Stability - Page 5

Researchers from the Chinese Academy of Sciences (CAS) posit that the efficiency and stability of perovskite modules are mainly limited by the quality of scalable perovskite films and sub-cells’ lateral contact. So, in their recent work, they addressed this by reporting constant low temperature substrates to regulate the growth of perovskite intermediate films to slow down the crystallization process. This is meant to assist in obtaining high-quality homogeneous perovskite films in large scale size, which avoid the effect of the ambient temperature on the film quality. 

Schematic diagram of the fabrication process of perovskite films using low-temperature substrate growth (LTSG). Image from Nature Communications

In addition, a scribing step named P1.5 was added before the top function layers deposition, so the diffusion barrier layer can be formed “naturally” at the interconnection interface without introducing any additional materials, which alleviates the diffusion degradation process. 

Rayleigh solar Tech has announced two significant lifetime stability results. First, a 15cm x 15cm glass solar module exhibited zero degradation after seven months of outdoor testing. Second, a 15cm x 15cm flexible solar module achieved T80 after 1200 hours of damp heat testing.

“Stability is the crux of any perovskite company’s business model” said Rayleigh CTO and Founder, Dr. Sam March. “This is a huge step towards the commercial viability of our perovskite PV. Rayleigh’s all-ambient slot-die coated carbon-based perovskite solar modules are efficient, low-cost, and are stable in the field”, he said.

A research team at City University of Hong Kong (CityUHK) has announced a new generation of printable perovskite solar cells that offer higher efficiency and stability, lower cost and scalability, with a minimal carbon footprint. With funding support from the inaugural Research, Academic and Industry Sectors One-plus Scheme (RAISe+ Scheme) of the Innovation and Technology Commission of the HKSAR government, the team aims to establish a pilot production line within 18 months.

The “Scalable Production of Next-Generation High-Performance Printable Solar Cells” project, led by Professor Alex Jen at CityUHK, was awarded RAISe+ funding to commercialize the technology. Professor Jen is a pioneer in developing perovskite solar cells that has achieved, along with his research team at CityUHK, significant milestones in recent years - such as perovskite solar cells that displayed a power conversion efficiency of over 26% in laboratory testing. They also successfully addressed the common stability issues by demonstrating perovskite solar cells with an estimated lifetime of over 20 years through accelerated aging tests, comparable to that of silicon-based cells in the market.

Researchers from The Hong Kong University of Science and Technology, Oxford University and the University of Sheffield have developed a molecular treatment that significantly enhances the efficiency and durability of perovskite solar cells. 

A key to the solution was their successful identification of critical parameters that determine the performance and lifespan of halide perovskites. The research team investigated various ways of passivation, a chemical process that reduces the number of defects or mitigates their impact in materials, thereby enhancing the performance and longevity of devices comprising these materials. They focused on the “amino-silane” molecular family for passivating perovskite solar cells.

Researchers from Nanjing University of Aeronautics and Astronautics in China and the UK's University of Cambridge have reported a scalable stabilization method using vapor-phase fluoride treatment, which achieved 18.1%-efficient perovskite solar modules (228 square centimeters) with accelerated aging–projected T80 lifetimes (time to 80% of efficiency remaining) of 43,000 ± 9000 hours under 1-sun illumination at 30°C. 

The high stability results from vapor-enabled homogeneous fluorine passivation over large-area perovskite surfaces, suppressing defect formation energy and ion diffusion. The extracted degradation activation energy of 0.61 electron volts for solar modules is comparable to that of most reported stable cells, which indicates that modules are not inherently less stable than cells and closes the cell-to-module stability gap. 

Researchers at MIT have developed a method to synthesize Spiro-MeOTAD, a crucial material for charge transport, without using noble metals. This development led to the creation of a solar cell with 24.2% efficiency, although it demonstrated rapid degradation.

The research team reported that the new method can produce a Spiro-MeOTAD material that remains stable even after 1,400 hours of testing at elevated temperatures (85°C) under continuous one-sun illumination. This durability is critical for materials exposed to the high temperatures and humidity typical of solar panel environments.

Researchers at Hong Kong Baptist University, The Hong Kong University of Science and Technology (HKUST) and Yale University have revealed the existence of surface concavities on individual crystal grains that are the fundamental blocks of perovskite thin films, and examined their significant effects on the film properties and reliability. 

Based on this discovery, the team designed a new way of making perovskite solar cells (PSCs) more efficient and stable via a chemo-elimination of these grain surface concavities.

Researchers at the National Renewable Energy Laboratory (NREL) and University of North Carolina at Chapel Hill have reported a systematic study on the degradation mechanisms of p–i–n structure perovskite solar cells (PSCs) under reverse bias. Reverse bias is a phenomenon that can occur when, for example, an individual cell is shaded and other cells in the module try to push a higher current through it, increasing the temperature and potential damage to the cells. These conditions make solar cells unstable and deteriorate their performance over time.

The team's new strategy could improve the stability of PSCs under reverse bias conditions and facilitate the future deployment of perovskite-based photovoltaics (PVs) in real-world settings.

Researchers at The University of Toledo (UToledo), Northwestern University and University of Washington have focused on the stability of perovskite solar cells, and reported an adjustment to the chemical structure of a key component of a tandem cell that allows it to continuously generate electricity for more than 1,000 hours.

Image from Joule

“State-of-the-art all-perovskite tandem cells with a conventional hole-transfer layer can only continuously operate for hundreds of hours,” said Dr. Zhaoning Song, a co-author and assistant professor in the Department of Physics and Astronomy at UToledo. “Our innovation prolongs the stability of these devices, advancing all-perovskite tandem technology and bringing it closer to practical application.”

Researchers from Peking University, Tsinghua University, Beijing Institute of Technology and Ecole Polytechnique Fédérale de Lausanne (EPFL) have tackled a reproducibility challenge in black-phase formamidinium lead iodide (α-FAPbI₃) perovskites. They explained that while this is the desired phase for photovoltaic applications, water can trigger formation of photoinactive impurity phases such as δ-FAPbI₃. The team found that the classic solvent system for perovskite fabrication exacerbates this reproducibility issue. 

Growth of the photoactive black phase of formamidinium lead iodide (α-FAPbI₃) usually requires dimethyl sulfoxide solvent, but the hygroscopic nature of this chemical also promotes water-induced degradation to the photoinactive phase. the scientists showed that a larger chlorinated organic molecule can form a hydrophobic capping layer that enables perovskite crystallization under humid conditions by protecting growing crystallites from water.