LSU researchers are building a quantum simulator to study how light interacts with different materials in solar cells to increase their efficiency. 
LSU Physics professor Omar Magana-Loaiza and postdoctoral researcher Chenglong You received a grant from the U.S. Department of Energy to build a one-of-a-kind quantum device. Their research could help scientists find better materials to build solar cells and make them more efficient. 
The sun emits light made up of speeding photons that travel to the Earth, and solar cells convert the energy of those photons into electrical energy. 
Most solar cells are made from crystalline silicon, a semiconductor material that helps transport photons in the conversion of light energy to electrical energy. 
The conversion is not perfect, however, due to photons’ unpredictability and their tendency to cluster in odd places called localization effects. When a photon is unable to “get to the other side,” as Magana-Loaiza explained, its energy is lost.
“Photons can get stuck somewhere in the material,” Magana-Loaiza said. “Some photons can travel here and get stuck here and then they don’t achieve the other end. People have been trying to redesign the materials such that we can collect as much of the light as possible.” 
Finding the best material is not so simple. 
Photons are subject to quantum effects, which means predicting where a photon will end up is a matter of probability. 
“If you think quantumly, there are all sorts of events we’re not considering,” You said. 
“This is a complicated problem that not even a supercomputer can do,” Magana-Loaiza said. “There are multiple combinations and multiple possibilities that can happen and at some point when you start considering all these possibilities, your computer will be frozen.”
The quantum device they’re building will be used to find the optimal conditions for the most light to turn into electrical energy. From there, scientists will have a blueprint of the kind of material that would make the most efficient solar cells. 
Directly testing different materials in a lab is another option, but Magana-Loaiza said this process could take decades. 
“The material science is so complicated,” he said. “We cannot write an equation to model it. The proposal is if we can build this powerful quantum device and then understand how light is collected and transported, then we will know some possible paths to improve.” 
Solar energy is becoming increasingly popular as countries begin transitioning to renewable energy. 
The cost of solar has fallen dramatically over the past decade and increases in efficiency could make it even cheaper, according to the World Economic Forum. 
More efficient solar cells also means less land that would be needed to produce the same amount of electricity. This is important because large-scale solar farms require vast amounts of unused land.  
The quantum simulator will be the first of its kind at LSU and in the United States. Magana-Loaiza said there aren’t many universities or companies building quantum simulators in the U.S. 
“This is very important quantum technology,” he said.