FPL Helps Recyclable Solar Cells Take Root

The same building blocks nature uses to produce trees are now being used to enhance high-efficiency products such as photovoltaic solar cells.

By producing pilot-scale quantities of cellulosic nanomaterials, the U.S. Forest Service Forest Products Laboratory (FPL) is collaborating with researchers at the Georgia Institute of Technology and Purdue University to demonstrate the potential of cellulosic nanomaterials as a high performance, environmentally preferable material for the 21st century.

“Using cellulosic nanomaterials as a substrate for photovoltaic cells is just one example of the ability of these materials to provide renewable applications for such high-efficiency products,” said Ted Wegner, Assistant Director of the Forest Products Laboratory.

To date, most solar cells have been built on glass or plastic foundations. Neither is easily recyclable and petroleum-based substrates are not very eco-friendly. Cellulose nanomaterials, on the other hand, are renewable and can be sustainably produced. Use of these wood-based materials also creates a potential use for biomaterials harvested through forest restoration projects aimed at reducing catastrophic wildfires.

“These materials offer a profound opportunity to accelerate forest restoration across America, to protect lives and property from wildfire,” said Michael T. Rains, FPL acting director. “It is estimated that a well-established program in wood-based nanotechnology that creates high-value markets from undervalued woody biomass can help restore 7-12 million forested-acres annually,” said Rains. “This could significantly reduce future fire suppression costs.”

Cellulosic nanomaterials are naturally occurring and possess many outstanding qualities. They have strength properties greater than Kevlar®; piezoelectric properties equivalent to quartz; can be manipulated to produce photonic structures; possess self-assembly properties; and are remarkably uniform in size and shape. Because they are naturally abundant, renewable, and cost-effective, reproduction of cellulosic nanomaterials is expected to reach quantities of millions of tons. This exceeds production projections for many other nanomaterials.

A recent study by Georgia Tech College of Engineering, led by Professor Bernard Kippelen, opens the door for a truly recyclable, sustainable, and renewable solar cell technology.

“The development and performance of organic substrates in solar technology continues to improve, providing engineers with a good indication of future applications,” said Kippelen, director of Georgia Tech’s Center for Organic Photonics and Electronics (COPE). “But organic solar cells must be renewable. Otherwise we are simply solving one problem, less dependence on fossil fuels, while creating another: a technology to produce energy from renewable sources that is not disposable at the end of its lifecycle.”