Stability - Page 13

A research team led by Imec, that also included teams from Hasselt University and Kuwait University, has fabricated a perovskite solar module based on a scalable, stable device stack that can be processed with industry-compatible techniques, such as sputtering, evaporation, and slot-die coating.

The panel is based on 17%-efficient perovskite solar cells built with a p-i-n configuration, an electron transport layer made of nickel(II) oxide (NiOx), a perovskite layer deposited via slot-die coating, an electron transport layer made of buckminsterfullerene (C60) and lithium fluoride (LiF), a bathocuproine (BCP) buffer layer, and a copper (Cu) electrode.

Researchers at Shaanxi Normal University in China have developed an organic-inorganic hybrid perovskite solar cell that uses 2D perovskite crystal as the template for 3D perovskite growth. In the recent study, the team developed a seed-mediated method to in situ grow a layer of 2D perovskite seed for epitaxial growth of 3D perovskite atop it, to construct a high-quality 2D/3D heterojunction. 

It was reportedly found that the epitaxial 3D perovskite film exhibited a preferred direction, which is different from traditional perovskites with a preferred orientation. The oriented perovskite film consists of large-sized grains with low defect density, long charge-carrier lifetime and good stability, resulting in efficient PSCs with a champion efficiency of 24.83%. 

Scientists from Germany’s Helmholtz-Zentrum Berlin (HZB) and HTW Berlin have examined how precursor inks influence the quality of perovskite thin films. The best cells were scaled up to minimodule size. The team showed that when slot-die coating the halide perovskite layers on large areas, ribbing effects may occur but can be prevented by adjusting the precursor ink's rheological properties.

Prof. Dr. Eva Unger's team at Helmholtz-Zentrum Berlin has extensive expertise in solution-based processing methods and is investigating options for upscaling. "Perovskite photovoltaics is the best solution-processable PV technology available," says Eva Unger, "but we are only just beginning to understand how the complex interaction of the solvent components affects the quality of the perovskite layers."

Researchers at China's Shaanxi Normal University and Chinese Academy of Sciences (CAS) have designed a novel strategy to reduce the formation of anions vacancy defects in halide perovskite solar cells. The team reported that the new approach results in higher efficiency and remarkable stability.

The new method, which they defined as 'a one-stone-for-two-birds' strategy, utilized a ligand known as 3-amidinopyridine (3AP) to pin anions in the device. Anions can control the nucleation and growth of the perovskite crystals and act as a passivating agent to improve the crystallinity, thus ensuring improved efficiency. The team says the 3AP molecules deposited on the perovskite layer are able to form strong chemical bonds with the cell's lead(II) iodide (Pb–I) interlayer and, as a consequence, create a sustainable pinning effect.

Scientists China's Zhengzhou University,  Xi'an Jiaotong University and Chinese Academy of Sciences (CAS) have designed a solar cell based on low-dimensional Ruddlesden-Popper (LPDR) perovskite that is said to have improved carrier transport properties.

The team explained that the new cells are more stable compared to regular 3D perovskite solar cells and are suitable for building-integrated photovoltaics (BIPV), conventional solar, and wearable devices.

Researchers at Huazhong University of Science and Technology, Wuhan University of Technology and University of Toronto recently introduced a new approach for fabricating more stable 3D/2D heterostructures, preventing their degradation. Their approach is based on the introduction of an additional layer between the structures; 3D and 2D perovskite layers.

2D and quasi-2D modified 3D perovskite heterostructures (i.e., structures comprised of 3D and 2D perovskite materials) have several advantageous qualities, such as enabling the passivation of defects and a favorable band alignment, which improve a perovskite solar cells' open-change voltage and fill factor. 3D/2D heterostructures are typically created by spin coating an organic cation salt solution on top of a 3D perovskite material and forming a thin 2D perovskite layer on its surface. This process, however, can facilitate the subsequent degradation of the heterostructures in some conditions, due to the diffusion of ions between the 2D perovskite surface and underlying bulk 3D perovskite.

Researchers from North Carolina State University, Pennsylvania State University and University of North Carolina at Chapel Hill have found that channeling ions into defined pathways in perovskite materials improves the stability and operational performance of perovskite solar cells. 

The team's recent study presented a multiscale diffusion framework that describes vacancy-mediated halide diffusion in polycrystalline metal halide perovskites, differentiating fast grain boundary diffusivity from volume diffusivity that is two to four orders of magnitude slower. 

Scientists from The University of Toledo, University of Washington, Northwestern University, University of Toronto and Empa–Swiss Federal Laboratories for Materials Science and Technology, have addressed a major challenge standing in the way of the commercialization of halide perovskite solar cells - their durability - by discovering an ingredient that enhances adhesion and mechanical toughness.

“Perovskite solar cells offer a route to lowering the cost of solar electricity given their high power conversion efficiencies and low manufacturing cost,” said Dr. Yanfa Yan, UToledo Distinguished University Professor of physics and a member of the UToledo Wright Center for Photovoltaics Innovation and Commercialization. “However, we needed to strengthen the emerging solar cell technology’s endurance during outdoor operation”. The technology needs to survive for decades outdoors in all kinds of weather and temperatures without corroding or breaking down.

Researchers at University of Rome “Tor Vergata”'s CHOSE (Centre for Hybrid and Organic Solar Energy), Greatcell Italy, ISM-CNR and ENEA have studied a standard triple cation perovskite (∼1.58 eV) and wider bandgap perovskite (∼1.63 eV) with intention of finding a common strategy to build a robust device stable over time independently of the perovskite used.

The scientists used a combination of additives inside the perovskite ink: ionic liquid 1-Butyl-3 methylimidazolium tetrafluoroborate (BMIM-BF4), alkylamine ligands oleylamine (OAm) and benzylhydrazine hydrochloride (BHC). The recent work reveals that the combination of these additives helps to improve the efficiency and stability of the entire device, reaching a power conversion efficiency up to 21.3% and over 20% for both types of perovskite and stability beyond 1000 h under continuous light soaking.

Researchers from Georgia Institute of Technology, Argonne National Laboratory and Brookhaven National Laboratory have demonstrated that halide perovskite solar cells are less stable than previously thought. Their work reveals the thermal instability that happens within the cells’ interface layers, but also offers a path forward towards reliability and efficiency for halide perovskite solar technology.

The research could have significant implications for both academics and industry professionals working with perovskites in photovoltaics.