Researchers (IMAGE) Northern Illinois University Caption NIU solar cell researchers Xun Li (left), a graduate student in chemistry and biochemistry, and Tao Xu, a professor of chemistry and biochemistry. Photo credit: Northern Illinois University 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.