Peroxide is one of the most promising new materials in solar cell technology. Now, engineers at the University of Rochester have developed a new method to increase the efficiency of the material by more than three times by adding a layer of reflective silver underneath. For most of the past century, silicon has been the material of choice for making solar cells, thanks to its abundance and efficiency in converting light into electricity. But in the last decade, a new competitor has rapidly emerged—peroxide, which is cheaper and has caught up with silicon in terms of efficiency.
Now, a new study has improved the efficiency of peroxides by 3.5 times without even modifying the material itself. Instead, the research team found that adding a different layer of material underneath altered the interactions of electrons in the peroxide, reducing an energy-consuming process.
Peroxides and other photovoltaic materials generate electricity by allowing sunlight to excite electrons within the material, causing them to jump out of atoms and prepare to be guided to produce an electric current. However, sometimes electrons fall back into the "voids" they leave behind, reducing the overall current and thus decreasing the material's efficiency. This is known as electron recombination.
Researchers have discovered that they can significantly reduce electron recombination by placing peroxide on a substrate composed of either a single layer of silver or alternating layers of silver and aluminum oxide. The team says this creates a mirror, producing an inverted image of electron-hole pairs, thus reducing the likelihood of electron-hole recombination. In tests, engineers showed that adding these layers improved light conversion efficiency by 3.5 times.
"A single metal can do as much as complex chemical engineering in a wet laboratory," said Guo Chunlei, the study's lead author. "With the emergence of new peroxides, we can further improve their properties using our physics-based methods."
