New Material Transforms Smart Windows into Solar Generators

Halide perovskite helps thermochromic windows produce electricity.

Smart windows (smart glass) require little or no introduction these days, as its ability to darken when the sun is hot and lighten up when things are cooler makes it a self-publicizing, adorable and appealing technology to everyone.

Smart Windows (Source: News Center)

Smart Windows (Source: News Center)

However, what if the window didn’t just darken to make life more bearable? What if it could actually generate electricity simultaneously? In the past that would have been considered science fiction, but now – with the use of halide perovskite in photovoltaic glass production, those cards may very well be on the table!

Currently in solar research, perovskite is considered as one of the hottest materials usable and this owed mainly to its high conversion efficiency. Research has now revealed that perovskite works as a stable, photoactive semiconductor, capable a reversible switch between its transparent and non-transparent states, without any form of degradation to its electronic properties.

Halide perovskite has essentially the same crystal structure as the perovskite mineral and is very easy to process. It possesses an excellent phase transition chemistry and essentially can transit from one crystal structure to the other when the environmental temperature is changed slightly or water vapor is introduced.

Halide Perovskite from low-high Temp phase (Source: Berkeley Lab.)

Halide Perovskite from low-high Temp phase (Source: Berkeley Lab.)

When the crystal structure changes, the material moves from its transparent to its non-transparent form. And although these 2 forms have very different crystal structures, the basic composition remains exactly the same, which makes it easier to manipulate the material in a manner that is not yet observed in conventional semiconductors.

Rather notably, the halide-perovskite solar cells exhibit a totally reversible performance, coupled with an excellent stability over multiple cycles of phase transition, without any performance degradation or color fade. And very soon, through this smart photovoltaic windows, a car or even a building will be able to harness solar energy to full capacity.

This research was conducted by researchers at the Berkeley Lab and funded by the Department of Energy (DOE). It was led by Peidong Yang, whose research group consisted of Minliang Lai, Letian Dou and Jia Lin. The result of their study was published in the journal Nature Materials. Other co-researchers involved in the study were from Stockholm University, Lawrence Livermore National Laboratory and UC Berkeley.

For more on solar power research, check out The Future of Solar Power.