Experts spent decades searching for the material that would best enable us to harness solar energy – and they did so in part thanks to monocrystalline silicon. Now, however, perovskite solar panels have emerged, which have extremely high efficiency… or so it seemed. A group of researchers has sent out a clear message: we are moving too fast, and we must give them time.
Perovskite solar panels, the breakthrough we have been waiting decades for
Perovskite solar cells are a relatively new as well as emerging subset of solar cells which have demonstrated significant efficiency increase only recently. Perovskites are crystalline materials that possess excellent light absorption characteristics.
The common name for these perovskite materials is a hybrid of the organic-inorganic lead or tin halides, but they are also researching some all-inorganic alternatives as well. The perovskite solar cell is made of a perovskite film as a core and two charge-transporting layers sandwiched before the whole cell is encapsulated in a solar cell architecture.
The passing of the light through the perovskite layer makes its electrons to be elicited and jump from the valence band to the conduction band creating electrons-hole pairs. The charge carriers such as holes and electrons are moved in the charge transport layers to make the electric current.
There is an important characteristic of perovskites, and that is wide light absorption range across visible spectrum, hence, they can create sufficient light absorbance via a thin film. In addition, they boast of large diffusion lengths and slow charge recombination rate.
This is the efficiency record that has shocked researchers
Researchers have made remarkable progress with perovskite solar cells in recent years, rapidly achieving higher efficiencies in the lab. In 2021, a team at Oxford University set a new record with a perovskite-perovskite tandem solar cell reaching 29.52% efficiency.
This surpassed the previous record of 29.15% also held by Oxford. Early perovskite solar cells had efficiencies of only 3-4% just a decade ago. Other groups have reached notable milestones as well. Scientists at the Swiss Federal Laboratories for Materials Science and Technology (EMPA) produced a cell with 25.5% efficiency in 2021.
Researchers at the University of New South Wales achieved 25.5% efficiency with a single junction perovskite cell in 2020. The U.S. Department of Energy’s National Renewable Energy Laboratory certified a 25.2% efficient perovskite cell in early 2022.
Experts urge caution and downplay optimism: still need to give them time
Although the progress achieved by perovskite solar cells is incredibly impressive for such a short period of time, theorists insist that research should continue, since there are some factors that could hinder widespread adoption.
Indeed, the main problem is in turning perovskites into solar cells that are more stable, durable and long-lived. But nowadays the most of perovskite cells are rapid to breakdown when they are being in moisture, and UV light.
Investigators are doing different strategies such as durable protective coating and chemicals to improve the durability of the cells, but the inventive breakthrough has not yet appeared.
Furthermore, beside the stability problem, one of the main challenges is to increase the perovskite production to industrial scale level, but it needs to be done without loss in effectiveness and quality.
The materials and manufacturing procedures in great laboratories could not be chartered to industry level production. Deep learning and bias in artificial intelligence will continue to develop.
As you can see, perovskite solar panels are designed to give us a qualitative leap in renewables, but we do not know how far we can go. Time will tell how much we gain in efficiency and, above all, it will clear up the big question: will it extend the useful life of photovoltaic cells even further or will it leave it in the dust? Everything remains to be seen.