Geometric adjustment helps boost efficiency and durability of perovskite photovoltaic cells

Perovskite solar cells are shaping up to be one of the most promising elements in the future of solar energy. Lighter, more flexible and potentially cheaper than current silicon-based cells, these photoelectric cells are still saddled by a major challenge: their low stability over time.

Although this crystalline material has been attracting the scientific community’s interest for more than a decade, its high degradation when exposed to ultraviolet radiation, among other factors, has hampered its implementation in the photovoltaic industry.

A recent study carried out by the FQM-204 group in the Department of Physical Chemistry and Applied Thermodynamics at the University of Cordoba (UCO), and in which the Georgia Institute of Technology (U.S.) also participated, has managed to increase the efficiency and durability of these solar cells, due to a variation in the molecular geometry of one of the compounds that are incorporated into the photovoltaic cell.

According to the results of the work published in Materials Today, and as indicated by its main author, Susana Ramos, the study has managed to boost the efficiency of solar conversion into energy to 20.7%, compared to 18.3% obtained without the incorporation of this new compound. In addition, and what seems even more relevant, the performance of the photovoltaic cell remains practically stable after a thousand hours of exposure to the sun.

A subtle geometric fit

The study was conducted on a laboratory scale using small solar cells (2.5 by 2.5 centimeters) and a solar simulator. Among the different sheets of the sandwich structure formed by perovskite layers, the research team incorporated a molecule known as diamine, a compound that the scientific community has been working on for years due to its ability to eliminate surface defects, protect the solar cell, and prevent its degradation.

Another of the participating researchers, Gustavo de Miguel, explained that one of the keys to the work was a subtle but decisive geometric adjustment in the geometry of this diamine, which was given a new structure with a hook-like shape that allows it to be anchored more firmly and establish more solid interactions with the different layers of perovskite, thus guaranteeing a more stable and durable solar cell.

The study, carried out within the framework of the European SUNREY project, represents a significant step forward toward solving one of the great challenges facing the photovoltaic energy sector: ensuring that these cells can remain intact for long periods of time. These solar cells, due to the flexibility of perovskite, could open the door to new applications, such as the roofs of electric cars, or the curved surfaces of buildings, researcher Luis Camacho explained.

However, for this to materialize on a large scale, and, as with any technology under development, it will first be necessary to meet a key challenge: transferring the energy efficiency achieved in laboratory modules to the industrial level.