Illustration of the layers in a the perovskite solar cell and an image of a nanoribbon. Image: T.J. Macdonald and T. Webb.
Illustration of the layers in a the perovskite solar cell and an image of a nanoribbon. Image: T.J. Macdonald and T. Webb.

Phosphorene nanoribbons (PNRs) are ribbon-like strands of the 2D material phosphorene. Like graphene, phosphorene is made of single-atom-thick layers of atoms, but phosphorus atoms rather than carbon atoms. PNRs were first produced in 2019, and hundreds of theoretical studies have predicted how their properties could enhance all kinds of devices, including batteries, biomedical sensors and quantum computers.

However, none of these predicted exciting properties have so far been demonstrated in actual devices. Now, for the first time, a team led by researchers at Imperial College London and University College London in the UK has used PNRs to significantly improve the efficiency of a perovskite solar cell, demonstrating that the ‘wonder material’ may indeed live up to its hype. The researchers publish their findings in a paper in the Journal of the American Chemical Society.

“Hundreds of theoretical studies have foreseen the exciting properties of PNRs, but no published reports have yet demonstrated these properties, or their translation into improved device performance,” said lead researcher Thomas Macdonald from the Department of Chemistry and the Centre for Processable Electronics at Imperial.

“We are therefore delighted to not only provide the first experimental evidence of PNRs as a promising route for high-performance solar cells, but also showcase the versatility of this novel nanomaterial for use in next-generation optoelectronic devices.”

The team incorporated the PNRs into solar cells made from perovskites – a new class of materials that holds a great deal of promise, as scientists can easily change how they interact with light to suit a range of applications. Furthermore, unlike traditional inflexible silicon-based solar cells, perovskite solar cells can be made from liquid solutions, facilitating low-cost printing into thin, flexible films. Novel nanomaterials, such as PNRs, can be simply printed as an extra layer to improve device functionality and efficiency.

By including PNRs, the team was able to produce perovskite solar cells with an efficiency above 21%, on a par with traditional silicon solar cells. They were also able to experimentally verify just how PNRs are able to achieve this improved efficiency.

They showed that PNRs improve ‘hole mobility’. ‘Holes’ are the opposite partner of electrons in electrical transport, so improving their mobility (a measure of the speed at which they move through the material) helps electrical current move more efficiently between layers of the device. This experimental validation of the power of PNRs will help researchers create new design rules for optoelectronic devices.

“Our results show that the functional electronic properties of PNRs indeed translate to improved functionality,” said Macdonald. “This highlights the genuine importance and utility of this newly discovered nanomaterial and sets the benchmark for PNR-based optoelectronic devices.”

Further studies using PNRs in devices will allow researchers to discover more mechanisms for how they can improve performance. The team will also explore how modifying the surface of the nanoribbons could improve the unique electronic properties of the materials.

This story is adapted from material from Imperial College London, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.