Sticky tape & phosphorus the key to ultrathin solar cells

Sticky tape & phosphorus the key to ultrathin solar cells: ANU media release
This is Jiajie Pei with crystals of black phosphorus. Credit: Stuart Hay, ANU

Scientists studying thin layers of phosphorus have found surprising properties that could open the door to ultrathin and ultralight solar cells and LEDs.

The team used to create single-atom thick layers, termed phosphorene, in the same simple way as the Nobel-prize winning discovery of graphene.

Unlike graphene, phosphorene is a semiconductor, like , which is the basis of current electronics technology.

"Because phosphorene is so thin and light, it creates possibilities for making lots of interesting devices, such as LEDs or ," said lead researcher Dr Yuerui (Larry) Lu, from The Australian National University (ANU).

"It shows very promising light emission properties."

The team created phosphorene by repeatedly using sticky tape to peel thinner and thinner layers of crystals from the black crystalline form of phosphorus.

As well as creating much thinner and lighter semiconductors than silicon, phosphorene has light emission properties that vary widely with the thickness of the layers, which enables much more flexibility for manufacturing.

"This property has never been reported before in any other material," said Dr Lu, from ANU College of Engineering and Computer Science, whose study is published in the Nature serial journal Light: Science and Applications.

"By changing the number of layers we can tightly control the band gap, which determines the material's properties, such as the colour of LED it would make.

This is an interview with Dr Lu and a demonstration of how to make phosphorene. Credit: ANU multimedia.
"You can see quite clearly under the microscope the different colours of the sample, which tells you how many layers are there," said Dr Lu.

Dr Lu's team found the optical gap for monolayer phosphorene was 1.75 , corresponding to red light of a wavelength of 700 nanometers. As more layers were added, the optical gap decreased. For instance, for five layers, the optical gap value was 0.8 electron volts, a infrared wavelength of 1550 nanometres. For very thick layers, the value was around 0.3 electron volts, a mid-infrared wavelength of around 3.5 microns.

The behaviour of phosphorene in thin layers is superior to silicon, said Dr Lu.

"Phosphorene's surface states are minimised, unlike silicon, whose surface states are serious and prevent it being used in such a thin state."


Explore further

Research team finds a way to produce black phosphorus in bulk

Journal information: Light: Science & Applications

Citation: Sticky tape & phosphorus the key to ultrathin solar cells (2015, July 20) retrieved 20 May 2019 from https://phys.org/news/2015-07-sticky-tape-phosphorus-key-ultrathin.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
100 shares

Feedback to editors

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more