Solar Cell Samples (IMAGE) Northern Illinois University Caption Two laboratory solar cell samples, one (right) with a protective lead-absorbing film applied to the backside. Credit Photo credit: Northern Illinois University Usage Restrictions Please credit: Northern Illinois University License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.