In fact, selenium is an integral part of the formulation that resulted in a world record for solar cell efficiency. (sciencedaily.com)
They previously made a range of emerging technologies out of nanocellulose related materials: (1) super clear paper for replacing plastic; (2) photonic paper for improving solar cell efficiency by 30 %; (3) a battery and a supercapacitor out of wood; (4) a battery from a leaf; (5) transparent wood for energy efficient buildings; (6) solar water desalination for drinking and specifically filtering out toxic dyes. (sciencedaily.com)
Nanosolar Reaches Solar Cell Efficiency of 16.4 % and Starts Mass Production (treehugger.com)