Making Ferroelectric Solar Cells Better

Researchers claim that using several very thin layers of ferroelectric crystals can lead to significantly better ferroelectric solar cell efficiency. But don’t pull the panels off your roof yet. Conventional cells are still much more efficient than ferroelectric devices — at least, for now.

Unlike conventional silicon-based solar cells, ferroelectric cells don’t depend on a PN junction and — in theory — can be cheaper and easier to produce. However, they typically don’t absorb as much sunlight as other materials.

Barium titanate alone exhibits some electric current when exposed to sunlight, but it isn’t nearly as efficient as modern silicon solar cells. However, when the researchers produced a 200 nanometer-thick film “sandwich” made of barium titanate in between layers of strontium titanate and calcium titanate, the output current went up by a large factor. The resulting cells are still not up to par with commercial silicon cells, but they are a lot closer.

The work was done at Martin Luther University Halle-Wittenberg, a German institution. If you do a search, they seem to do a lot with ferroelectric materials like barium titanate.

If you want to roll your own panels, this material might be a bit hard to recreate. You might find some inspiration looking at other thin-film cells, though.

16 thoughts on “Making Ferroelectric Solar Cells Better

  1. As far as I can tell from the linked article, the best efficiency less than 1% and that’s in the ultraviolet where not much of the sun’s energy gets to the ground. Efficiency in the visible region is much worse.

      1. It has always been amazing to me how researchers have the patience to put many years of their life and career toward projects like these, where the initial practicality seems very low compared to existing alternatives. It *might* pay off, and it is great that the research is being done, but I’m myself so impatient that I would have given up after just months.

          1. So fast is rather overstating it – silicon panels definitely degrade, but even decades of degrading on a modern panel is orders of magnitude better than this in power output….

            Still a worthy investigation – as you never know what else you might find unexpectedly, or how much ‘better’ you can make it… Even if its always crap compared to to silicon in power density there are so many other engineering and environmental considerations it might find a great use case.

          2. Indeed they do, depending on who made them. My region has one of the highest installed capacities per capita in the world so we get to see what living with rooftop solar PV is really like. It certainly isn’t the fairytale that the sales people push on you, then again neither is running a diesel generator. The mantra should always be, be realistic and pragmatic, base your decisions on data from field testing over relevant time scales.

        1. To each their own. Society depends on having both innovators and people who unlock the front door at the same time every day.
          Probably the researchers are oriented differently and focus more on the things that they are finding out than the commercial alternatives.
          Also consider that a photoelectric effect that doesn’t generate significant power could be useful as a sensor, if very fast as a communications device (Internet backbone fiber), etc.

  2. Let’s not forget that the leaves on the trees are solar cells of a natural variety. Their growth has been promoted with increasing OCO and higher temperatures. They are about 6 percent efficient, so today’s silicon cells at near 20 percent have outdone nature nicely. Still, I’d rather be in the shade of a nice big hardwood tree than under the back of a solar array. Yes, the solar array is strong enough to power a household air conditioner and this is a serious need in times of global warming, yet when that technology chain fails then the dependence that was established becomes a piece of bad engineering. A system can vaporize or just simply fizzle out in silence. Worst of all is the failing capacitor: a problem that is very inconvenient to resolve. One diode failed short…
    Don’t give up on the trees; at least not completely. Extreme water events will be mitigated first and foremost by root systems that tap deeply underground. Large fields in the midwest drying out as the water table disappears; then a flood of water strips them to nothing, all for want of some rows of trees that the massive combines will not fit through…

    1. I do not think that the choice must be either-or between a solar array and a hardwood tree. They do different things. A hardwood tree makes a very poor roof, does not generate usable electricity, and drops leaves etc. A solar array does not provide a pleasant shady area or turn CO2 to oxygen and wood. Tall trees can certainly block the sunlight from a solar array, you would want them behind…

      I don’t understand “worst of all is a failing capacitor … inconvenient to resolve”. Did one blow up on you?

      Are you saying that hardwood trees are a key to resolving drought then flooding? Any evidence around that? I might expect them to help somewhat, seems unlikely for them to be a complete solution.

    2. Your capacitor fails and civilisation has fallen you can make a leyden jar easily…
      There is a definite fragility to the house of cards of modern life, but with the right knowledge, and access to a good junkpile most of them can be pretty much ignored for quite some time.

      That said, bring back the trees! And a proper native blend of tree, not just all bloody scotch pine for lumber (its got its place, but seriously not massive monocultureal blocks of the bloody things)… Nothing quite an enjoyable in most weathers as a decent forest.

  3. How’s silver as a candidate for this effect. Being approximately the first thing we ever discovered was photosensitive you’d think there would be a way to use that other than photography.

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