U.S. scientists believe they have removed one of the last obstacles to commercializing a more efficient and cheaper solar panel made from an alternative material to silicon called perovskite.
The breakthrough came from using “off-the-shelf” materials to prevent the lead that is used in the light-absorbing layer of the panels from leaking into the environment.
The danger of lead poisoning was viewed as “one of the most vexing, last-mile challenges” facing the development of perovskite panels, explained Kai Zhu, a senior scientist at the National Renewable Energy Laboratory (NREL) in Golden, Colo.
Scientists estimate that the panels are three to five years away from commercial use, which could be widespread because the lead used in them helps raise their power to extract electrical energy from sunlight to close to 25%, higher than most commercially available silicon panels.
Researchers at NREL and Northern Illinois University (NIU) developed coatings for the front and back of test panels. After damaging both sides of the panels and then subjecting them to simulated heavy rain, they found that the films bonded with the lead, keeping more than 96% of it from leaking into the environment.
“The materials are off the shelf, but they were never used for this purpose,” explained Tao Xu, a professor of chemistry at NIU in DeKalb, Ill. “Light must enter the cell to be absorbed by the perovskite layer, and the front-side film actually acts as an anti-reflecting agent, improving transparency just a bit.”
Xu predicted the coatings might be a “game changer” for the potential commercial appeal of the solar panels because their use on homes and in fields is expected to last around 25 years. The toxicity of lead leaching into groundwater from the panels could have reduced their appeal to consumers, despite their increased efficiency.
The new lead-trapping coating was one more breakthrough in a chain of them that began 181 years ago when Lev Perovski, a Russian mineral expert, came across a strange, metallic-looking rock in Russia's Ural Mountains. It was part of a family of different minerals that shared common crystalline structures of cubes and diamondlike shapes.
The material was named for Perovski and was later found to be cheap and abundant throughout the world. But scientists weren't sure what to do with them until 2009, when a Japanese researcher found that perovskite, like silicon, could absorb photons of sunlight and turn them into electricity. Panels made from the material were found to be easier and cheaper to make (Climatewire, April 24, 2017).
Reprinted from Climatewire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news at www.eenews.net.