The new material slows down the cooling of 'hot' electrons in solar panels by a thousand times
- Tin-based material slows the cooling of 'hot' electrons by 1000 times.
- The effects of the 'hot phonon bottleneck' and Burstein-Moss work together.
- This opens the possibility of surpassing the historical efficiency of solar panels at 33%.
The efficiency of most modern photovoltaic modules is limited by the fact that some photon energy is lost as heat. When light is absorbed, electrons gain additional energy and become 'hot', but almost instantly give it up to phonons, which reduces the potential power output.
Research in Groningen
A group of physicists from the University of Groningen studied a material that contains tin and found that the cooling process of 'hot' electrons in it slows down by about a thousand times. This makes the material promising for the creation of so-called 'hot' (hot-carrier) solar cells capable of utilizing a large portion of photon energy.
The authors explained the unusual behavior with two well-known physical mechanisms that act simultaneously in this case. The first is the so-called 'bottleneck' of phonons, where the energy environment around the electrons heats up quickly, and then the electrons begin to reabsorb some of this thermal energy, maintaining a high level of excitation.
The second mechanism is the Burstein-Moss effect. Under intense illumination, the lower energy levels become filled, creating a 'bottleneck' that hinders the transition of other electrons to lower states. As a result, 'hot' electrons find it more difficult to release excess energy.
The combination of these two phenomena results in electrons retaining their high energy significantly longer than in ordinary semiconductors. Scientists compared the situation to passengers boarding an airplane: the first take their seats at the front, while the others are forced to move further back, which slows down their movement.
The publication of results in the journal ACS Energy Letters (2026) confirms that the joint action of the phonon bottleneck and the Burstein-Moss effect may be key to overcoming the so-called Shockley-Queisser limit, traditionally estimated at 33% conversion of solar energy into electricity.
If the developed material can be integrated into commercial solar cells, it will significantly increase their output power, especially under strong solar radiation conditions. This technology could be an important step towards transitioning to cleaner energy sources and reducing dependence on fossil fuels.
The research has already attracted the attention of industry experts, and further work is focused on scaling up the production of the material, as well as studying its stability under prolonged exposure to sunlight.
Source: 3DNews
