Stability - Page 10

Researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) and the University of Toledo have found that perovskite solar cells should be subjected to a combination of stress tests simultaneously to best predict how they will function outdoors.

The team used a state-of-the-art p-i-n PSC stack (with PCE up to ~25.5%) to show that indoor accelerated stability tests can predict 6-month outdoor aging tests. Device degradation rates under illumination and at elevated temperatures are most instructive for understanding outdoor device reliability. The team also found that the indium tin oxide (ITO)/self-assembled monolayer (SAM)-based hole transport layer (HTL)/perovskite interface most strongly affects the device operation stability. Improving the ion-blocking properties of the SAM HTL increases averaged device operational stability at 50°C–85°C by a factor of ~2.8, reaching over 1000 h at 85°C and to near 8200 h at 50°C with a projected 20% degradation, which is among the best to date for high-efficiency p-i-n PSCs.

Researchers from the Indian Institute of Technology Bombay and Germany's Helmholtz Young Investigator Group FRONTRUNNER IEK5-Photovoltaik have designed an inverted perovskite solar device that uses a self-assembled monolayer to suppress nonradiative recombination at the interface between the perovskite absorber and the hole transport layer. The team reported high efficiency for the cell and say it was also able to retain the initial efficiency rating for 3,000 h.

The inverted perovskite solar cell was based on a hole transport layer (HTL) made of a phosphonic acid called methyl-substituted carbazole (Me-4PACz).

Researchers from Princeton University and the King Abdullah University of Science and Technology (KAUST) have connected silicon solar cells with perovskite ones in a tandem solar cell to not only boost overall efficiency, but also to strengthen stability. The results show that the connection protects the frail perovskite solar cell from voltage-induced breakdown while attaining greater efficiencies than either cell can achieve on its own.

The team demonstrated that the tested perovskite/silicon tandem devices are considerably more resilient against reverse bias compared with perovskite single-junction devices. The origin of such improved stability stems from the low reverse-bias diode current of the silicon subcell. This translates to dropping most of the voltage over the silicon subcell, where such a favorable voltage distribution protects the perovskite subcell from reverse-bias-induced degradation.

Researchers from Pennsylvania State University have developed a cost-effective method for creating bio-inspired solar devices that could improve the performance of perovskite solar technology. The team drew inspiration from cell membranes, the protective barriers around cells in all living organisms.

The researchers combined perovskite solar cell material with a synthesized version of natural lipid biomolecules to help protect against moisture-induced degradation. These biomolecules are fatty or waxy materials that don’t dissolve in water. The biomolecules formed a membrane-like layer around the perovskite, boosting stability and efficiency in tests. The approach could have a great impact on how perovskite solar cells are designed.

It was reported that Sekisui Chemical, a Japanese plastics maker, will begin mass production of perovskite solar cells (PSCs) in an effort to catch up with Chinese competitors.

The company will invest more than 10 billion yen (over USD $68 million) to build a new manufacturing facility with an annual production volume of several hundred thousand square meters by 2030.

Researchers from Harvard University have reported a bioinspired liquid-based encapsulation strategy, that offers protection from water without sacrificing the operational properties of the encapsulated materials.

Using halide perovskite as a model system, the team showed that damage to the perovskite from exposure to water is drastically reduced when it is coated by a polymer matrix with infused hydrophobic oil. 

Researchers from China's University of Science and Technology (SUSTech), Chinese Academy of Sciences (CAS), City University of Hong Kong (CityU) and Korea University have developed an effective strategy to modify the Tin dioxide (SnO₂)/perovskite buried interface by passivating the buried defects in perovskite and modulating carrier dynamics via incorporating formamidine oxalate (FOA) in SnO₂ nanoparticles.

Tin dioxide (SnO₂) is a commonly used electron transport material for n-i-p-type perovskite solar cells (PSCs) due to its high light transmittance and electron mobility, suitable energy levels, good stability under UV irradiation, and it can be processed at low temperatures. The buried interface of perovskite/SnO₂ plays a major role in achieving high efficiency and stability. However, the non-exposed buried interface is challenging to study and manipulate.

Researchers from Spain's BCMaterials, University of Barcelona and IKERBASQUE have developed water stable perovskites, by adopting a unique additivization strategy to stabilize the FAPI alpha phase. 

Thanks to their thermal stability along with a monocationic and anionic nature, formamidinium lead triiodide (FAPI) perovskites have emerged as an attractive material to avoid thermal degradation and phase segregation and promising photoactive materials for perovskite solar cells. However, the unfavorable phase transition from cubic (3C) to hexagonal (2H) due to the lower formation energy of the latter hinders its immediate use. Stabilizing the 3C phase of FAPI against atmospheric stresses is a critical challenge in PSC research, and the goal of this recent study.

Researchers from Texas A&M University, Northwestern University, University of South Florida and University of Illinois Urbana-Champaign have studied the fatigue behavior of 2D hybrid organic-inorganic perovskites (HOIPs) in practical applications.

The application of repeated or fluctuating stresses below the material's strength, known as fatigue loading, often leads to failure in 2D hybrid materials. However, the fatigue properties of HOIP materials have remained elusive despite their widespread use in various applications. The research group demonstrated how fatigue loading conditions, wearing different components, would affect the lifetime and failure behavior of the materials. Their results provide insights into designing and engineering 2D HOIPs and other hybrid organic-inorganic materials for long-term mechanical durability.

Researchers from North Carolina State University, National Synchrotron Light Source II at Brookhaven National Laboratory and Rey Juan Carlos University have created a novel materials acceleration platform (MAP), essentially a robot capable of conducting experiments more efficiently and sustainably to develop a range of new semiconductor materials with desirable attributes. The researchers have demonstrated that the new technology, called RoboMapper, can rapidly identify new perovskite materials with favorable properties and improved potential for creating stable and efficient solar cells.

“RoboMapper allows us to conduct materials testing more quickly, while also reducing both cost and energy overhead – making the entire process more sustainable,” says Aram Amassian, corresponding author of a paper on the work and a professor of materials science and engineering at North Carolina State University.