The Potential for More Powerful Solar Panels Made with Ferroelectric and Paraelectric Materials

     New research (August 2021) from Martin Luther University Halle-Wittenberg (MLU) in Germany is suggesting that vast improvements in solar panel efficiency are possible. The suggested improvement was up to 1000 times more efficiency. The new technique involves crystalline layers of barium titanate (BaTiO_3, aka BTO), strontium titanate (SrTiO₃) and calcium titanate (CaTiO₃), alternately placed on top of one another in a lattice structure known as a superlattice. These titanates are known as ferroelectric materials.

I should point out that nothing much has been announced about this particular research for the past few years, at least that is easy to find, so I have my doubts about its ultimate potential for making solar more efficient, especially in the near-term. There has been some 2022 research announcements about other types of ferroelectric materials being integrated with perovskite solar panels but that is all I could find with a quick search. Thus, there are obviously more barriers to the commercialization of these types of panels than the paper referenced suggests. 

“Current solar panels are silicon-based. Barium titanate, for instance, is a mixed oxide of barium and titanium. Ferroelectric materials have spatially separated positive and negative charges, which leads to an asymmetric structure that generates electricity from light. Unlike silicon, ferroelectric crystals do not require a pn junction to create the photovoltaic effect, making it easier to produce solar panels.”

The new structure alternates ferroelectric materials with paraelectric materials. The photovoltaic effect of barium titanate has been known for a while. The big discovery is that “the photovoltaic effect is greatly enhanced if the ferroelectric layer alternates not only with one but with two different paraelectric layers.” These ferroelectric-paraelectric superlattice structures (SLs) revealed that interaction between the alternating lattice layers appears to lead to a much higher permittivity, or easier electron flow due to the excitation by the light photons. Importantly, the research also showed that this increased flow was robust, remaining constant over a six-month time period. MLU physicist Dr Akash Bhatnagar noted: “The layer structure shows a higher yield in all temperature ranges than pure ferroelectrics. The crystals are also significantly more durable and do not require special packaging.”

     Silicon-based solar panels have efficiency limitations. Panels made from these ferroelectric materials have other advantages over silicon panels including lower cost, less space requirements, easier manufacturing, and of course, the potential increased efficiency. However, it is not thoroughly understood how this enhanced photoelectric effect emerges. Researchers are working on prototypes and venture capitalists are hoping for functional deployments over the next few years but that may well be a premature conclusion. As mentioned, the researchers noted: “The enhancement in photocurrent persists across a wide range of temperatures and over long periods of time, indicating the robustness and inherent character of the underlying origin.” This suggests that the observed effects are real, stable, and likely workable into functional devices.

    What the researchers are proposing as the reason for the enhanced effect is “the unison of these two rather discrete phenomena—higher permittivity and lowering of the bandgap owing to a modified electronic structure—culminates into an overall enhanced PV effect in SLs.”

    

Source: Strongly enhanced and tunable photovoltaic effect in ferroelectric-paraelectric superlattices. YESEUL YUN, LUTZ MÜHLENBEIN, DAVID S. KNOCHE, ANDRIY LOTNYK, AND AKASH BHATNAGAR. SCIENCE ADVANCES. 2 Jun 2021. Vol 7, Issue 23. Strongly enhanced and tunable photovoltaic effect in ferroelectric-paraelectric superlattices | Science Advances

 References:

Next-generation solar panels are 1000 times more powerful. JJ Shavit. The Brighter Side of News. April 15, 2023. Next-generation solar panels are 1000 times more powerful (thebrighterside.news)              

Strongly enhanced and tunable photovoltaic effect in ferroelectric-paraelectric superlattices. YESEUL YUN, LUTZ MÜHLENBEIN, DAVID S. KNOCHE, ANDRIY LOTNYK, AND AKASH BHATNAGAR. SCIENCE ADVANCES. 2 Jun 2021. Vol 7, Issue 23. Strongly enhanced and tunable photovoltaic effect in ferroelectric-paraelectric superlattices | Science Advances