who won the Nobel Prize for chemistry in 2000, was the speaker for the Princeton Regional Chamber of Commerce's 15th an nual Albert Einstein Memorial Lecture last week at the Woodrow Wil son School of Public and International Affairs at Princeton University.

More than 150 members of the business community, university and public attended his lecture, titled "Turning the Dream of Low Cost Plastic Solar Cells into a Reality."

"We are finally seeing some real momentum in this country for the use of wind, solar, and even wave energy," Heeger said. "The fundamental point here as far as solar is concerned is that we receive on the Earth in one hour enough energy to take care of the needs of the planet for a year. The issue is how to use that, how to convert that into electricity."

Converting sunlight to energy is a three-step process, Heeger said. First a material must absorb the photons emitted by the sun, then a photo induced charge separation must occur, and finally the charges need to be collected at electrodes.

A new class of plastic polymers containing metals can be poured on a surface, where they dry into a thin film. This film can be printed as ink on a thin plastic sheet at a relatively low cost. "The dream is to be able to do something like that," Heeger said. "A kind of functional ink containing plastic solar cells."

The trick is to find a way the cells would emit enough energy to meet power needs. Right now the thin plastic coated film does not produce enough energy to make it viable for solar power, but in the future, Heeger believes it will. Scientists are working to create more advanced polymers that will absorb a broader spectrum of light and produce enough energy for solar power.

"We are trying to increase the efficiency," he said. "The efficiency is critically important ... A new class of polymers has recently emerged and this is coming together ... it is not yet good enough, but we are getting some real tools in our tool box. There is a clear vision of technology that will get us to low cost plastic solar cells."

The implications of such technological advances would be monumental, Heeger said.
"In the hand of a family in India or Africa living off the grid, it will change their lives," he said. "They can have lights at night and watch television."