Advancing Basic Science for Humanity
2008 Nanoscience Prize Explanatory Notes
The creation of new technologies through the manipulation of materials at the atomic level is widely predicted to revolutionize a wide range of industries in the near future. Announcements of advances in nanoscience are made almost weekly by scientists from across the world.
In making their award, the Kavli Nanoscience Prize Committee has selected two scientists without whose pioneering work subsequent developments with huge implications in the fields of energy, the environment, electronics, chemistry, composite materials and bio-medicine would have been impossible.
Louis E. Brus, of Columbia University in the US, made a fundamental discovery in 1983 while studying the optical properties of semiconductors whose atoms or molecules had been excited by the absorption of light.
Unlike traditional semiconductors such as silicon, Brus made water-based suspensions of tiny semiconductor particles and noticed that they took on unusual properties depending on their size and shape. Collaborating with colleagues, Brus made smaller and smaller synthetic particles and by the mid-1980s he realised these colloidal semiconductor nanocrystals, now commonly known as quantum dots, could prove highly useful in a variety of fields.
Quantum dots have a number of interesting and potentially useful properties. The colour of light they emit when under UV light varies according to their size. This and their long-term stability make them ideal for use as markers to study molecular interactions and changes in biological systems.
Whereas the organic dyes currently used to track the development of tumours or the precise mechanism of a drug in the body may last for only hours or days, quantum dots can remain useful for months or even years. As a result of Brus’ pioneering work hundreds of teams of scientists are investigating the use of quantum dots in medical applications such as early cancer identification, tumour imaging, and drug delivery.
Others are using them to develop computer displays that are more efficient and accurate alternatives to traditional models, and advanced, low cost photovoltaic cells with increased flexibility and efficiency.
Physicist Sumio Iijima, of Meijo University, Japan, is widely known as the scientist who discovered carbon nanotubes. These structures and their properties had been studied prior to his landmark publication in Nature 17 years ago; however his work triggered unprecedented interest and further research in the subject.
After attending a conference at which he discussed the recent discovery of novel forms of carbon with some of the pioneers in the field, Iijima returned to Japan to build on his previous work in the field. His Eureka moment came on June 23, 1991, while examining crushed soot formed as a result of applying an electric current to carbon rods. Peering down his microscope, he noticed the resulting carbon forms were arranged in needle-like tubular structures. Hexagons of carbon atoms formed spirals of varying pitch around the axis of each needle.
Iijima’s expertise in the use of electron microscopes helped in his detailed structural analysis of these nanotubes and allowed him to rapidly recognise a wide range of potential applications. They are many times stronger than steel at one sixth of the weight. Researchers have already exploited this to develop a prototype bullet-proof vest, and others are using them in composite materials to improve the strength and durability of everyday items as diverse as sports equipment and construction materials.
The electrical and thermal properties of nanotubes vary according to the way they are created and their diameter. Depending on their atomic structures they can have semiconducting or metallic properties, meaning they have potential uses in the production of conductive plastic films and electronic components such as diodes, transistors, electrodes.
Iijima has continued his research in nanotubes, learning how to manipulate them further and is working to harness their unique properties as hydrogen storage vessels in fuel-cell batteries.
Professor Arne Skjeltorp, of the University of Oslo, and chairman of the Kavli Nanoscience Prize Committee, said: “Nanoscience deals with the very building blocks of nature. The biological systems that surround us are full of nano-scale systems and components. In the course of the evolutionary process, nature has, over millions of years, developed numerous solutions for robustness and adaptability, including sophisticated mobility and self-healing mechanisms, highly sensitive sensors, and complex information and communication systems. Many leading scientists believe our urgent needs in the fields of energy, the environment, health and technology can be addressed by learning from nature. Brus and Iijima created prototype nanoscale building blocks in zero and one dimension, as ‘dots’ and ‘tubes’, in the chemistry and physics arenas. They both looked for and found something new along the long road towards creating our own version of smart biological solutions.”