This doesn’t sound logical, but it has been scientifically demonstrated that the efficiency of solar panels can be increased if the panels reflect back much of the light. A team from the University of California, Berkeley, have shown that solar panels should be designed to be more like LEDs, able to emit light as well as absorb it.
“What we demonstrated is that the better a solar cell is at emitting photons, the higher its voltage and the greater the efficiency it can produce,” says Eli Yablonovitch, team leader and UC Berkeley professor of electrical engineering.
In theory, the maximum efficiency of a solar panel is 33.5 percent conversion of incoming photons into electrical energy. Most panels today are around 26%. Even a small improvement would significantly improve the ROI from installing solar panels, and bring the cost of solar closer to grid parity. The Berkeley team has demonstrated an improvement to over 28% in their labs.
Yablonovitch, has founded Alta Devices in the San Francisco Bay Area to commercialize this concept. They have created a prototype solar cell made of gallium arsenide (GaAs),that allows light to escape from the cell by increasing the reflectivity of the rear mirror amongst other things.
More about this promising technology on the Alta Devices website, although they are still quite secretive.