The Perovskite-Info newsletter (September 14, 2021)

Researchers from the Australian National University and the University of New South Wales (UNSW) recently used perovskite solar cells for the development of a novel technology for direct solar hydrogen generation (DSTH), claimed to achieve an impressive solar-to-hydrogen efficiency of around 20%.

In DSTH systems, the electricity generated by a PV unit is used to directly drive water-splitting redox reactions without the need for an electrolyzer or complex power infrastructure. Commercial viability, however, remains unattainable despite efficiencies close to 19%, due to the use of expensive semiconductors and noble-metal catalysts.

A joint research team that includes researchers from the Institute of Solid State Chemistry and Mechanochemistry (the Ural Branch of the Russian Academy of Sciences), the Donostia International Physics Centre and the HSE Tikhonov Moscow Institute of Electronics and Mathematics has studied the characteristics of cubic double perovskite oxides.

To date, experimental measurements of the minerals' characteristics have not corresponded to the results of theoretical modeling. In this new work, the researchers set out to better understand this disparity. The data obtained could allow the improvement of low-temperature fuel cell technologies—one of the main alternatives to current sources of electricity.

Researchers from the U.S. Department of Energy's (DoE) Argonne National Laboratory, Brookhaven National Laboratory, Los Alamos National Laboratory, SLAC National Accelerator Laboratory and Taiwan's Academia Sinica have reported the preparation of stable perovskite nanocrystals for LEDs.

Light-emitting diodes made from perovskite nanocrystals (green) embedded in a metal-organic framework. Image from Phys.org

Perovskite nanocrystals' unstable nature has so far hindered their potential to be used as LED materials. However, the research team managed to stabilize the nanocrystals in a porous structure called a metal-organic framework, or MOF for short. Based on earth-abundant materials and fabricated at room temperature, these LEDs could one day enable lower cost TVs and consumer electronics, as well as better gamma-ray imaging devices and even self-powered X-ray detectors with applications in medicine, security scanning and scientific research.

Hanwha Q Cells, a large South-Korean manufacturer of photovoltaic solar cells, has earmarked 1.5 trillion won (around USD$1.28 billion) for investment in production line conversion and research into new solar energy technologies such as tandem perovskite-silicon cells (individual or connected in series).

The investment will be used to boost the production capacity of solar cells and modules to 7.6 gigawatts per year by 2025. "With this investment, we will strengthen our leading industry position while securing competitiveness in the domestic solar industry," said Hanwha Q Cells CEO Lee Koo-yung.

Scientists from China's Nanjing University and Chinese Academy of Sciences have found that a change to the hole transport layer material helped reduce voltage loss in a perovskite solar cell. The discovery demonstrates a promising new way to overcome a major challenge for perovskites – particularly those used as the top layer in a tandem device.

The group of scientists noticed that a large part of the problematic voltage loss occurs at the interface between the active perovskite and the hole transport layer (HTL) that helps to carry a charge out of the device, and decided to experiment with alternate materials to try and limit this issue.

A research group, led by Prof. Han Keli from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS), in collaboration with Prof. Miao Xiangyang's group from Shanxi Normal University, recently explored the colloidal synthesis of all-inorganic rare-earth-based double perovskite NCs with NIR emission, and revealed their exciton dynamics.

Previous studies mainly focused on the photoluminescence (PL) in the visible region, and those on the near-infrared (NIR) PL of lead-free perovskite NCs are rare.

Japan-based global electronics giant Toshiba recently announced a 15.1% power conversion efficiency for a 703cm² polymer film-based perovskite solar module. The result is referred to by the company as 'the highest efficiency yet reported for any large, polymer film-based perovskite photovoltaic module'.

The device was created using a one-step coating method that uses improved ink, film drying processes, and production equipment to form a uniform perovskite layer. The process is said to reduce the number of steps needed for deposition of the MAPbI₃ perovskite layer. The coating speed is said to reach six meters per minute on a 5×5 cm² module, which the company defined as a rate that meets requirements for mass production.

Researchers from ITMO’s School of Physics and Engineering have created a paste, made of titanium dioxide and resonant silicon nanoparticles, meant to increase the generation of photocurrent in perovskite solar cells and maximize their efficiency.

Image by ITMO

One of two strategies is usually used to further boost the efficiency of PSCs: improving the charge collection or increasing light absorption by the charge generating layer. The first strategy also means the need to introduce other substances or 2D structures into perovskites, which makes the resulting devices more expensive. The ITMO team, together with colleagues from Tor Vergata University, went around this problem by using Mie-resonant silicon nanoparticles, as silicon is one of the elements most accessible in nature.

A team of researchers, led by Professor Yabing Qi in the Energy Materials and Surface Sciences Unit at the Okinawa Institute of Science and Technology Graduate University (OIST) in Japan, recently imaged the atoms at the surface of the light-absorbing layer metal-halide perovskite solar cell.

Their findings addressed a long-standing mystery in the field of solar power technology, showing how power-boosting and stability-enhancing chlorine is incorporated into the perovskite material.