A team of physicists and engineers at MIT (Massachusetts Institute of Technology) claims that sandwiching a solar cell between an antireflective coating on the front and a combination of reflective coatings and a diffraction grating on the back can increase the cell's output by as much as 50% for a 2-micron-thick cell.

The aim of the coatings and grating is to keep photons of incoming light bouncing around longer within the thin silicon cell, thereby increasing the likelihood that they will deposit their energy and produce a current rather than just escaping back out into the surrounding air. The team used simulation to experiment with the spacing of the diffraction grating's lines, the number and thickness of reflective coatings, and the thickness of the silicon before verifying the findings in the lab.

Because the work applies to extremely thin silicon cells, the researchers cite reduced silicon cost as another benefit of their approach, stating that their thin films use about 1% as much silicon as conventional solar cells.