The age old mineral perovskite has been something of a holy grail in solar cell development; the mineral is abundant, cheap, lightweight, and highly efficient when it comes to absorbing light. It does, however, have one major downside: perovskite is water-soluble. In experiments to utilize the mineral, this has meant solar cells have either been light and degradable or heavier and less efficient. But an effort by researchers at Johannes Kepler University Linz in Austria has created a relatively stable solar cell that is just three micrometers thick and yields 12 percent efficiency.
The researchers at Johannes Kepler University created their ultra-thin solar cells with organolead halide perovskites so as to power an unmanned aerial vehicle (UAV). To shield the cells against environmental conditions they introduced a chromium oxide–chromium interlayer which serves to protect the cell’s metal contacts from being damaged by the perovskite, and then applied a clear polymer electrode that had been treated with dimethylsulphoxide.
The resulting cells are highly flexible, and at one square meter weigh just 5.2 grams and are capable of producing 120 watts of power–a record for solar cell efficiency by weight. To test the cells, the team affixed them to both a miniature plane and a blimp, and report they functioned as predicted. Unfortunately, their coatings do not last particularly long, but the researchers note under optimum conditions the cells could continue to work for several months.
And this could provide a highly-efficient way of powering small UAVs. As the team points out in the journal Nature Materials, the cells could power everything “from airplanes to quadcopters and weather balloons—for environmental and industrial monitoring, rescue and emergency response, and tactical security applications.”