Stability

Researchers at Austria's Johannes Kepler University Linz have developed lightweight, thin (<2.5 μm), flexible and transparent-conductive-oxide-free quasi-two-dimensional perovskite solar cells by incorporating alpha-methylbenzyl ammonium iodide into the photoactive perovskite layer. 

The team fabricated the devices directly on an ultrathin polymer foil coated with an alumina barrier layer to ensure environmental and mechanical stability without compromising weight and flexibility. 

Scalable deposition of high-efficiency perovskite solar cells (PSCs) is vital to achieving commercialization. However, a significant number of defects are distributed at the buried interface of perovskite film fabricated by scalable deposition, which adversely affects the efficiency and stability of PSCs. Now, researchers at China's Central South University, Hunan Institute of Engineering and  Chinese Academy of Sciences (CAS) addressed this issue by incorporating 2-(N-morpholino)ethanesulfonic acid potassium salt (MESK) as the bridging layer between the tin oxide (SnO₂) electron transport layer (ETL) and the perovskite film deposited via scalable two-step doctor blading. 

The scientists reported that both experiment and simulation results demonstrated that MESK can passivate the trap states of Sn suspension bonds, thereby enhancing the charge extraction and transport of the SnO₂ ETL. 

On March 21, a rocket nicknamed “Cargo Dragon” was launched from Florida, marking the beginning of NASA’s 30th commercial resupply mission to the International Space Station. The 30 tons of cargo aboard included a special payload — the first CubeSat satellite built by a University of Nebraska–Lincoln team and launched into space.

As part of its CubeSat program, NASA in 2021 chose the Nebraska team to include its satellite experiment included as auxiliary payload aboard a future mission to the space station. A few months ago, NASA informed the Nebraska team that their CubeSat would be aboard a SpaceX Falcon 9 rocket scheduled for an early March launch. Big Red Sat-1 was one of four projects from U.S. universities selected for the program.

Researchers from the University of Science and Technology of China, Hefei National Research Center for Physical Sciences at the Microscale, Chinese Academy of Sciences and University of Colorado (CU Boulder) have reported an innovative method to manufacture perovskite solar cells. 

A major challenge in commercializing perovskite solar cells at a commercial scale is the process of coating the semiconductor onto the glass plates which are the building blocks of panels. Currently, the coating process has to take place in a small box filled with non-reactive gas, such as nitrogen, to prevent the perovskites from reacting with oxygen, which decreases their performance. “This is fine at the research stage. But when you start coating large pieces of glass, it gets harder and harder to do this in a nitrogen filled box,” said Michael McGehee, a professor in the Department of Chemical and Biological Engineering and fellow with CU Boulder’s Renewable & Sustainable Energy Institute. 

King Abdullah University of Science and Technology (KAUST) scientists, along with collaborators from Ulsan National Institute of Science and Technology (UNIST) and Chinese Academy of Sciences (CAS), have reported a new strategy to design perovskite solar cells (PSCs) that improves their stability and raises their efficiency.

Image credit: KAUST

Defects at the top and bottom interfaces of three-dimensional (3D) perovskite photo-absorbers diminish the performance and operational stability of PSCs due to charge recombination, ion migration, and electric-field inhomogeneities. In this recent work, the team demonstrated that long alkyl-amine ligands can generate near-phase pure two-dimensional (2D) perovskites at the top and bottom 3D perovskite interfaces and effectively resolves these issues.

Researchers at HZB's HySPRINT Innovation Lab, China's Tianjin University of Technology and Tianjin Institute of Power Sources have developed a non-laser additive method for manufacturing perovskite solar modules, in which an adjustable wire mask (AWM) was used to form the channels that were traditionally scribed by lasers. 

When module channels are made by conventional laser scribing, the heat-sensitive perovskite materials decompose, and the decomposition of perovskites in the open channel leads to reduced module stability. The electrode corrosion caused by the direct contact between the exposed perovskites and the metal electrode significantly increases the series resistance of the module. In this recent work, the team developed a non-laser additive method for manufacturing perovskite solar modules, in which an adjustable wire mask (AWM) was used to form the channels that were traditionally scribed by lasers. This method for making modules prevents contact between perovskites and electrodes. All layers, including perovskites, hole/electron transporting, and passivating and electrode layers, were fabricated via vapor-phase deposition, and by tuning the precursor composition, a power conversion efficiency (PCE) of 21.7% was obtained (0.1 cm²). 

Researchers at City University of Hong Kong, Zhejiang University and The Hong Kong University of Science and Technology have designed a unique triple-layer thermochromic perovskite window (MTPW) that enables sufficient water vapor transmission to trigger the thermochromism but effectively repel detrimental water and moisture to extend its lifespan. The scientists explained they drew inspiration from the structure of medical masks.

Schematic of the trilayer structure and working principle of an antivirus medical mask. b Schematic of the trilayer structure and working principle of the MTPW for repelling water and excess water vapor. Image from Nature Communications

This research addresses the two main challenges hindering the development of thermochromic perovskite smart windows, namely, poor durability and optical blurriness. The MTPW demonstrates superhydrophobicity and maintains a solar modulation ability above 20% during a 45-day aging test, with a decay rate 37 times lower than that of a pristine TPW. It can also immobilize lead ions and significantly reduce lead leakage by 66 times.

Researchers at the University of North Texas, Rochester Institute of Technology, University of North Carolina, National Renewable Energy Laboratory (NREL),  University of Oklahoma and NASA Glenn Research Center set out to deepen the understanding of perovskite photovoltaics' ability to recover, or heal, after radiation damage, by studying the effects of radiation based on different energy loss mechanisms from incident protons which induce defects or can promote efficiency recovery.

Dual dose irradiation experiments. Image from Nature Communications

The team designed a dual dose experiment first exposing devices to low-energy protons efficient in creating atomic displacements. Devices were then irradiated with high-energy protons that interact differently. Correlated with modeling, high-energy protons (with increased ionizing energy loss component) effectively anneal the initial radiation damage, and recover the device efficiency, thus directly detailing the different interactions of irradiation.

Researchers at Ulsan National Institute of Science and Technology (UNIST) and Korea University have reported efficient, stable tin–lead halide perovskites (TLHP)-based PV and photoelectrochemical (PEC) devices containing a chemically protective cathode interlayer—amine-functionalized perylene diimide (PDINN). Their work may advance the commercialization of perovskite solar cells (PSCs) and have potential in green hydrogen production technology, ensuring long-term operation with high efficiency. 

The presence of inherent ionic vacancies in tin-lead halide perovskites (TLHPs) has posed challenges, leading to accelerated device degradation through inward metal diffusion. To address this challenge, the research team developed the chemically protective cathode interlayer using amine-functionalized perylene diimide (PDINN). By leveraging its nucleophilic sites to form tridentate metal complexes, PDINN effectively extracts electrons and suppresses inward metal diffusion.

Researchers at Argonne National Laboratory and Purdue University recently reported an effort to prevent perovskite solar cell degradation by tracking the movement of ions in perovskites. 

The team used X-rays at the Advanced Photon Source and a custom-built characterization platform to reveal the way ions move within different perovskite crystals under ultraviolet radiation (UV). Scientists are interested in testing material stability under UV because it can significantly degrade solar cell performance, sometimes by more than 50%, after extended exposure.