Many in the scientific community believe that a mineral called perovskite is the future of solar cell technology. However, efficient perovskite solar panels have been out of reach — at least, until now. Recently, researchers have ‘cracked the code’, so to speak, on how to make these structures efficient enough to really compete with existing technologies.
It’s exciting news for anyone interested in the future of solar as an alternative energy source.
What is Perovskite?
Perovskite is a term for crystalline materials made up of the same kind of basic structure as calcium titanium oxide. Several perovskites occur naturally, including one called loparite and another oxide mineral simply named perovskite.
Confusing? The important thing is that perovskite materials have numerous unique properties that give them potential to be used in numerous technological applications. They are highly conductive and magnetoresistent, and are remarkably efficient as base materials in photovoltaics.
Creating Efficient Perovskite Solar Panels
Not all the sunlight that reaches a photovoltaic solar cell is converted into useable electricity. Much of the current research on solar technology concerns maximizing the conversion efficiency of a cell (which is calculated as the percentage of solar energy that becomes electricity). This innovation is necessary if solar is ever going to compete with conventional energy sources on a large scale.
When research on perovskite solar cells began in 2009, they showed a conversion efficiency of just 9%. However, further work has demonstrated the potential for this technology to surpass those expectations. In 2016, researchers at the US Department of Energy’s Lawrence Berkeley National Laboratory made a discovery that could enable efficient perovskite solar panels to reach 31% efficiency.
Theoretically, 31% is the absolute limit of how efficient this technology could become. That would put it above silicon solar cells, which operate at roughly 22% efficiency today.
Put simply, the discovery related to the surface of the active perovskite layer in solar cells. Viewed under photoconductive atomic force microscopy, it was revealed that the material had a bumpy surface made up of grains with multi-angled facets. It turned out that the difference in efficiency between the different facets was huge — some approached the 31% ceiling, while others performed far below.
Essentially, each tiny facet on the surface of the material acts like its own miniature solar cell. Some are highly efficient, while others underperform. Each of these mini-cells contributes to the efficiency of a perovskite cell overall.
The next step, of course, would be to find ways to control the development of these facets in the process of manufacturing synthetic perovskite. That could be the key to unlocking the full potential of efficient perovskite solar cells.