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.
Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously
17.01.2017 | Sonderforschungsbereich 668
Manchester scientists tie the tightest knot ever achieved
13.01.2017 | University of Manchester
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Materials Sciences
17.01.2017 | Architecture and Construction