X-rays reveal in situ crystal growth of lead-free perovskite solar panel materials

University of Groningen scientists are investigating in situ how lead-free perovskite crystals form and how the crystal structure affects the functioning of the solar cells, as part of their quest to find alternatives to lead-based perovskites.

The best results in solar cells have been obtained using perovskites with lead as the central cation. As this metal is toxic, tin-based alternatives have been developed, for example, formamidinium tin iodide (FASnI3). This is a promising material; however, it lacks the stability of some of the lead-based materials. Attempts have been made to mix the 3D FASnI3 crystals with layered materials, containing the organic cation phenylethylammonium (PEA). "My colleague, Professor Maria Loi, and her research team showed that adding a small amount of this PEA produces a more stable and efficient material," says Assistant Professor Giuseppe Portale. "However, adding a lot of it reduces the photovoltaic efficiency".

Perovskite diodes enable bidirectional optical signal transmission between two identical devices

Researchers at Linköping University, in collaboration with colleagues in China, have developed a tiny unit that is both an optical transmitter and a receiver. "This is highly significant for the miniaturization of optoelectronic systems," says LiU professor Feng Gao.

Chunxiong Bao, postdoc at Linköping University, types in a sentence on a computer screen, and the same sentence immediately appears on the neighboring screen, optically transferred from one diode to another. The diode is made from perovskite.

Tackling perovskite solution aging issues could benefit solar cells and promote commercialization

The aging process of the perovskite solution used to fabricate solar cells makes the solution unstable, leading to poor efficiency and poor reproducibility of the devices. Reactants and preparation conditions also contribute to poor quality. To tackle these issues, a research team from the Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) of the Chinese Academy of Sciences (CAS) has studied the aging process of perovskite solution and proposed a way to avoid side reactions.

Researchers try to eliminate solution aging problems in perovskites image

Prof. PANG Shuping, corresponding author of the paper, said "an in-depth understanding of fundamental solution chemistry had not kept up with rapid efficiency improvements in perovskite solar cells, even though such cells have been studied for 10 years... Normally, we need high temperature and a long time to fully dissolve the reactants, but some side reactions can happen simultaneously," said Prof. PANG. "Fortunately, we have found a way to inhibit them."

Efficient tandem solar cell developed using wide bandgap perovskites

An international research team has developed a new type of solar cell that can both withstand environmental hazards and is 26.7% efficient in power conversion.

Highly efficient and stable double layer solar cell developed​ imageStructure and photovoltaic performance for the perovskite-Si tandem device. Image by KAIST

The researchers, led by Byungha Shin, a professor from the Department of Materials Science and Engineering at KAIST, focused on developing a new class of light-absorbing material, called a wide bandgap perovskite. The material has a highly effective crystal structure that can process the power needs, but it can become problematic when exposed to environmental hazards, such as moisture. Researchers have made some progress increasing the efficiency of solar cells based on perovskite, but the material reportedly has greater potential than what was previously achieved.

LayTec’s new InspiRe in-situ tool used for monitoring perovskite formation

Germany-based in-situ metrology system maker LayTec has announced that its new InspiRe system applies high-speed in-situ reflectance measurements for monitoring perovskite thin-film formations during spin-coating and subsequent annealing.

LayTec’s new InspiRe in-situ tool for control of perovskite formation image

In collaboration with professor Norbert Nickel’s group at HZB, LayTec designed the InspiRe in-situ metrology system, which was applied to monitor both spin-coating and annealing. Gathering data at a time resolution on the millisecond scale allows resolving of the kinetics and phase formations during film formation.