Solar energy is one of the fastest-growing renewable technologies, but scientists are constantly searching for ways to make solar panels more efficient, affordable, and durable.
A team of researchers at Kaunas University of Technology (KTU) in Lithuania, working with international partners, has now taken a big step forward.
They have achieved record-breaking efficiency in fully inorganic perovskite solar cells and, for the first time, shown that these cells can operate stably for hundreds of hours.
Their results, published in Nature Energy, bring perovskite technology closer to competing with conventional silicon solar cells already on the market.
Perovskite solar cells are attracting global attention because they are lightweight, flexible, and made from inexpensive materials.
They can be manufactured as thin films, which makes them highly adaptable compared to the heavy, rigid panels used today. However, their biggest weakness has been stability.
When exposed to humidity, heat, or air pressure, perovskite materials quickly degrade, losing efficiency and becoming unsuitable for long-term use.
To make the technology viable, scientists must find ways to protect the delicate material.
One promising method is called passivation, a process that makes the perovskite surface more chemically stable, shielding it from the environment while also improving performance.
In hybrid perovskites, this is achieved by applying a thin 2D layer on top of the 3D structure, which improves both efficiency and resistance to moisture. Unfortunately, this approach had not worked for fully inorganic perovskites—the type that offers the greatest long-term potential—because the 2D layers simply would not stick.
The KTU team, led by Dr. Kasparas Rakštys, developed a clever solution. They synthesized new perfluorinated 2D ammonium cations, which use the strong electronegativity of fluorine atoms to enable stable hydrogen bonding.
This breakthrough allowed the 2D layer to finally adhere to the 3D inorganic perovskite, forming a robust protective structure that remained stable even under high temperatures.
This result was considered unlikely until now, making it a significant advance in materials chemistry. By successfully creating stable 2D/3D heterostructures, the researchers not only boosted the efficiency of the solar cells but also dramatically improved their durability.
Using this strategy, the team achieved more than 21% efficiency in standard test cells—one of the best results ever for fully inorganic perovskites. Even more impressively, when they built larger solar mini-modules with an active area hundreds of times bigger than a typical laboratory cell, the efficiency remained close to 20%. The devices also withstood harsh stability tests, continuing to operate for more than 950 hours at 85°C under continuous light.
Although such extreme conditions are rare in real-world use, the results show that inorganic perovskite cells can now approach the reliability standards of commercial silicon panels.
This achievement gives scientists new tools to refine perovskite technology and moves solar power one step closer to a future where it is not only efficient and affordable but also highly durable.
