While photo-voltaic technology is widely available now, and an excellent source of renewable electricity in many places where there is plenty of sunlight, the actual efficiency of the cells in production is currently fairly low (in the low teens typically).
According to research from the NREL [pdf], around 40% of the current US electrical needs could potentially come from rooftop solar. If the rooftop panels were more efficient however, that could be much higher. Researchers are exploring other materials that have the potential to improve the efficiency of photo-voltaic panels.
Consumer solar panels vary in efficiency, but are typically in the upper teens percentage efficiency. There are panels in research environments that have achieved much higher efficiencies, and the efficiencies are rising. What makes perovskites interesting is the extreme rate of improvement in efficiency. In the space of just a few years they have jumped from mid teens into the low to mid twenties.
Perovskites, or more strictly perovskite structures, are any materials with the same type of crystal structure as calcium titanium oxide. These materials have a number of interesting properties, including superconductivity, catalytic behavior and, of course, photovoltaic properties.
In solar applications, they can be made into flexible solar cells or even painted on the sides of buildings. The National Renewable Energy Research Laboratory is doing a lot of work in this area, and the results are exciting. David Moore, a researcher at the laboratory, is quoted in an article on their site as saying:
I believe that perovskite technologies are going to be the future of PV, and probably the future of most optical electronics. Twenty-five years from now, the bulk of the market share being produced for PV will be perovskites. And 50 years from now, silicon will be used for computer chips, and basically nothing else because perovskites work for PV, for photodetectors, LEDs, and lasers. It is a really interesting material.
That’s a bold statement considering all the other photovoltaic technologies in this efficiency comparison chart, but it does seem clear that perovskites will play a significant role in the future of solar energy (and perhaps more).