It was recently reported that Contemporary Amperex Technology Limited (CATL), the Chinese manufacturer of energy devices, has filed to publicize its patents for the designs and manufacturing processes of several PV products.
The patents, which have been applied under the category of solar PV products, cover a backsheet, a transparent substrate, a perovskite PV cell, and a device design.
Researchers from the University of Surrey, Swansea University, University of Sheffield, University of Cambridge and University of Oxford in the UK, China-based CAS and Canada's University of Toronto have fabricated an inverted perovskite solar cell by using a surface modulator that reportedly facilitates superior passivation on perovskite surfaces, increasing overall cell efficiency. As the surface modulator, the scientists tested two organic halide salts known as 4-hydroxyphenethylammonium iodide (HO-PEAI), and 2-thiopheneethylammonium iodide (2-TEAI).
“These modulators can affect the surface energy of the perovskite films,” the team explained. They explained that the two compounds can dramatically reduce non-radiative interfacial recombination. This can have a significant impact on electrical performance in perovskite cells, with implications for open-circuit voltage, short-circuit current, fill factor, and ultimately, power conversion efficiency. They reported that “2-TEAI showed a stronger interaction than HO-PEAI, forming a quasi-2D structure on the perovskite surface without further annealing.”
Researchers from the National Center for Nanoscience and Technology (NCSNT) of the Chinese Academy of Sciences (CAS) and Beihang University have developed a sulfonium cations-assisted intermediate engineering strategy to study the evolution of intermediates and the film properties of quasi-2D perovskites. The researchers developed a facile strategy for intermediate engineering by employing sulfonium cations to regulate the transformation of intermediates during the crystallization process and improve the film quality of quasi-2D perovskites.
The intermediates were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) to reveal the composition and transformation process of the intermediates. The introduction of sulfonium cations inhibited the formation of unfavorable solvated lead iodide and promoted the formation of favorable perovskite intermediates with fiber-like morphology, which is conducive to the formation of high-quality perovskite crystals. The above effects have been confirmed in quasi-2D perovskite with different n values and 3D perovskites.
Scientists from the Ural Federal University (UrFU) and the Institute of Organic Synthesis of the Ural Branch of the Russian Academy of Sciences (along with their colleagues) have proposed a new type of material for transporting electrons in perovskite solar cells, which has a number of advantages.
The team reported that with the new material, they were able to achieve solar energy conversion efficiency of 12%. "The family of molecules we found carries electrons in PSCs slightly worse than the fullerenes used today, but they are about twice as cheap, much easier to produce, and have a number of other technological advantages," says Gennady Rusinov, associate professor at the Department of Organic Synthesis Technology of UrFU.
Researchers at the University of Helsinki are developing thin films for perovskite solar cells, and matching ALD processes.
Doctoral Researcher Georgi Popov focuses on perovskites and atomic layer deposition (ALD). In 2019, He and his colleagues identified suitable chemicals and were able to design a reaction that enabled them to create a metal iodide coating through deposition for the first time. The researchers were able to demonstrate that this can actually be done through atomic layer deposition. The first successful trial was carried out with lead iodide, which was then processed into CCH₃NH₃PbI₃ perovskite through a further reaction. Later on, the researchers also developed ALD processes for caesium iodide and CsPbI₃ perovskite.
Chinese perovskite solar technology company Renshine Solar (Suzhou) has announced achieving steady-state efficiency of 24.50% for all-perovskite tandem cell module, which it called 'a world record'.
It was reported that the efficiency was achieved for a perovskite module with an area of 20.25 cm², which exceeds that of perovskite single-junction components. The new efficiency level has been certified by Japan’s JET, it added without sharing other details.
Researchers from China's Huazhong University of Science and Technology and Singapore's National University of Singapore have introduced an eco-friendly and low-cost organic polymer, cellulose acetate butyrate (CAB), to the grain boundaries and surfaces of perovskites, resulting in a high-quality and low-defect perovskite film with a nearly tenfold improvement in carrier lifetime.
The CAB-treated perovskite films have a well-matched energy level with the charge transport layers, thus suppressing carrier nonradiative recombination and carrier accumulation. As a result, the optimized CAB-based device achieved a champion efficiency of 21.5% compared to the control device (18.2%).
Researchers from Helmholtz-Zentrum Berlin (HZB) and Potsdam University have reported perovskite–silicon tandem solar cells with periodic nanotextures that offer various advantages without compromising the material quality of solution-processed perovskite layers. Textured tandem devices have been presented before, aiming at improved optical performance, but optimizing film growth on surface-textured wafers has thus far remained challenging.
The research team showed a reduction in reflection losses in comparison to planar tandems, with the new devices being less sensitive to deviations from optimum layer thicknesses. The nanotextures also enabled a greatly increased fabrication yield from 50% to 95%. Moreover, the open-circuit voltage was improved by 15 mV due to the enhanced optoelectronic properties of the perovskite top cell. The optically advanced rear reflector with a dielectric buffer layer resulted in reduced parasitic absorption at near-infrared wavelengths. As a result, the team achieved a certified power conversion efficiency of 29.80%.
Researchers from Empa, EPFL, Sichuan University, Jiaxing University, Soochow University, University of Cologne, University of Potsdam, HZB and the University of Oxford have developed a flexible all-perovskite tandem solar cell with a mitigated open-circuit voltage deficit and reduced voltage loss. The team reported flexible tandem efficiency of almost 24% on small area cells using the spin coating method.
Flexible all-perovskite tandem cells are currently less developed than rigid cells, due to a difficult deposition process for the cell's functional layers and a lower open-circuit voltage. This is due to high defect densities within the perovskite absorber layer and at the perovskite/charge selective layer interface.
Researchers from Ulsan National Institute of Science and Technology (UNIST), Wuhan University of Technology and Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory have manufactured high efficiency, stable, and scalable perovskite solar cells (PSCs) via vacuum deposition, a method of fabricating organic light-emitting display devices (OLEDs).
In their study, the research team demonstrated efficient and stable PSCs with a vacuum-processed Ruddlesden-Popper (RP) phase perovskite passivation layer. By controlling the deposition rate of the RP phase perovskite, which directly influenced its crystallographic orientation, the research team successfully obtained a highly ordered 2D perovskite passivation layer.
