Eclipsing efficiency

How perovskite tandem solar cells can bring about a brighter future for solar energy | By Zuzanna Malagowska

Eclipsing efficiency
Photo by Joshua Sukoff / Unsplash

We convert sunlight into electricity using solar panels. It is a source of power that will never run out and can minimise negative emissions associated with energy production. It benefits humans, animals, and the environment.

But how solar panels function reveals that there's still work to do in making solar power every bit as brilliant as it promises to be. Solar cells are the little devices that convert sunlight into electricity. The key element in these solar cells is silicon, which accounts for approximately 95% of all solar panels sold today. Silicon is mostly good at absorbing the sun's rays but silicon cells struggle to generate power from certain kinds of sunlight.

That's where perovskite tandem cells come in. Imagine a rainbow of sunshine, and these unique cells can capture colours that others may miss. They combine a unique crystal structure with normal silicon. Bringing together these two materials has the potential to increase the efficiency of solar panels while also making them more affordable and resilient. Even if there are minor issues like dirt, a perovskite tandem cell can still continue to function well.

Over the last 10 years, perovskite solar technology has advanced impressively, surpassing its own efficiency records—which measure the proportion of solar energy converted to electricity. Dr Erkin Aydin has highlighted that these cells have “demonstrated remarkable efficiency, surpassing classical crystalline silicon technologies, and showcasing their potential as a significant advancement in solar cell technology.”

Silicon panels require extremely elevated temperatures and particular conditions to be manufactured, making them more costly. However, perovskites are more flexible; they can be rolled up like a carpet or printed like a painting. So, it is like having solar panels that are not only less expensive but also easier to shape and use in a variety of settings.

Oxford PV is a University of Oxford spin-out founded in 2010 and a pioneer in perovskite solar cells. Oxford PV said that in May 2023 it achieved a 28.6% efficiency for a commercial-size perovskite tandem cell. The company intends to produce its first panels and ramp up manufacturing in 2024.

Professor Stefaan De Wolf told Footprint that “the devices are increasingly becoming more stable” and that “realistically, probably quite soon there may be a first product on the market, but to become a mainstream product perhaps around 5 years”.

Perovskite tandem solar cells are critical in furthering the potential of existing renewable energy technology. Their distinct characteristics equip them to play a vital role in the worldwide transition to sustainable energy sources.

"To avoid the potentially catastrophic effects of anthropogenic climate change, net carbon dioxide emissions from human activities need to approach zero by 2050", Dr Erken Aydin told Footprint. "To this end, many energy-intensive sectors must transition from fossil fuels to electricity generated by renewables. Photovoltaics (PV) are projected to play a key role in this, thanks to its cost-competitiveness, continued technological advancements, and the abundance of solar energy.”

Words By Zuzanna Malagowska