Scientists from Skoltech (Skolkovo Institute of Science and Technology), Research Centre for Medical Genetics, Federal Research Center of Problems of Chemical Physics and Medicinal Chemistry and Zhengzhou Research Institute of HIT have studied the toxicity of materials used in perovskite solar cells.

They concluded that once the remaining technological hurdles are overcome, mass production of this potentially cheap and efficient alternative to silicon-based photovoltaics should not cause any significant environmental risks and health hazards. The study draws attention to perovskite components other than lead, suggesting that metal's toxicity, by comparison, could be overestimated.

Nano-textured surfaces are an interesting approach for optimizing the optical characteristics for monolithic perovskite/silicon tandem solar cells. Scientists from Germany’s Helmholtz-Zentrum Berlin (HZB) have examined the development of different textures of silicon surfaces using various commercial additives and their performance in silicon heterojunction (SHJ) and SHJ–perovskite tandem solar cells.

The team performed optical and electrical characterization and found that nano-textured surfaces can compete with standard textured surfaces, yielding higher average efficiencies in single junctions. In addition, their compatibility with solution-processed perovskite top cells was demonstrated in the recent study, yielding a perovskite/silicon tandem solar cell efficiency of >28% on a bottom cell with nano-texture on both sides.

Researchers at South Korea’s Ulsan National Institute of Science and Technology (UNIST), Chonnam National University and Pohang University of Science and Technology (POSTECH) have developed a unique perovskite solar cell that uses alkylammonium chloride (RACI) to control the formation of defects in the perovskite layer.

The US National Renewable Energy Laboratory (NREL) has certified the South Korean research team's cell's 25.73% efficiency. The champion device built by the scientists reached an efficiency of 26.08%.

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. 

Researchers from The Hebrew University of Jerusalem in Israel have reported the fabrication of flexible and semitransparent perovskite-based solar cells.

Much of the research in the field of building-integrated photovoltaics is focused on semitransparent perovskite solar cells on glass substrates, which can be utilized as glass windows during the construction of the buildings. In their recent study, the team chose to develop cells that can be used in existing windows through a retrofitting process.

Scientists from the University of Konstanz in Germany, Quaid-i-Azam University and Kohsar University Murree in Pakistan and Huazhong University of Science and Technology in China have fabricated an inverted perovskite solar cell with a passivation technique utilizing a mixed solvent vapor annealing method based on ethylenediamine (EDA).

The team managed to show how simple passivation can improve both the performance and operational stability of a perovskite solar cell. The scientists said EDA has been used in previous research projects to suppress the defect states in different kinds of perovskite. However, the exact way that EDA contributes to the morphology, defect passivation and optoelectronic properties of perovskite films was unclear.

Researchers from Nanyang Technological University, Singapore (NTU Singapore) and the Institute of Materials Research and Engineering (IMRE) at the Agency for Science, Technology and Research (A*STAR) in Singapore have developed a method for capping materials based on non-toxic metals being used in the manufacture of perovskite solar cells.

(Left) A diagram showing the different layers of the perovskite solar cell capped with the zinc-based capping material fabricated by the researchers. (Right) The dotted green rectangle indicates the active region of the perovskite solar cell that captures sunlight and converts it to electricity. Image: NTU Singapore / Nature Energy

Perovskite solar cells are made of several layers of materials, including a perovskite layer that harvests light and a capping layer. The capping layer is coated onto the perovskite layer to protect the solar cell from environmental stresses such as heat and moisture and to boost the performance of the cell. To ensure that the capping layer is compatible with the underlying perovskite layer, researchers typically use an approach called the half precursor (HP) method to fabricate the capping layer. One of the precursor chemicals is first deposited on top of the perovskite layer which provides the other precursor. Through a process known as cation exchange reaction, the deposited precursor then reacts with lead ions present in the perovskite layer beneath to form a lead-based chemical compound that makes up the capping layer. As a result of the HP method, lead is also present in the protective capping layer. A method that enables non-toxic metals to be used in the capping layer could be a game-changer for perovskite solar cells.

Researchers from Eindhoven University of Technology and TNO at Holst Centre have developed a sensor that converts light into an electrical signal at an astonishing 200% efficiency – a seemingly impossible figure that was achieved through the exceptional nature of quantum physics.

SA schematic of the photodiode architecture

The team of scientists sees its invention potentially used in technology that monitors a person's vital signs (including heartbeat or respiration rate) from afar, without the need for anything to be inserted or even attached to the body.

Researchers from Korea's Institute for Basic Science (IBS), Chinese Academy of Sciences, the University of Rochester in the U.S, and The Australian National University have increased the photoresponsivity of a lead-halide perovskite for solar cell applications by 250%. They created a perovskite film with a plasmonic substrate made of hyperbolic metamaterial and characterized it with transition dipole orientation.

The team has considerably reduced electron recombination processes in lead-halide perovskites (LHPs) used for solar cell applications. Recombination 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.

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.