Source: French to English Tester Published on: 2026-05-01
Source: The Conversation – France in French (2)– By Claudine Katan, Research Director, physicist, National Center for Scientific Research (CNRS)
Thanks to silicon solar panels, electricity generated from photovoltaic sources is now available at a low cost. To go further – to harvest more energy on the same surfaces for reduced costs, and to produce more locally – scientists are developing new materials. Among them, “perovskites” are tunable and compatible with silicon, which makes them particularly promising. What is the current status of these new technologies? What path do they still have to travel?
The silicon sector is the leader in the global photovoltaic technology market, with98%panels sold. Thanks to advances in the field, we now haveDeployable solar electricity at low cost in the vast majority of countries around the world.
The rise of renewable energies, with inleader, the one based on the direct conversion of solar energy into electricity, still legitimate today the development of new photovoltaic technologies combining frugality, efficiency, and longevity. The aim is to further increase conversion efficiencies and minimize costs (environmental impact, manufacturing price, transportation, installation, recycling), but also to guarantee an acceptable lifespan for the manufacturer, the consumer, and the environment.
One of the emerging sectors explored by researchers, start-ups and industrial companies is the one exploiting“perovskite” materials. In this bubbling community, various strategies are developed to combine high yields and a long lifespan.
In our most recent studies conducted with our collaborators and published inScienceandNature Synthesis, we combine several approaches. The robustness of the new perovskite structures is tested under drastic lighting conditions, simulating up to 15 times the power of the sun. These results mark an important milestone that allows for envisioning the transfer of laboratory results to industrial products.
Silicon, king of the market, and emerging sectors
While silicon has become a strategic material at the heart of many electronic technologies, it risks becoming acritical raw material(which presents a supply risk). This is particularly the case in Europe, because thelast active silicon foundry could stop its production, unable to withstand China in a situation of overcapacity.
Among theemerging photovoltaic sectors, that of perovskites is running alone in the lead, as it has joined in terms of performance (for small area laboratory cells, less than one square centimeter) the silicon sector with certified efficiencies exceeding27%. The necessary raw materials are available in Europe.
One of its main advantages is being compatible with traditional silicon solar panels, as these two technologies absorb sunlight in a complementary manner. Thus, by stacking a silicon cell and a perovskite cell, a single so-called “tandem” cell is obtained – which today exceeds 35% for laboratory tandems and27%for modules of more than 14,000 square centimeters (the equivalent of square panels of 1.2 meters on each side), allowing industrialists – yincluded in France— to seriously considertheir marketing.
By increasing the electricity produced for the same surface area of solar panels, a perspective of much faster returns on investment opens up, which could further boost the deployment of photovoltaics.
That is whyDaniel Lincot, member of the Academy of Technologies and a passionate advocate for solar energy for the energy and ecological transition, does not hesitate to draw a parallel with the enormous and unexpected increase in the speeds of sailing boats over recent decades thanks to the addition of submerged lifting surfaces (foils), saying“Perovskites are the foils of silicon”.
If the potential of perovskite materials to significantly increase the efficiency of silicon photovoltaic devices is now beyond doubt, a rapid degradation of the performance during operation of these new solar cells and panels is the main barrier preventing perovskites from entering the solar panel market. To overcome this, scientists are developing different strategies to better organize the material at the microscopic scale.
Perovskite materials: promises, achievements… and challenges
The generic term perovskite refers to a characteristic crystal structure at the atomic scale with octahedra sharing their vertices, forming a three-dimensional (3D) network. The chemical composition of materials exhibiting this structure varies notably withcalcium titanate, a mineral discovered as early as 1839 in its natural environment and which includes oxygen atoms (in blue in the image).
The compositions relevant to photovoltaics and recognized as a new class of semiconductors are synthetic (that is, made by chemists): oxygen is, for example, replaced by iodine while lead (gold-colored) occupies the center of the octahedron, whereas an atom such as Cesium, or a small organic molecule (in pink), loses an electron (called an inorganic or organic cation) and inserts itself into the cavity of the crystal structure between the octahedra.
If this cation is too small or, on the contrary, too large, the network prefers to adopt another crystalline structure that will not have the required properties to produce and then conduct electric current within a solar cell. This results in a color change, with the material shifting from the so-called “black” semi-conducting perovskite phase, which strongly absorbs visible wavelengths of the solar spectrum (below 0.8 micrometers), to a non-perovskite so-called “yellow” phase, indicating that the range of photon energy from the sun that the material is capable of absorbing is much more limited (below 0.5 micrometers).
This color change is also observed when the perovskite material degrades, which greatly reduces the solar energy conversion efficiency. For about ten years, the research community has therefore been striving to understand the degradation mechanisms—and, of course, to contain them.
The latest advances for efficient and more stable perovskite materials
One of the main strategies to increase conversion efficiency exploits perovskite materials which are actually mixtures of different types of synthetic 3D perovskites. Unfortunately, these alloys are subject to phase separation phenomena and/or distortions of the crystal lattice, especially under light irradiation – which leads to irreversible degradation. Moreover, some of these 3D compositions are very sensitive to humidity. Finally, stability issues are also observed at the device level (cell and solar panel), particularly under operational conditions (under light irradiation or when a current passes through the solar cell).
Within the international community, several strategies have been devised to address these problems. For example, theligand engineeringhas taken a predominant place with the exploration of various acids that “passivate” the interfaces (that is to say, prevent the formation of “defects” which capture electrons and therefore limit the generation of an electric current).
Another example is the “millefeuille strategy,” explored since the 1990s: it involves a periodic alternation where the cream corresponds to the organic layer and the paste to the perovskite layer. Solar cells containing these lamellar perovskites have achievedsince 2016record stabilities in operation.
By combining 2D (layered) and 3D perovskites within the same solar cell, one merges the stability of the former with the record conversion efficiencies of the latter. Specifically, a design based on advanced engineering of2D/3D heterostructuresrepresented the state of the art in 2022 and in2024in terms of stability for an operating perovskite solar cell.
Today, our very latest work published in this spring 2026 inSciencebring us even closer to the stability required for commercialization. By understanding the pathway through which synthetic perovskite material transitions from the black phase to the yellow phase, the addition of a specific additive has allowed 2D/3D cells to undergo even more stringent tests: a light flux equivalent to 15 suns!
In parallel, therecent fabrication of multilayer 2D perovskitesnot presenting any structural distortion and allowing the transfer of electrical charges generated by the sun over record distances (beyond 2 micrometers, about 2 to 3 times the diameter of a hair) makes it possible, for the first time, to consider deposits of 2D and 3D layers with similar thicknesses on the order of 300 to 500 nanometers. Such a thickness for the 2D part represents a robust barrier to the penetration of chemical species that would otherwise risk deteriorating the structure. With a thick layer, thepartie 2D pourra aussi contribuer à la production d’électricité. Moreover, the latest synthesized 2D layers haveenergy absorption thresholds sufficiently lowso that it becomes conceivable to test them in combination with silicon in tandem structures while completely freeing oneself from the 3D part.
The projectSURFING(ANR-23-CE09-0001) is supported by the National Research Agency (ANR), which funds project-based research in France. The ANR’s mission is to support and promote the development of fundamental and applied research across all disciplines, and to strengthen the dialogue between science and society. For more information, visit the ANR website.ANR.
Claudine Katan is a member of the GDR HPERO.
George Volonakis received funding from the National Research Agency for the CPJ project and the SURFIN project (ANR-23-CE09-0001).
Jacky Even is a member of the GDR HPERO and has received funding from the Institut Universitaire de France.
Aditya Mohite does not work for, advise, hold shares in, or receive funds from any organization that could benefit from this article, and has declared no other affiliations than his research institution.
–ref. Photovoltaic: the latest advances in “perovskites,” the emerging sector that aims to boost silicon –https://theconversation.com/photovoltaic-what-the-latest-advances-in-perovskites-the-emerging-sector-that-wants-to-boost-silicon-280612