Nanostructures for inorganic photovoltaic cells

Photovoltaic electricity is unanimously regarded as one of the pillars of the energy transition needed to mitigate climate change. In France, various projection reports on the possible electricity mix by 2050 indicate that photovoltaic electricity could account for between 13% and 36% of total electricity production, compared with 2.8% in 2020. Several levers are available to encourage its development, including two main ones:

• cost reduction through economies of scale in the production of mature technologies;

• optimized solar panel performance, which means a smaller footprint for solar power plants, and therefore lower financial and environmental costs.

In this article, we'll be focusing on the second lever, via photovoltaic cell design methods involving nanostructures.

Whether to increase the amount of solar energy absorbed by the solar cell (optical optimization) or to increase the amount of electricity generated from the absorbed light (electronic optimization), nanostructures are at the heart of the light-matter interaction that governs the performance of photovoltaic devices.

Beyond these optoelectronic considerations, it is also possible to take advantage of the properties of nanostructures for other uses, such as the design of so-called "self-cleaning" photovoltaic cells, which limit the maintenance costs usually required to maintain optimum electricity production.

Last but not least, the introduction of a technology on a large industrial scale has environmental consequences that need to be taken into account, especially when the long-term health effects of nanocompounds on humans are still poorly understood.

The aim of this article is therefore to provide an overview of nanostructures applied to inorganic photovoltaic solar cells, both as they exist in industry and as they are being developed in the laboratory. This technical approach is complemented by a historical, economic and environmental background to provide a more complete picture of the situation.