Scientists from Singapore’s Institute of Materials Research and Engineering (IMRE) and National University of Singapore (NUS) have created a new chemical method that enables the development of a variety of tiny light conducting metal-semiconductor contacts. These light-sensitive nano-sized components could help create bioimaging labels as well as better photocatalysts used in fuel cells.
Metal-semiconductor ‘matchstick-like’ structures viewed under high-powered transmission electron microscopy. Copyright : IMRE
1. Sticking a ball onto a small pole might seem simple but try doing that at a scale a billion times smaller. Researchers have been making ‘matchstick-like’ nano-sized metal ball-semiconductor pole features with light-sensitive properties for some time but with great difficulty and strict limitations on the type of metals that can be used. The ‘matchstick-like’ shape is used because the ends of a semiconductor pole have been found to be more chemically reactive compared to other shapes thus allowing metals to be deposited easier. Scientists from IMRE and NUS have recently discovered a chemical process that is not only simpler to perform but greatly expands the range of different metals that can be coupled with the semiconductors. This opens the way for nano-sized structures with enhanced photoconductive properties or with entirely new functions. For example, the new nanostructures chemically synthesised by the researchers may be further developed as labels for enhanced bio-imaging applications such as magnetic resonance imaging (MRI), fluorescence and dark field imaging.
2. Referring to the possibility of the nanostructures being used to enhance current bioimaging techniques, Dr Chan Yin Thai, an IMRE scientist, explained, “The breakthrough may allow multiple imaging modes to be supported by a single label, which can significantly improve current imaging capabilities and give rise to powerful diagnostic tools”.
3. The light-sensitive metal-semiconductor pole features also have intrinsically good photocatalytic properties, where chemical reactions are triggered by light. For the moment, the researchers are looking at using the new method to produce materials that have ‘green’ photocatalytic applications, for instance, materials that enhance water-splitting to produce hydrogen more efficiently for fuel cells; and materials that actively degrade environmental pollutants on exposed surfaces like buildings and cars.
4. “The development of metal-semiconductor nanostructures for use in devices is still in its infancy but having access to a large variety of different metals really opens doors to a vast number of possibilities for scientific exploration and is a crucial milestone for ensuring continued R&D,” Dr Chan explained.
5. The scientists used a novel approach to develop the new method – by exploiting the light-sensitive properties of the semiconductor ‘pole’. By putting gold particles onto the ‘pole’ and then treating it with UV light, the IMRE and NUS scientists discovered that this made it easier to attach a greater variety of metals, using only mild chemicals. Before the success of this research, the metals that could be used for the ‘ball’ were limited. The chemicals needed in conventional treatment had to be mild so that it would not degrade the semiconductor ‘pole’. The degradation of the ‘pole’ would affect the photocatalytic properties of the structure. This limited the variety of metals that could be used as tougher metals could not be fixed onto the ‘pole’ using the mild chemicals.
6. The research paper, “Light-Induced Selective Deposition of Metals on Gold-Tipped CdSe-Seeded CdS Nanorods” was recently published in the well-known Journal of the American Chemical Society.
For media enquiries, please contact:Mr Eugene Low
About the Agency for Science, Technology and Research (A*STAR)
The Agency for Science, Technology and Research (A*STAR) is the lead agency for fostering world-class scientific research and talent for a vibrant knowledge-based and innovation-driven Singapore. A*STAR oversees 14 biomedical sciences and physical sciences and engineering research institutes, and six consortia & centres, located in Biopolis and Fusionopolis as well as their immediate vicinity. A*STAR supports Singapore's key economic clusters by providing intellectual, human and industrial capital to its partners in industry. It also supports extramural research in the universities, hospitals, research centres, and with other local and international partners. For more information about A*STAR, please see the links below.
Journalists can request copies of the research paper from r.bisson(at)researchsea.com.
ADIR Project: Lasers Recover Valuable Materials
21.07.2017 | Fraunhofer-Institut für Lasertechnik ILT
High-tech sensing illuminates concrete stress testing
20.07.2017 | University of Leeds
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....
A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...
Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision
Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...
21.07.2017 | Event News
19.07.2017 | Event News
12.07.2017 | Event News
21.07.2017 | Earth Sciences
21.07.2017 | Power and Electrical Engineering
21.07.2017 | Physics and Astronomy