Swansea team reaches record efficiency for roll-to-roll printed perovskite solar cells

A recent study reported the highest efficiency ever recorded for full roll-to-roll printed perovskite solar cells (PSCs), marking a significant step on the way to cheaper and more efficient ways of generating solar energy.

The team at Swansea University's SPECIFIC Innovation and Knowledge Center, led by Trystan Watson, reported using a roll-to-roll fabrication method for four layers of slot-die coated PSCs. The PSCs gave the stable power output of 12.2 percent - the highest efficiency recorded for four layers of roll-to-roll printed PSCs to date.

Printed coatings enable more efficient solar cells

Researchers at Cambridge’s Department of Materials Science and Metallurgy, working with Imperial College London and the Solar Energy Research Institute of Singapore, have developed a method to print ultrathin coatings on perovskite-based solar cells, allowing them to work in tandem with silicon solar cells to boost efficiencies.

New method to print ultrathin coatings to improve PSCs image

Solar cells work by absorbing sunlight to produce clean electricity. But photovoltaics can absorb only a fraction of the solar spectrum, which limits their efficiencies. The typical efficiency of a solar panel is only 18-20%.

Microscopic structures could improve the efficiency of perovskite solar cells

An international research team, led by Stefan Weber from the Max Planck Institute for Polymer Research in Mainz, has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell.

Clever alignment of these electron highways could make perovskite solar cells more efficient. When solar cells convert sunlight into electricity, the electrons of the material inside the cell absorb the energy of the light. The electrons excited by the sunlight are collected by special contacts on the top and bottom of the cell. However, if the electrons remain in the material for too long, they can lose their energy again. To minimize losses, they should therefore reach the contacts as quickly as possible. Microscopically small structures in the perovskites - so-called ferroelastic twin domains - could be helpful in this respect: They can influence how fast the electrons move.

New polymer-based hole transport layer to push forward perovskite-based flexible and wearable electronics

A team of researchers led by Nanchang University in China tested a polymer-based hole transport layer for flexible perovskite solar cells, using a glue to attach it to the active perovskite. The team was able to assemble the cells into a small flexible module suitable for wearable solar applications, and says its design was inspired by the structure and movements of human vertebrae.

Biomimetic mechanisms of the vertebrae and PSCs imageBio-inspired vertebral design for scalable and flexible perovskite solar cells. Image from Nature Communications

The team reported that the solar cell measured 1.01cm² and achieved a stabilized efficiency of 19.87%. The cell was tested for 3000 hours under one-sun illumination at room temperature and was shown to retain 85% of its initial efficiency.

Kyushu University team develops a surface treatment method for perovskite cells with reduced hysteresis

Researchers in Japan's Kyushu University have modified the tin(IV) oxide layer of a perovskite device with a fullerene-derivative-based self-assembled monolayer to produce a cell they claim offers stability and a reduction in the hysteresis effect which makes predicting power output so tricky.

The Kyushu University team has developed a surface treatment method for perovskite cell production they say reduces hysteresis – an effect which afflicts perovskite devices because their output depends on a variety of previous inputs rather than just their immediate condition, rendering performance less predictable. In perovskite cells, hysteresis is strictly dependent on the composition of the material. Ion migration and non-radiative recombination near interfaces are generally considered responsible for the effect.