Aumentare la fattibilità reale delle celle solari perovskite con amidinio

Rendere la migliore tecnologia solare durevole

Most solar panels are based on two technologies: polysilicon, which makes up the majority of them, and thin-film cadmium telluride. However, there is a third way to make photovoltaic systems, which uses a mineral called perovskite.

This is made of calcium titanium oxide, and this technology has made massive progress in the last few years. From lab prototypes with just 3.8% light-to-power conversion efficiency in 2009, they raggiungiunto 33,9% nel 2024 per un progetto di LONGi Green Energy Technology.

However, perovskite solar panels have a major issue: durability. Most perovskite solar cells last only a few years. This precludes them from being used in any commercial setting, as it kills the profitability of these systems, even with higher efficiency and lower production costs.

So, as long as they cannot compare to the 2-3 decades durability of polysilicon, perovskites will be doomed to niche applications and lab prototypes, missing out on most of the “nuova era solare” that is already upon us.

This is why the announcement of a way to improve perovskite stability 3-fold is a big deal. It was made by researchers at Northwestern University (USA),  Griffith University (Australia), and the University of Toronto (Canada), who published their findings in the prestigious publication Science under the title “Amidination of ligands for chemical and field-effect passivation stabilizes perovskite solar cells¹”.

Vantaggi delle perovskiti

The major advantages of perovskite are its low cost and the possibility of ” printing” solar cells. A big driver of the lower cost is that it can be produced at room temperature, compared to silicon, which requires hundreds of degrees.

Perovskite cells are also flexible, opening new applications like car roofs and drones. It also absorbs a larger portion of the Sun’s light, portando a una maggiore efficienza teorica, of up to 40%.

Titanium is also a relatively abundant metal, so it makes a better alternative to silicon than cadmium telluride. However, potential leakage of heavy metals, notably lead, is a concern that must also be addressed.

Fonte: Research Gate

It should also be noted that silicon-perovskite tandem cells, like the one developed by LONGi, are an option instead of solely perovskite systems.

Proteggere le perovskiti dalla degradazione

Typically, perovskite solar cells use an ammonium-based coating layer to enhance efficiency. While effective, ammonium-based layers degrade under environmental stress, including heat and moisture. This is because the ammonium molecule tends to break down under intense heat and water.

Fonte: Frontiers

This is of course far from ideal for real-life utilization of solar panels, which will need to deal with rain and hot summer days.

This is where the researchers of this study found a solution, by using another type of nitrogen-based compound: amidinium. Amidinium is the ion formed from amidines.

Fonte: Wikipedia

This is a departure from previous research on perovskites, that had focused on improving the stability of the perovskites themselves. Instead, this tries to improve the protective layers.

Miglioramento radicale

Not only did this new approach improve the resistance of the coating on top of the perovskite cells, but it also boosted the overall durability of the solar panel.

“Il nuovo rivestimento era 10 volte più resistente alla decomposizione rispetto ai tradizionali rivestimenti a base di ammonio. Ancora meglio: le celle rivestite con amidinio hanno anche triplicato la vita utile T₉₀ della cella — il tempo necessario perché l’efficienza di una cella scenda al 90% del suo valore iniziale quando è esposta a condizioni estreme.”
Bin Chen – Ricercatore associato di chimica presso Northwestern

Costruire sopra l’innovazione precedente

This is not by far the first breakthrough of this research team.

Another co-author’s team, Ted Sargent, developed in 2022 a perovskite solar cell that broke records for energy efficiency and voltage.

In 2023, his team introduced a perovskite solar cell with an inverted structure, which also improved its energy efficiency. They also incorporated liquid crystals to minimize the defects in perovskite films, leading to enhanced device performance.

It should also be noted that this study was not done only by academics, but was supported by both the private company First Solar (FSLR ), and public institutions like the Department of Commerce, the National Institute of Standards and Technology and the U.S. Department of Energy.

Investire nell’energia solare

Solar energy production is constantly growing at a double-digit rate and will be a key driver to decarbonize the economy. It has still a very long way to go, with the immense majority of our global electricity production, and even more total energy, coming from fossil fuels.

Over the years, it is a sector that has evolved to reward the largest companies, with economies of scale a key factor in managing to generate profit in a very competitive environment. With of course new technologies a potential disrupter of established polysilicon panel manufacturers.

You can invest in solar companies through many brokers, and you can find here, on securities.io, our recommendations for the best brokers in the USA, Canada, Australia, the UK, as well as many other countries.

If you are not interested in picking specific solar companies, you can also look into ETFs like Global X Solar ETF (RAYS), Invesco Solar ETF (TAN), or Global X China Clean Energy ETF (2809.HK) which will provide a more diversified exposure to capitalize on the solar and clean energy industry.

You can also read our article about the “Top 10 Solar Power Stocks to Invest In”.

Azienda solare

First Solar is the largest solar panel manufacturer in the USA and in the whole Western hemisphere, with manufacturing sites in the US, Malaysia, and Vietnam.

The company is not using the classic crystalline silicon technology and instead uses its proprietary thin-film photovoltaics. Based on cadmium-telluride, they are more efficient, are produced at a lower cost, and can easily be mass-manufactured. Thin-film solar panels are also more durable, retaining 89% of the original performance after 30 years.

Fonte: First Solar

Cadmium and telluride are byproducts of the mining for other metals, which means that First Solar products have a minimal impact, using resources that were of little use before. Thin-film panels can also have a high recycling rate.

First Solar’s technological edge, combined with its geographical location, makes it the likely beneficiary of the growing push for Western countries to source their panels from out of China.

The company is ramping up its production capacity quickly, aiming to reach a nameplate capacity of 25 GW by 2026, from the current 11 GW.

Considering its involvement in the research discussed here, the company is also clearly interested in perovskite, at least as soon as these panels are durable enough. It notably commented in its investor presentation that perovskite should have a “development line readied for producing technology samples simulating manufacturing-like condition in Q4 2024”.

First Solar has spent a cumulative $2B in R&D since inception.

Overall, First Solar is a technology leader that stands to benefit from tariffs on Chinese imports, something likely to compensate for the negative effect on the solar industry from Trump’s reelection.

While mostly focused on thin film solar using cadmium telluride so far, its expertise in non-silicon solar panel manufacturing could give it a significant head start with perovskite, especially considering its deep ties to some of the top researchers in this field.

Riferimento allo studio:

^{1. Yang, Y., et al. (2024). Amidination of ligands for chemical and field-effect passivation stabilizes perovskite solar cells. Science, 386(898–902). https://doi.org/10.1126/science.adr2091}