Scientists from Kaunas University of Technology (KTU) in Lithuania, in collaboration with international partners, have announced a significant breakthrough in the field of fully inorganic perovskite solar cells, achieving one of the highest efficiencies ever reported for this class of materials—exceeding 21 percent. Crucially, these advanced cells also demonstrate unprecedented long-term operational stability, operating for over 950 hours at 85°C under continuous illumination. This dual achievement marks a pivotal step towards the commercial viability of next-generation solar power technologies.
Record-Breaking Efficiency and Stability for Fully Inorganic Cells
The international research team’s findings, published in the esteemed journal Nature Energy, highlight an efficiency exceeding 21 percent for fully inorganic perovskite solar cells. This is a remarkable achievement, especially when considering the enhanced stability simultaneously demonstrated. The cells maintained stable operation for more than 950 hours at a high temperature of 85°C under continuous light exposure. This level of stability approaches the reliability standards of commercial silicon solar cells, addressing one of the most significant barriers to the widespread adoption of perovskite technology.
Beyond laboratory-scale devices, the researchers successfully fabricated perovskite mini-modules with active areas more than 300 times larger than standard test cells, achieving an efficiency of nearly 20 percent. This successful scale-up underscores the practical feasibility of the technology for broader commercial applications, moving beyond theoretical performance to demonstrable real-world potential.
The Quest for Durable Inorganic Perovskites
Perovskite solar cells (PSCs) have emerged as the fastest-advancing solar technology due to their excellent optoelectronic properties, low production costs, and versatile applications, including lightweight, thin-film, and flexible designs. However, the progress of these highly promising cells has been hampered by their inherent instability, particularly for hybrid organic-inorganic perovskites. The organic components in these hybrid materials are susceptible to degradation when exposed to environmental stressors like humidity, temperature fluctuations, and pressure, leading to a rapid decline in efficiency and material integrity.
Fully inorganic perovskites, which replace the organic components with inorganic cations like cesium, offer a compelling solution to this stability challenge. By eliminating the volatile organic elements, these materials inherently possess greater thermal and environmental stability. The recent breakthrough by the KTU-led team specifically targets this critical aspect, demonstrating that high efficiency does not have to come at the cost of durability for inorganic perovskite systems.
Previous Milestones in All-Inorganic Perovskite Development
While the recent KTU achievement sets a new benchmark for combined efficiency and stability in fully inorganic perovskites, the journey to this point has seen several notable advancements:
- 2023 Breakthroughs: In August 2023, an international research team developed all-inorganic phase heterojunction perovskite solar cells with a certified efficiency of 21.59%. These devices also showed good stability, retaining over 90% of their initial efficiency after 200 hours under ambient conditions.
- Earlier Efforts: Previous studies on all-inorganic CsPbI2Br perovskite solar cells reported efficiencies exceeding 13% in 2018. Further research demonstrated power conversion efficiencies up to 14.45% for inorganic perovskite solar cells, a figure highlighted at the time as one of the highest reported. These earlier advancements paved the way for the more recent records by progressively enhancing material design and fabrication techniques.
These incremental improvements underscore the dedicated global research effort to unlock the full potential of inorganic perovskite materials for solar energy conversion.
Perovskite Solar Cells: A Broader Efficiency Landscape
It is important to distinguish the achievements in fully inorganic perovskite solar cells from the broader category of perovskite solar cells, which often includes hybrid organic-inorganic variants. The overall field of perovskite photovoltaics has seen staggering progress:
- Single-Junction Records: As of 2025, the highest efficiency for a single-junction perovskite solar cell stands at 27.0%, as certified by the National Renewable Energy Laboratory (NREL). In November 2023, Northwestern University researchers also reported an NREL-certified efficiency of 25.1% for inverted perovskite solar cells, employing a dual-molecule solution to reduce efficiency losses. Prior to this, in June 2023, scientists from the National University of Singapore (NUS) achieved a record of 24.35% for a 1 cm² perovskite solar cell.
- Tandem Architectures: Even higher efficiencies are being achieved with tandem solar cells, which combine perovskite layers with other materials like silicon. Perovskite-silicon tandem solar cells have reached power conversion efficiencies of 34.9% (as of 2025), surpassing the maximum efficiency of single-junction silicon cells. All-perovskite tandem cells have also achieved efficiencies of up to 31.9%. These tandem structures capture a broader spectrum of sunlight, pushing efficiency limits further.
While these higher figures demonstrate the incredible potential of perovskites generally, the latest achievement in fully inorganic systems specifically addresses the crucial long-term stability required for practical deployment.
Overcoming Challenges: The Role of Passivation and Heterostructures
The key to the recent inorganic perovskite breakthrough lies in sophisticated materials engineering, particularly in the realm of surface passivation. The KTU-led team successfully developed and integrated a novel passivation strategy to create stable 2D/3D heterostructures within the fully inorganic perovskite solar cells.
Traditionally, creating such structures in fully inorganic perovskites was considered challenging. Passivation involves rendering the perovskite surface chemically inactive, mitigating defects introduced during production, and enhancing resistance to environmental factors like moisture and temperature. This innovative approach not only protects the material from external degradation but also improves its intrinsic efficiency, marking a significant advancement in materials chemistry.
Towards Commercialization and a Sustainable Future
The convergence of high efficiency and exceptional stability in fully inorganic perovskite solar cells brings this next-generation technology significantly closer to commercialization. Dr. Kasparas Rakštys, a researcher at KTU, emphasizes that perovskite solar cells are “one of the fastest-growing solar technologies in the world – they can be lightweight, thin-film, and flexible, and most importantly, they are made from inexpensive materials.” These characteristics position them as a compelling alternative to traditional silicon-based photovoltaics, with the potential to reduce production costs and expand the range of solar energy applications.
By demonstrating both high efficiency and extended operational lifetimes, the KTU-led team’s work addresses the core challenges that have hindered widespread adoption. As global demand for clean and renewable energy intensifies, advancements like these are crucial for accelerating the transition to a sustainable energy future, offering a path for practical, scalable, and economically viable solar technologies.
