Researchers design low-temperature method for creating better perovskite crystals

Osman M. Bakr's group in the KAUST Catalysis Facility has designed a low-temperature method that can be useful for making improved single crystal perovskites. The team said that novel perovskites have positive and negative ions in the same plan as the natural perovskite calcium titanate (CaTiO3). Lead halide perovskites, having lead ions as well as halide ions, such as chlorine and iodine in the perovskite mix, are drawing attention for optoelectronic applications.

The crystals have previously been created using high temperatures, however these have created many challenges. Now, the KAUST team has developed a new approach, enabling better crystals to form.

Researchers develop halide double perovskite ferroelectrics

A research group led by Prof. Luo Junhua from Fujian Institute of Research on the Structure of Matter (FJIRSM) of the Chinese Academy of Sciences reported the first halide double perovskite ferroelectric, (n-propylammonium)2CsAgBiBr7, which exhibits distinct ferroelectricity with a notable saturation polarization of about 1.5 μCcm-2.

Halide double perovskites have been found to be a promising environmentally friendly optoelectronic and photovoltaic material, exhibiting inherent thermodynamic stability, high defect tolerance and appropriate band gaps. However, no ferroelectric material based on halide double perovskites has been discovered until now.

Scientists develop new light-emitting material based on perovskite nanocrystals

An international team of scientists recently developed a new composite material based on perovskite nanocrystals to fabricate miniature light sources with improved performance.

Protection of perovskite nanocrystals within porous glass microspheres made it possible to increase their stability by almost 3 times. Moreover, the subsequent coating of these particles with polymers resulted in the fabrication of water-dispersible luminescent microspheres based on CsPbBr3 nanocrystals. This method of fabrication is especially important for the implementation of perovskite nanocrystals in diverse biological applications.

Researchers settle debate over Rashba Effect in perovskite materials

Scientists have theorized that organometallic halide perovskites are so promising due to a highly controversial mechanism called the Rashba effect. Scientists at the U.S. Department of Energy’s Ames Laboratory have now experimentally proven the existence of the effect in bulk perovskites, using short microwave bursts of light to both produce and then record a rhythm, much like music, of the quantum coupled motion of atoms and electrons in these materials.

Research thus far hypothesized that the materials’ extraordinary electronic, magnetic and optical properties are related to the Rashba effect, a mechanism that controls the magnetic and electronic structure and charge carrier lifetimes. But despite intense study and debate, conclusive evidence of Rashba effects in bulk organometallic halide perovskites, used in the most efficient perovskite solar cells, remained highly elusive.

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".