CORE-H: the “heart” of 3SUN

It is all a matter of “heart”. Or “core” If research is the heart of innovation for 3SUN, in continuous stretching towards new milestones, the same can also be said for the technology that it develops. CORE-H is, in fact, the jewel in the crown of this company in Catania, the hub around which the production of high-efficiency solar cells rotates, the real heart of each photovoltaic module. And at the same time, it is the key for the future of sustainable solar power production and for 3SUN in the role of leader in Europe's photovoltaic industry.

The quest for efficiency

What is CORE-H’s secret? Cosimo Gerardi, Chief Technology Officer at 3SUN explains, starting from the basics: “A photovoltaic panel is made up of a certain number of solar cells. A solar cell is a device that converts light into electricity, a kind of battery that generates energy only when light is present. If the light goes out, it no longer works”. In brief, CORE-H allows the photovoltaic module’s energy production to be maximised. “The innovative technology developed by 3SUN is based on a “marriage” between two materials: crystalline silicon, whose atoms are perfectly arranged in a mesh based on a cubic structure with centred faces, and a layer of amorphous silicon that is “disorganised”. This combination provides for higher energy efficiency compared to traditional silicon solar cells and other technologies used today for conventional earth photovoltaic panels”. The Hetero-Junction Technology (HJT) cells with CORE-H technology are also more resistant to high temperatures, which means they can maintain top performance even in critical environmental conditions, guaranteeing stable energy production. As well as higher efficiency. “The efficiency of a solar cell is dictated by the amount of light that can be converted into electricity by the cell's active material. Silicon is a material that has a theoretical limit to its efficiency, around 28%. Our technology has allowed us to get quite close to this figure. We are currently at around 25% and we estimate being able to achieve 27%, numbers that are far higher than those of our competitor technologies, thanks to our ability to preserve silicon properties better”.

Bifacial power

“The 3SUN cell is built in a way that it can produce more power on average, so in addition to the efficiency of instant conversion and the higher energy production than other solar cells, on average it produces increasing amounts of energy thanks to the cell's greater thermal stability and bifacial structure”, Gerardi tells us. The extremely high bifacial coefficient means also exploiting the light that is diffused and reflected from the land to the maximum. “If the land is highly reflective, for example if it is lighter in colour, it produces even more; therefore, from a performance point of view, a solar cell of this type has the highest energy production yield that nobody else currently has”. Currently, the bifacial coefficient of conventional photovoltaic modules stands at around 70%, with the best performance at 80%. “With our technology, we can reach 95%, meaning that if we measure efficiency on the back of the solar cell, we obtain 95% of what is obtained on the front. This means that so much is gained on land where light reflection or diffusion can be exploited due to the pale-colour of the land or a high reflection rate. Solar fields are now exploiting the bifacial effect to a high degree and in our case, the higher bifaciality allows us to achieve better energy production”, adds Gerardi.

The great expansion

CORE-H 3SUN is one of the main players in the European photovoltaic sector, aiming to return the leading position in solar energy to the West, not only for the production of solar cells and photovoltaic modules, but also for the production of silicon and glass, currently an area dominated by China and Asia. This can be achieved by making the most of the technological skills and experience in the field of semiconductor physics and transforming it all into innovation. And after the journey begun with a partnership between Enel Green Power, Sharp and STMicroelectronics, in 2011 with a thin-film technology, we can now think in terms of expansion. “We are currently undergoing the increase in production from 200 MW to 3 GW per year”, says Gerardi. “We make better products, larger, differentiated modules, intended for both distributed generation, on the roofs of industrial sheds and buildings, where we can also used modules with a smaller surface but with a high efficient, and on a utility scale, so large solar fields, where the bifaciality factor allows the production of much more energy than the competitors”. The advantage to be associated with the thermal stability that reduces the loss of silicon performance to a minimum with low deterioration of the modules, that last for up to thirty years of use. And in the near future, 3SUN is focusing on Tandem, a technology that associates another innovative material with silicon. “Silicon used only the red part of the solar spectrum. If we add an additional perovskite cell to the silicon cell, we manage to use the blue part too, converting more parts of the solar spectrum into energy. This means an increase in efficient to over the 28% limit, going as far as over 30%. This is the frontier of photovoltaic power today and we are developing it, so we can move it out of the laboratory and onto the industrial production lines”.