After a 170-year delay, the discovery of a strange, metallic-looking rock found in the Ural Mountains in Russia in 1839 has ignited a global technology race for a cheaper, more efficient solar cell. It could seriously disrupt the world's solar market, currently dominated by China.
The features of the rock led to the understanding that there was not a particular mineral involved, but a class of minerals that share a common crystalline structure of cubes and diamondlike shapes. The structure was named for Lev Perovski, a Russian mineral expert who first studied it. He died in 1856. Later, researchers found that mineral deposits containing perovskite structures were 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 could absorb sunlight and turn it into electricity. It was remarkably similar to prepared silicon cells. Only perovskite cells selected stronger photons of sunlight and promised to be much cheaper to prepare than silicon cells, which require 14 steps to manufacture, including preparations requiring the use of high heat, expensive automation and clean rooms.
The potentially cheaper cost of materials and manufacturing has led to a first wave of commercial perovskite ventures, including at least two that are forming in the United States. They are aiming for products that could challenge China's dominance of the global solar market and help spread manufacturing around the world.
“It's amazing how fast this has come along,” said Matthew Beard, a chemist and senior scientist at the National Renewable Energy Laboratory in Boulder, Colo., one of at least 20 research centers and universities around the world that are working with perovskite. He said that while experimenters are still wrestling with a stability problem in perovskite solar cells that, so far, has given them a shorter life span than silicon-based solar cells, there are ways to overcome that. Beard and other NREL researchers think the new crystalline materials could be the basis for a more competitive U.S. industry and the jobs that come with it.
位于美国科罗拉多州博尔德的国家可再生能源实验室（National Renewable Energy Laboratory）的化学家兼资深科学家马修·比尔德（Matthew Beard）说，“这个速度太快了，真令人吃惊。”全球至少有20个研究中心和大学正在研究钙钛矿。他说，实验者们仍然在与钙钛矿太阳能电池的稳定性问题搏斗，迄今为止，尽管这些太阳能电池的寿命比硅基太阳能电池的使用寿命短，但是有办法来克服这一点。比尔德和其他NREL研究人员认为，这种新的晶体材料可能会让美国的工业更具竞争力，并创造更多的工作岗位。
Currently, the solar industry in the U.S. — which invented solar-powered photovoltaic (PV) electricity — generates 73,000 American jobs, according to NREL, and its hiring rate is growing 17 times faster than the U.S. economy.
But China, after a six-year financial sprint to provide lavish government subsidies to its solar market and its industries, remains way out in front. Its silicon-based solar products have become cheap and reliable enough to control 70 percent of the world's trade in solar modules. Meanwhile, the United States produces about 1 percent, according to a new study by Stanford University (Climatewire, March 22.2017).
The study also noted that the perovskite solar cell “has captured enormous interest among solar researchers over the past four years,” and that its efficiency in making electricity from the energy in sunlight — based on laboratory experiments — had soared from 15 percent to over 22 percent in just three years, reaching a level that is competitive with modules made by China.
In an interview with E&E News, NREL's Beard said one “critical factor” in this looming market shake-up “is the potential to be cheaper than silicon.” Another, he noted, was that chemists, like himself, see many potential ways to tune perovskite cells to higher levels of efficiency.
A third emerging factor, being developed by researchers from Stanford University and elsewhere, is the use of perovskite cells to work in “tandem” with commercial silicon cells, mating them together to quickly raise their efficiency.
the machinery will speed up the process of making the basic perovskite material for turning sunlight into electricity. It would then be given a protective covering of glass and encapsulated to protect against water and other substances.
By John Fialka