As researchers seek the new, next best thing in solar power, they’re exploring new materials and new ways to capture the sun’s energy. Case in point perovskite crystals and recycling light. That’s what new research recently published by the University of Cambridge proposes for a new generation of solar cells.
Scientists at Cambridge investigated hybrid lead halide perovskite crystals and were able to capture additional photons from the photovoltaic process. “Solar cells work by absorbing photons from the sun to create electrical charges,” Cambridge stated. “But the process also works in reverse, because when the electrical charges recombine, they can create a photon. The research shows that perovskite cells have the extra ability to re-absorb these regenerated photons—a process known as ‘photon recycling.’ This creates a concentration effect inside the cell, as if a lens has been used to focus lots of light in a single spot,” the university explained.
“It’s a massive demonstration of the quality of this material and opens the door to maximizing the efficiency of solar cells,” said Felix Deschler one of the scientists working on the research. Deschler co-authored the research, which published in the journal Science on March 25.
In the research scientists shone a laser on part of a 500 nanometre sample perovskite. They were able to measure the photon activity in the sample and detected a near-infrared light emission close to where the laser shone. “Crucially, however, this emission was also detected further away from the point where the laser hit the sample, together with a second emission composed of lower-energy photons,” the university said.
“The low-energy component enables charges to be transported over a long distance, but the high-energy component could not exist unless photons were being recycled,” said lead author Luis Miguel Pazos Outón. “Recycling is a quality that materials like silicon simply don’t have. This effect concentrates a lot of charges within a very small volume. These are produced by a combination of incoming photons and those being made within the material itself, and that’s what enhances its energy efficiency.”
Perovskite crystals show a lot of promise to solar power researchers all over the world. They’re inexpensive to make, can be made from numerous materials, and researchers are quickly ramping up the efficiency of perovskites to harness the sun’s power. They’ve been able to ramp up the efficiency much more quickly than they were able to with many other materials, including silicon, which is what most commercial solar panels use to produce electricity.
“The fabrication methods that would be required to exploit this phenomenon are not complicated, and that should boost the efficiency of this technology significantly beyond what we have been able to achieve until now,” Deschler said.
“Perovskite-based solar cells were first tested in 2012, and were so successful that in 2013, Science Magazine rated them one of the breakthroughs of the year,” Cambridge stated. “Since then, researchers have made rapid progress in improving the efficiency with which these cells convert light into electrical energy. Recent experiments have produced power conversion efficiencies of around 20 percent—a figure already comparable with silicon cells.”Tweet