Perovskites have been known for a long time
as materials with many unique and fascinating properties, which
strongly depend on the material composition. Over the last decade,
hybrid perovskites have emerged as promising materials for building
solar cells, which might help to meet our growing energy demand by
harvesting solar energy. Within less than ten years of intensive
research, the efficiency of perovskite solar cells increased
dramatically from the first perovskite sensitized solar cells with
merely 3.8% conversion efficiency to now striking 25% for lab-scale
devices. This impressive efficiency boost within such a short time
might predict that perovskite solar cells will soon compete with
conventional solar cell materials. In comparison, silicon solar cells
have an efficiency of about 27% depending on the construction
type. Even higher efficiencies are achievable upon combining both
perovskite and silicon in tandem cells (29.1% so far). The greatest
advantages of perovskite materials against conventional solar cell
materials such as silicon lie in the fabrication process: hybrid
perovskite materials could be produced from abundant starting
materials using simple processes. As a result, production costs could
be significantly reduced and solar cells could be fabricated easily
and more economically. In addition, perovskite production needs
comparatively little energy input. As a result, the energy balance,
from the production of a perovskite solar cell through its use to its
end, has a higher output than conventional materials. Silicon solar
cells, for instance, are usually fabricated with very energy-intensive
processes. That is why it can take several years to regain the energy
spent for production of silicon solar cells while for perovskite cells
this can be achieved within a few months. In addition, perovskites
exhibit further remarkable properties that open up new possibilities:
they are suitable, for example, for curved, flexible or even
transparent substrate materials. This enables them to be used on bent
surfaces or in elastic components. The easy tunability of perovskite
materials is also a strong benefit, as will be described below.
Figure 1: (right) Perovskite solar cell. |