Trees Used to Create Recyclable, Efficient Solar Cell
Solar cells are just like leaves, capturing the sunlight and turning it into energy. It’s fitting that they can now be made partially from trees. Georgia Institute of Technology and Purdue University researchers have developed efficient solar cells using natural substrates derived from plants such as trees. Just as importantly, by fabricating them on cellulose nanocrystal (CNC) substrates, the solar cells can be quickly recycled in water at the end of their lifecycle. The researchers report that the organic solar cells reach a power conversion efficiency of 2.7 percent, an unprecedented figure for cells on substrates derived from renewable raw materials. The CNC substrates on which the solar cells are fabricated are optically transparent, enabling light to pass through them before being absorbed by a very thin layer of an organic semiconductor. During the recycling process, the solar cells are simply immersed in water at room temperature. Within only minutes, the CNC substrate dissolves and the solar cell can be separated easily into its major components. Georgia Tech College of Engineering Professor Bernard Kippelen says his team’s project opens the door for a truly recyclable, sustainable and renewable solar cell technology.