The invisibility cloak & Metamaterial-enhanced solar cells

The invisibility cloak

Amrita Ghosh & Arya Mehta

So far, the most popular application of metamaterials being worked on is the ‘invisibility cloak’. This idea was first proposed by Professor Sir John Pendry. His team received a grant of £4.9 million to develop metamaterials for ‘invisibility cloaks’ in 2009.

The aim of this cloak is to use metamaterials to grab light and conceal it, therefore making it invisible to the human eye. This idea is based on the same principle as how water in a river flows around a stick – in this case the invisibility cloak is the stick preventing reflection of the object hidden (e.g. water), making it undetectable to the eye.

This research does not mean that Harry Potter fans can have a new addition to their ‘wizard collection’ for Christmas, but instead it may hold great promises for biomedical and military applications. This design could protect areas against radiotherapy for instance, or it could be used as a new strategy for camouflage.

The potential of the ‘invisibility cloak’ is unimaginable, and it only emphasises the creative uses of metamaterials. Progression in this field could generate a new era of technology and gadgets!

Metamaterial-enhanced solar cells

Emma Wills

A newly developed layer of tiny Aluminium studs has been found to enhance the efficiency of solar cells by up to 22%.

The coating, made up of cylinders just a hundred nanometres across, was investigated by scientists at Imperial College as part of an international collaboration.

They looked at similar structures in gold, silver and aluminium, to see which could scatter the incident light at a high enough angle without absorbing too much itself.

The scattered light takes a longer path through the solar cell, which can then extract more of its energy. This increase in efficiency looks to make the price of solar cells more competitive with fossil fuels in the future.

“As the absorbing material alone can make up half the cost of a solar panel our aim has been to reduce to a minimum the amount that is needed,” lead author of the research Dr. Nicholas Hylton said. For thinner solar cells in particular this is good news as they are already cheaper than traditional, thicker solar cells, but the thinness of their light-absorbing material means that they are too inefficient to be widely used.

This new coating could mean lightweight, flexible solar cells that could power laptops and other everyday devices.