Scientists grow 'sea urchin'-shaped structures

Jul 29, 2010
These are "sea urchins" made of tiny polystyrene balls, with zinc oxide nanowire "spines" are created using a simple electrochemical process. Credit: Empa

Swiss researchers have succeeded in growing sea-urchin shaped nanostructures from minute balls of polystyrene beads using a simple electrochemical process. The spines of the sea urchin consist of zinc oxide nanowires. The structured surface should help increasing the efficiency of photovoltaic devices.

Processes which lend materials new characteristics are generally complicated and therefore often rather difficult to reproduce. So surprise turns to astonishment when scientists report on new methods which not only produce outstanding results despite the fact that they use economically priced starting materials but also do not need expensive instrumentation.

Just a simple framework made of polystyrene

This is exactly what Jamil Elias and Laetitia Philippe of Empa's Mechanics of Materials and Nanostructures Laboratory in Thun have succeeded in doing. They used polystyrene spheres as a sort of scaffolding to create three-dimensional nanostructures of semiconducting zinc oxide on various substrates. The two scientists are convinced that the (nanostructured) "rough" but regularly-structured surfaces they have produced this way can be exploited in a range of electronic and optoelectronic devices such as and also short wave lasers, light emitting diodes and field emission displays.

The scientific world reacted promptly. The paper in which the results were reported was published in January 2010 in the on line edition of Advanced Materials. In the same month it became the most frequently downloaded article, and in April it was selected to appear on the Inside Front Cover of the journal.

The principle behind the process is quite simple. Little spheres of polystyrene a few micrometers in diameter are placed on an electrically conducting surface where they orient themselves in regular patterns. Polystyrene is cheap and ubiquitous - it is widely used as a packaging material (for example for plastic yoghurt pots) or as in expanded form as a solidified foam.

Hollow bodies with prickles for photovoltaic applications

The tiny balls of polystyrene anchored in this way form the template on which the nanowires are desposited. Jamil Elias has succeeded in using an electrochemical method which himself has developed to vary the conductivity and electrolytic properties of the polystyrene balls in such way that the zinc oxide is deposited on the surface of the microspheres. Over time regular nanowires grow from this surface, and when this process is complete the polystyrene is removed, leaving behind hollow spherical structures with spines - little sea-urchins, as it were! Tightly packed on the underlying substrate, the sea-urchins lend it a three-dimensional structure, thereby increasing considerably its surface area.

This nanostructured surface is predestined for use in photovoltaic applications. The researchers expect that it will have excellent light scattering properties. This means the surface will be able to absorb significantly more sunlight and therefore be able to convert radiated energy into electricity more efficiently. In a project supported by the Swiss Federal Office of Energy (SFOE), Laetitia Philippe and her research team are developing extremely thin absorbers (ETAs) for solar cells, based these .

Explore further: Thinnest feasible nano-membrane produced

More information: J. Elias, et al.: Hollow Urchin - like ZnO thin Films by Electrochemical Deposition, Advanced Materials, Volume 22, Issue 14, Pages 1607 - 1612 (April 12, 2010) DOI:10.1002/adma.200903098

Related Stories

Chemists measure copper levels in zinc oxide nanowires

Feb 19, 2008

Chemists at the National Institute of Standards and Technology have been the first to measure significant amounts of copper incorporated into zinc oxide (ZnO) nanowires during fabrication. The issue is important ...

Miniature Doughnuts

Mar 15, 2005

A matter of capillary action: colloid crystals as molds for nanorings It isn't only prospective bridal couples that are interested in rings; engineers and scientists are also fascinated by the apparently near-magical properti ...

Strength is shore thing for sea shell scientists

Mar 08, 2010

(PhysOrg.com) -- Scientists have made synthetic 'sea shells' from a mixture of chalk and polystyrene cups - and produced a tough new material that could make our homes and offices more durable.

Microbes convert 'Styrofoam' into biodegradable plastic

Feb 23, 2006

Bacteria could help transform a key component of disposable cups, plates and utensils into a useful eco-friendly plastic, significantly reducing the environmental impact of this ubiquitous, but difficult-to-recycle waste ...

Recommended for you

Thinnest feasible nano-membrane produced

Apr 17, 2014

A new nano-membrane made out of the 'super material' graphene is extremely light and breathable. Not only can this open the door to a new generation of functional waterproof clothing, but also to ultra-rapid filtration. The ...

Wiring up carbon-based electronics

Apr 17, 2014

Carbon-based nanostructures such as nanotubes, graphene sheets, and nanoribbons are unique building blocks showing versatile nanomechanical and nanoelectronic properties. These materials which are ordered ...

Making 'bucky-balls' in spin-out's sights

Apr 16, 2014

(Phys.org) —A new Oxford spin-out firm is targeting the difficult challenge of manufacturing fullerenes, known as 'bucky-balls' because of their spherical shape, a type of carbon nanomaterial which, like ...

User comments : 0

More news stories

'Exotic' material is like a switch when super thin

(Phys.org) —Ever-shrinking electronic devices could get down to atomic dimensions with the help of transition metal oxides, a class of materials that seems to have it all: superconductivity, magnetoresistance ...

Innovative strategy to facilitate organ repair

A significant breakthrough could revolutionize surgical practice and regenerative medicine. A team led by Ludwik Leibler from the Laboratoire Matière Molle et Chimie (CNRS/ESPCI Paris Tech) and Didier Letourneur ...

Treating depression in Parkinson's patients

A group of scientists from the University of Kentucky College of Medicine and the Sanders-Brown Center on Aging has found interesting new information in a study on depression and neuropsychological function in Parkinson's ...