In the world of solar energy, an efficiency improvement of even 0,1% is considered a remarkable achievement. Now imagine what that means exceed by 1,15% what for decades has been considered an insurmountable theoretical limit. That's exactly what he did. Longi with its new tandem silicon/perovskite photovoltaic cell. A conversion efficiency of 34,85%, certified by the prestigious American National Renewable Energy Laboratory, which represents not only a new world record, but a real watershed in the history of solar energy.
How did they do it? The answer lies in a cocktail of innovations involving lithium fluoride, ethylenediaminemonium diiodide molecules, and an asymmetrically textured silicon surface. What do you say? Is it better to speak โeasierโ? Ok. Come on.
Longi, overcome the insurmountable
The limit of Shockley Queisser of 33,7% has for decades been considered an almost insurmountable barrier for single-junction solar cells. This theoretical boundary, calculated in the 60s, has represented the Holy Grail of photovoltaic efficiency.
Longi did something extraordinary: exceeded this limit by more than one percentage point. It may not seem like much, but in the world of solar energy, it's like breaking a world record in the 100 meters by half a second. How will it do it? By combining traditional silicon (which dominates 95% of the photovoltaic market) with perovskite minerals.
The alchemy of materials
The key to the cellโs success lies in an ingenious layered structure. Longi researchers have improved both the blocking of โholesโ (positive charges) and the transport of electrons, using thin layers of lithium fluoride (LiF) and ethylenediaminemonium diiodide (EDAI) molecules.
It's a bit like building a perfect highway for electrical particles: EDAI molecules โpatch overโ the areas that LiF can't cover, creating a virtually obstacle-free energy transport system.
The team said they are on the verge of achieving better structural coupling, using a technology that uses high-pressure silicon cells with an asymmetric surface structure.
What I find most impressive is how Longi has solved one of the classic problems of tandem cells: the interface between different materials. The asymmetric textured surface of their silicon heterojunction cells represents an elegant solution to a complex problem.
Longi, a record-breaking company
It is not the first time the Chinese company is making headlines for its efficiency records. It's as if this company has made breaking boundaries its trademark.
In November 2023, Longi had achieved an efficiency of 33,9%. Then, in June 2024, it had risen to 34,6%. Now, with this 34,85%, it shows that its innovation trajectory continues to point upwards.
And itโs not just tandem cells. This year, Longi set another record with a silicon cell using Heterojunction Interdigitated Back Contact (HIBC) technology, achieving an efficiency of 27,81%โan extraordinary result for a monocrystalline silicon cell.
Implications for the future of solar energy
What does all this mean for us mere mortals? Simple: more efficient solar panels mean more energy from the same amount of space, potentially lower energy costs, and faster adoption of solar energy.
I like to think that we are at the beginning of a new era for photovoltaics. When companies like Longi break theoretical limits that seemed insurmountable, possibilities open up that we could not even imagine before.
One day we will look back on the Shockley-Queisser limit as a historical curiosity, an obstacle that science and human ingenuity have overcome.
