South Korean researchers get closer to developing solar energy collecting windows

New semi-transparent cells break energy conversion efficiency record.

Scientists at the South Korea Institute of Energy Research (KIER) have come one step closer to obtaining a technology that could turn windows into solar energy collectors.

While this isn’t actually a new technology, it stands out for high efficiency and duration.

KIER said it has developed semi-transparent perovskite solar cells with an energy efficiency of over 21%, which is a record for this type of technology. Other good news is that 99% of the initial efficiency can be retained in operation for at least 240 hours.

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The breakthrough, which is described in the journal Advanced Energy Materials, is about replacing the metal electrodes of typical solar cells with transparent electrodes, to let light pass through. 

Earlier experiments with semi-transparent materials produced low charge transportation properties and unreliable stability and at a closer examination using electro-optical analysis and atomic-level computational science, KIER researchers found that lithium ions were the problem.

It turns out that lithium ions in the “hole transport layer” of the solar cell – present there to increase its conductivity – diffuse into a metal oxide layer that serves as a buffer and downgrades its useful qualities.

Therefore, the scientists converted the lithium ions into stable lithium oxide, making the cell much more stable.

The KIER’s solution is less expensive than currently existing solar cells and is readily implementable at large scale, according to the study’s authors.

Considering that the traditional solar panels must be adjusted to the building configuration, plus installation costs, manufacturing windows with classes that capture the Sun’s light and transform it into electricity sounds a hellish advantage of the KIER’s technology.

Think of skyscrapers covered in glass, fully independent from the public power grid. Also, solar energy cells can be embedded literally in any materials that are exposed to light.

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And yet, the 21% efficiency is too low for commercial adoption and the KIER’s cells need substantial improvement before mass production.

Another question is weather buyers will like semi-transparent glasses after being used with fully-transparent windows.

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