Solliance and U.S-based MiaSolé announced a new record - power conversion efficiency of 26.5% on a tandem solar cell that combined a top rigid semi-transparent perovskite solar cell with a bottom flexible copper indium gallium selenide (CIGS) cell.

This impressive efficiency was achieved by optimizing the bandgap and the efficiency of both the rigid semi-transparent perovskite top cell and the flexible CIGS bottom cell. The CIGS was roll to roll produced on steel foil, with a power conversion efficiency of 20.0%.

Scientists at Shaanxi Normal University in China have demonstrated a new, simpler technique for manufacturing tin-containing perovskite solar cells (PSCs).

To improve PSC device stability, researchers tend to focus on improving either the perovskite layer or the tin-based electron transport layer (ETL) of the PSC. The new research, however, uses a new dual passivation technique that stabilizes both tin in the ETL and elements in the perovskite film in one step.

Researchers from UCLA, NREL, The University of Toledo, Yangzhou University, Soochow University, Monash University and Lawrence Berkeley National Laboratory, have found that perovskites have a previously unutilized molecular component that can further tune the electronic property of perovskites.

Schematic of perovskite material with organic molecules that can add to its electronic properties. Credit: Jingjing Xue and Rui Wang/UCLA Samueli School of Engineering

Perovskite materials have a crystal-lattice structure of inorganic molecules like that of ceramics, along with organic molecules that are interlaced throughout. Up until now, these organic molecules appeared to only serve a structural function and would not directly contribute to perovskites' electronic performance.

An international collaboration led by Swansea University called SUNRISE project was launched to accelerate the commercialization and deployment of low-cost third generation solar energy technology. Initially formed in 2018 between five UK and five top-tier Indian institutions, the project now includes a range of academic and industrial partners from around the world. In 2019, the project also received £800,000 by the UK government to support its activity.

The team has installed a solar-powered, hybrid ultra-capacitor (HUC) energy storage system in two different village schools in India. Image from The Engineer

With uptake of solar technology in the developing world hampered by the relatively high installation and maintenance costs of traditional silicon-based solar panels, SUNRISE is focusing its efforts on perovskite solar cells (PSC) which are based on low-cost, earth-abundant, sustainable materials and are thought offer a more affordable solution.

A multi-institution team of researchers, led by the Davidson School of Chemical Engineering at Purdue University, has reported a breakthrough in the flexible solar cell field that may contribute to the development of solar cells on flexible surfaces, including ultra-flexible and wearable energy-harvesting devices.

'Our research is unique in that we have created the first mechanically self-healing perovskite material,' says Blake Finkenauer, lead author of the study and a fourth-year graduate student with Dr. Letian Dou, the Charles Davidson Assistant Professor of Chemical Engineering at Purdue. 'Self-healing mechanical damage has only been realized in the organic materials field, typically with insulating materials. By joining dissimilar perovskite and polymer materials, a composite material with both semiconducting and self-healing properties is realized. The polymer acts as a molecular bonding agent with the crystals, which improves both the thermal and mechanical stability compared to the pure perovskite material".

A new EU project called "CITYSOLAR" aims to revolutionize the market for transparent solar cells for windows by combining two photovoltaic (PV) technologies in a tandem configuration. The project has received 3,779,242 EUR in support from the H2020 framework programme. Transparent solar cells for windows have been known for several years, but are still not sufficiently efficient - which is what the new project will attempt to change.

'We develop new innovative concepts within light management and solar module integration that are specifically targeted at new promising organic and hybrid thin film PV technologies, and by that we go significantly beyond state-of-the-art in terms of efficiency for transparent photovoltaics. It's a revolutionary new concept,' says Professor Aldo di Carlo, Cnr-Ism, who is coordinator of the new project and is thrilled about the support of "CITYSOLAR" from the H2020 framework.

Researchers from North Carolina State University and the University of Texas have developed and demonstrated a new approach for designing photonic devices. The new method enabled the team to control the direction and polarization of light from thin-film LEDs, overcoming the widely known obstacles of beam shaping that arise from their Lambertian nature. Such LEDs with directional and polarized light emission could be useful for many photonic applications.

'This is a fundamentally new device architecture for photonic devices,' says Franky So, corresponding author of a paper describing the work and Professor of Materials Science and Engineering at NC State. 'And we've demonstrated that, using our approach, directional and polarized emissions from an organic LED or a perovskite LED without external optical elements can be realized'.

Rice University scientists, in collaboration with a team from Los Alamos National Laboratory (LANL), have reported a technology that could dramatically reduce the cost of semiconductor electron sources, key components in various devices that range from night-vision goggles and low-light cameras to electron microscopes and particle accelerators.

Perovskite semiconductors (silver) treated with a layer of cesium (blue-green) could be tuned to emit free electrons (gray) over both visible and ultraviolet spectra (colored arrows), and a layer of cesium could regenerate degraded photocathodes.

Billions of dollars are spent each year on photocathode electron sources made from semiconductors containing rare elements like gallium, selenium, cadmium and tellurium. "This should be orders of magnitude lower in cost than what exists today in the market," said study co-corresponding author Aditya Mohite, a Rice materials scientist and chemical engineer. He said the halide perovskites have the potential to outperform existing semiconductor electron sources in several ways.

Researchers from the Shaanxi Normal University in China have designed a perovskite solar cell based on methylammonium lead iodide (MAPbI₃) through a dual passivation technique that simultaneously passivates trap defects in both the perovskite and electron transport layer (ETL) films.

'So far, most techniques for modifying perovskite solar cells focus on either the perovskite or electron transport layer,' the research group reported, noting that the ETL must have decent optical transmittance and high electron mobility to extract photo'induced carriers and contribute to the solar cell efficiency.