November 2020

Researchers at POSTECH recently developed an organic spacer molecular additive that can improve both the photoelectric efficiency and stability of perovskites.

The POSTECH team, led by Professor Kilwon Cho and Ph.D. candidate Sungwon Song of the Department of Chemical Engineering, succeeded in fabricating perovskite solar cells that are highly efficient and stable by drastically reducing the concentration of internal defects in the crystals as well as increasing the moisture resistance of perovskite by introducing a new organic spacer molecule additive in the perovskite crystal.

A research team at Stanford University has designed a new perovskite manufacturing process. In their work, the team demonstrated an ultrafast way to produce stable perovskite cells and assemble them into solar modules that could power devices, buildings and even the electricity grid.

'This work provides a new milestone for perovskite manufacturing,' said study senior author Reinhold Dauskardt, the Ruth G. and William K. Bowes Professor in the Stanford School of Engineering. 'It resolves some of the most formidable barriers to module-scale manufacturing that the community has been dealing with for years.'

The Department of Science and Technology (DST), under India's Ministry of Science & Technology, has announced the list of solar and storage projects to be carried out by Indian and Israeli researchers with joint funding by the two nations. The project duration will be two years.

Solar projects selected for joint funding include novel electron and hole transport materials for perovskite solar cells by CSIR Indian Institute of Chemical Technology Hyderabad and The Hebrew University of Jerusalem, and mixed-dimensional and hybrid bilayered perovskites for high-stability and high-efficiency photovoltaic devices by CSIR National Institute for Interdisciplinary Science and Technology, Kerala, and Technion Israel Institute of Technology.

A research team, led by Professor Lioz Etgar at The Hebrew University of Jerusalem in Israel, has developed a screen-printed three-layered all-nanoparticle network as a rigid framework for perovskites. This new design, that facilitates the removal and replacement of degraded perovskite in a solar cell, could open the door to recycling PSCs and thus making their market insertion a much safer, "greener" process.

This matrix reportedly enables perovskites to percolate and form a complementary photoactive network. Two porous conductive oxide layers, separated by a porous insulator, serve as a chemically stable substrate for the cells.

Researchers from the University of Cambridge, Imperial College London and Soochow University in China have discovered that unique lead-free perovskite materials could be useful for indoor light harvesting. The team has found that these environmentally friendly materials could harvest enough energy from indoor light to power wireless smart devices.

A novel way to power the multitude of electronic devices we use daily is by converting indoor light from ordinary bulbs into energy, in a similar way to how solar panels harvest energy from sunlight. However, due to the different properties of the light sources, the materials used for solar panels are usually not suitable for harvesting indoor light.

Organic-inorganic hybrid perovskites (OIHPs) have great potential for various applications like solar cells, lighting-emitting diodes (LEDs), field effect transistors (FETs) and photodetectors. Among their most important parameters influencing the power conversion efficiency (PCE) of devices based on perovskite materials is their carrier mobility. However, despite massive progress made by introducing new components into the structure to control the mobility of the carriers, the understanding on the atom level of how the components affect the performance is still lacking.

To address this problem, a research team led by Prof. Luo Yi and Prof. Ye Shuji from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS) has synthesized a series of 2D OHIPs films with large organic spacer cations.

Scientists from several universities in Japan have created a simple method for controlling the introduction of defects, called 'vacancy layers', into perovskite oxynitrides, leading to changes in their physical properties. The approach, reportedly stumbled upon by chance, could help in the development of photocatalysts.

Oxynitrides are inorganic compounds formed of oxygen, nitrogen, and other chemical elements. They have gained much attention in recent years because of their interesting properties, with applications in optical and memory devices, and in photocatalytic reactions, for example.

Researchers at The University of Cambridge and Zhejiang University recently created highly efficient LEDs by depositing mixed-dimensional perovskites on a thin lithium fluoride interface. The fabrication method they used reportedly resulted in LEDs with impressive external quantum efficiencies, while also enabling the deposition of perovskites on a material that they are typically incompatible with.

Image from Nature Electronics

The researchers have been conducting research into perovskite-based LEDs for a few years now. Back in 2018, they created a near-infrared LED using perovskite-polymer heterostructures that achieved external quantum efficiencies of over 20% and internal quantum efficiencies of almost 100%.

A research team, jointly led by Professor Gun-Tae Kim and Professor Jun-Hee Lee in the School of Energy and Chemical Engineering at South-Korea's UNIST has succeeded in developing high-performance perovskite oxide catalysts using late transition metal oxide materials. In the process, the team discovered the reason behind the improved performance of both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which has been explained by the change in the oxidation state of the transition metal caused by the increase in oxygen vacancies.

Perovskite oxide catalysts are composed of lanthanide, transition metal and oxygen. Owing to the excellent electrical conductivity and bifunctional ORR/OER activity, these catalysts have been considered to be an attractive candidate for metal-air batteries or fuel cells, in which opposite reactions, such as charging and discharging occur steadily. However, due to the high cost and low stability of noble metal catalysts, the development of alternatives is strongly desired.

Researchers from South Korea's Ulsan National Institute of Science and Technology (UNIST) have reported a conversion efficiency of 25.17% in a perovskite solar cell, achieved by minimizing the deformation for the microstructure of photoactive layers in the device.

The inner structure of the newly-developed photoactive layer, as well as the working principle of the perovskite cell. Image: Unist

The team explained that the microstructure of these layers, which generate an electric charge and send it to electrodes, can be deformed - which affects the efficiency of the charge transfer itself. 'This is because the extracted electric charges disappear when defects are formed,' they explained.