More powerful, cheaper and smaller solar panels are coming to market

Chemists in Hong Kong and London want to bring a new photovoltaic system to market within a few months. It is supposed to be almost a tenth as efficient as the current ones at half the price. Plus, it could be on windows or curved surfaces.

Perovskite – lower price, more power, less space taken

Researchers in London and Hong Kong have improved solar cells made of perovskite. A material that is often described as a miracle for both the future of renewable energy generation and the achievement of zero emission targets. And the price could be 30-50 % lower than today´s silicon panels.

The basis of perovskite are crystals of general formula ABX3, where A and B are two cations, i.e. positively charged particles, and X is an anion, i.e. negatively charged particles connecting the cations. In photovoltaics, there are different chemical groups, depending on their ability to convert light into electricity. But they always have this same configuration, which is looser than the solid structure of silicon. 

The main benefit of this is that perovskite solar panels are lightweight, flexible, more efficient and can be manufactured at lower temperatures and therefore cheaper than conventional silicon panels. Companies can print them on flexible tapes and apply them to windows, thus greatly expanding the potential of photovoltaics. One square metre of silicon panels could replace about 0.6 to 0.7 m² of perovskite photovoltaic cells. 

Until now, the higher chemical reactivity and instability of the miracle material has been the problem. In high temperatures and humidity, its life span is significantly shortened. And that is exactly what a team of scientists from the City University of Hong Kong and Imperial College London managed to solve this year and publish their results in the prestigious scientific journal called Science.

The problematic properties were improved with what is called ferrocene, a compound that has been studied worldwide for decades for its unique properties. It’s got iron in the middle of it surrounded by carbon rings, and it has a lot of electrons. Thus, scientists from London used organometallic compounds on a transition layer that helps the perovskite to better transfer the captured solar energy to the lower layers for gradual conversion to electricity. In addition, they have attached another chemical group to the carbon rings, which also enhances the perovskite consistency throughout the article.

The resulting photovoltaic system was the first of its kind in the world to achieve efficiency of up to 25 % during testing. Which is the fraction of the energy it can harvest from an irradiated surface and convert it into electrical energy. Today’s silicon panels are hovering around 17 %.

In addition, perovskite solar panels with a ferrocene layer have been able to maintain 98 % of their original efficiency after more than 1,500 hours of continuous lighting. They also meet the international standards for advanced photovoltaics and have a high stability in wet heat, i.e. 85 °C and 85 % relative humidity. 

Until the University of Hong Kong and the University of London bring perovskite cells to market next year, they will continue to experiment with other ferrocene configurations that can further increase the performance and stability of the equipment. Silicon panels are efficient but expensive, and we urgently need new solar panels to accelerate the transition to renewable energy. Stable and efficient perovskite cells could eventually expand the use of solar energy – from a source of electricity for developing countries to a new generation of wearables.