The 2010 Millennium Grand Prize Winner Michael Grätzel is the father of third generation dye-sensitized solar cells. Grätzel cells, which promise electricity-generating windows and low-cost solar panels, have just made their debut in consumer products.

One of mankind’s greatest challenges is to find ways to replace the diminishing fossil fuel supply. The most obvious energy source is the sun, origin of almost all the energy found on Earth. The surface of the Earth receives solar radiation energy at an average of 81,000 terawatt – exceeding the whole global energy demand by a factor of 5,000. Yet, we are still figuring out a cost-effective way of harnessing it.

Solar cells, converting energy from the sun into electricity, were first used in the 1950s to power orbiting satellites and other spacecraft. Applied to power generation on Earth, the price does matter. Selected silicon based technology was – and still is – expensive, even if the cost of photovoltaics has declined steadily since the first solar cells were manufactured.

Grätzel’s innovation, the dye solar cell (DSC), is a third generation photovoltaic technology. The technology often described as ‘artificial photosynthesis’ is a promising alternative to standard silicon photovoltaics. It is made of low-cost materials and does not need an elaborate apparatus to manufacture. Though DSC cells are still in relatively early stages of development, they show great promise as an inexpensive alternative to costly silicon solar cells and an attractive candidate for a new renewable energy source.

The 2010 Millennium Technology Prize laureate Steve Furber is the principal designer of the ARM 32-bit RISC microprocessor, an innovation that revolutionised mobile electronics. The ingeniously designed processor enabled the development of cheap, powerful handheld, battery-operated devices. In the past 25 years nearly 20 billion ARM based chips have been manufactured.

You may never have heard of ARM microprocessors, but probably use at least one every day. They tick inside our mobile phones, mp3-players, video recorders and home routers. Today ARM technology is used in more than 98 percent of the world’s mobile handsets and over one-quarter of all electronic devices.

In 1985 Furber become the father of a microprocessor phenomenon – a single chip which did the same amount of work as other 32-bit microprocessors but used one tenth of their transistors – and consequently, one tenth of their electricity. Furber was the principal designer of the ARM 32 bit microprocessor at Acorn Computers.

The original design was simple and elegant. It exploited Reduced Instruction Set Computing (RISC) architecture. ARM was the world’s first commercially available RISC microprocessor. It was initially used in the Acorn Archimedes personal computer released in 1987.

The relative simplicity of ARM processors made them suitable for low power applications. It is this that has allowed them to dominate the mobile and embedded electronics market as relatively low cost and small microprocessors and microcontrollers.

Furber’s innovation has underpinned the rapid growth in mobile communications, which has opened up economic opportunities and enhanced the quality of life for billions in the developing and developed world.

Today about 98 percent of the more than one billion mobile phones sold each year use at least one ARM processor. The processors are also used extensively in other consumer electronics, including PDAs, digital media and music players, hand-held game consoles, calculators and computer peripherals such as hard drives and routers.

The 2010 Millennium Technology Prize Laureate Sir Richard Friend’s initial innovation, organic Light Emitting Diodes (LEDs), was a crucial milestone in plastic electronics. He showed a method to use polymers as solution processed semiconductors. Electronic paper, cheap organic solar cells and illuminating wall paper are examples of the revolutionary future products his work has made possible.

In electronic devices different materials have different functions. Traditional electronics rely on inorganic conductors such as copper and doped silicon. Copper wires conduct electricity; silicon semiconductor chips do the computing. Polymer plastics are generally insulators, blocking the passage of electrical current. They are an excellent choice for around wires to prevent short circuits, or to shape mobile phone covers. Or so traditional thinking would suggest.

Today many new phones have touch OLED screens. OLED stands for Organic Light Emitting Diode, made of conductive plastic material. The material is called “organic” because the polymers used are carbon-based, much like living organisms. Soon we may see 100 inch high-definition TV-sets, which are only few millimetres thick and can be rolled up when not in use, or paper-thin, inexpensive lighting panels covering the whole wall. Electronic components based on polymers have made these applications possible.

Friend’s inventions were landmark achievements in the rise of plastic electronics. In the late Eighties, his research group discovered that conjugated polymers behave in many respects like inorganic semiconductors and can be used in a number of semiconducting devices. Realising the significance of their discovery Richard Friend, Donal Bradley and Jeremy Burroughes filed a patent for polymer LED in April 1990.

Thanks to their pioneering discoveries, plastic electronics has now developed into a large international research field with significant academic and industrial activities. Polymer LEDs are already used in small displays, and energy-efficient lighting applications are being developed. Polymer photovoltaic diodes promise to enable very low cost solar cells. Printed polymer transistors enable new electronic applications such as flexible and transparent displays.

An important characteristic of plastic electronics is the simplicity of the method used to produce them. Inorganic transistors require massive vacuum systems and complex manufacturing processes. However, the organic polymer materials Friend used can be dissolved in organic solvents to create “inks” that can be used to create circuits simply by printing them under normal atmospheric conditions.

It is easy to understand the global electronics industry’s huge interest in organic and solution processable semiconductor technology. The ability to apply low temperature, low cost transistors and LEDs to flexible materials using a process that could be as simple as painting can enable new products that, until now, were unfeasible.

Dr. Robert Langer started his career working for a clinician named Judah Folkman. “He was trying to figure out a way to stop blood vessels growing into tumors and my work was to isolate substances that might stop the blood vessels growing into cancerous tumors.”

To do that, Langer had to identify such substances and also conduct a bioassay that would test the effects of these substances in the body by putting a material containing the substance into the body right next to a tumor. It had to last for at least a month, if not longer, and not cause any harm to the body.

“The only way I could think to do this was to create a polymer that would slowly release the different molecules I was isolating. And we were fortunate, after quite a long period of work, to develop a whole series of slow release polymers that could release medications to the body over time.”

Controlled drug release

In fact polymers were used to encase drug molecules even before Langer’s work, but the problem was the size of the new drug molecules: they were simply too big to go through the small holes in polymers and there was nothing one could do about it, Langer was advised.

So instead of changing the laws of nature, Langer turned the question upside down: rather than putting the drug molecules into polymer, he layered polymer around the molecules in a three dimensional matrix structure that allowed the molecules to pass through slowly. By changing the molecules and the polymer, he was now able to use all kinds of molecules and control their release almost as he wanted.

The properties of polymers can be also modified by external stimuli such as ultrasound, electric pulses or magnetic fields to change the release rate of the drug. This has led to the development of increasingly sophisticated release systems and, when combined with electronics on the micro chip, the release rate can be programmed in advance so that the chip delivers a carefully-measured dose of the medicine precisely when it’s needed. Langer’s team has also developed an implantable chip that can also monitor a patient’s blood chemistry and deliver medication accordingly.

Tissue regeneration

The polymer research led to the design of new kind of biomaterials that can be used as tissues. For example, emerging technologies enable the artificial production of skin, cartilage, liver or other cells. The idea behind tissue engineering is to make a temporary structure for the cells that can grow around and in within the polymer material. When the natural tissue is strong enough, the artificial “scaffold” dissolves.

Artificial skin is already in clinical trials and growing liver or pancreas organs from the patient’s own cells in may soon be a reality. Articifial tissues may soon help nerves to regenerate and thus help people who are paralyzed, too.

Dr. Langer’s research laboratory at MIT is the largest biomedical engineering lab in the world. And while the man himself can still be seen in the lab, now he is mainly guiding his more than 100 researchers.

“I mainly spend time thinking and trying to find the best directions for the research. I like also teaching, which I find very rewarding and stimulating, so I teach almost daily. Research is a long term undertaking, but teaching is very immediate – you can see right away that your students are learning.”

From research to business

Dr. Langer has co-founded several small companies that have commercialized his ideas. The first, Enzytech, specialized in drug delivery and the use of enzyme and protein-based technologies in food additives.

Other notable companies are Mimeon, a company that focused on glycomics, the study of carbohydrates used for drug discovery, and MicroChips, a startup that is commercializing microchip drug delivery technology. Many of Langer’s patented inventions have been licensed and are being used globally.

The principle behind the optical fibre amplifier is quite simple: take some optical fibre that incorporates optical material with special properties and, using a laser, target light on it. Optical amplifiers can also be considered to be lasers without the feedback. While a laser’s purpose is to generate coherent light; the optical amplifier boosts the actual quantity of light transmitted.

Physically, optical amplifiers are just a laser source (i.e. a laser diode or an array of laser diodes) and can be regarded as specially-doped optical fibre, reeled into a coil with the optical isolators and filters required to shepherd the light. For scientists the challenge was a threefold one: finding the right doping material, incorporating it into the fibre and constructing a suitable pump laser.

Amplification

The basic principle behind optical amplification has been known since the era of Albert Einstein. When certain dopant ions in a material are targeted using an intense laser source, their energy state jumps from lower (ground) to higher (excited). The ions spontaneously drop back to ground state by emitting the extra energy as a photon (or light quanta) that corresponds to the energy difference in levels.

When the correct energy levels are used, photons emitted by the dopant ions have the same wavelength as the signal light that needs to be amplified. If this signal is input to the medium then the excited ions are forced to release their emery by stimulated emission. The resulting output signal is therefore more powerful than the input signal. Amplification thus results from the stimulated emission of photons from dopant ions in the doped fibre. The dopant ions are maintained in the excited state by a pump laser, which creates an energy reservoir for the amplification process.

Erbium

Erbium (Er) is a chemical element with an atomic number of 68, making it one of the heaviest elements in the periodic table before the line of radioactive metals. Discovered by Carl Gustaf Mosander in 1843 in Ytterby, Sweden, the salts of this rare earth metal are rose-colored (which is used in artistic glassware). Apart from optical telecommunications, the 1.55 microns laser wavelength of erbium ions is has the “eye-safe” property, which allows many non-hazardous applications such as telemetry, laser imaging, and surgery for skin, eye and ear.

When the core of a silica fibre is doped with trivalent Erbium ions (Er+3) and is efficiently pumped with a laser at either 980 nm or 1480 nm, it exhibits gain in the 1550 nm region. Erbium was perfect for silica-based optical fibre communications, because standard single-mode optical fibres have minimal loss at wavelengths of 1525–1565 nm. Erbium also works very well at 1570-1610 nm, another widely-used transmission window.

The most recent version of the optical amplifier is the Raman amplifier, in which the coil of erbium-doped fibre can be much shorter than in a traditional Erbium amplifier. At 500 mW or more than 1 W of optical power, the pumping power required for Raman amplification is higher than that required by the traditional Erbium amplifiers. The principal advantage of Raman amplification is its ability to provide distributed amplification within the transmission fibre, thereby increasing the spans between amplifier and regeneration sites.

Viterbi’s innovation is the Viterbi algorithm, the mathematical formula that enables clear and practically error-free radio communication over long distances, from moving low power transmitters and receivers. The algorithm was published in 1967

Teaching signal processing was difficult due to the complicated nature of the algorithms used, so Viterbi formulated a more simple way to explain the processing techniques. After realizing the importance of this algorithm, he submitted an article to the IEEE Transactions on Information Theory: “Error bounds for convolutional codes and an asymptotically optimum decoding algorithm”.

The paper was published in 1967 but the algorithm was considered not much more than elegant theoretical work until computing technology became powerful enough to handle the massive calculations needed to apply the work. Thus the Viterbi algorithm didn’t find widespread application until the move to digital and wireless communications. At that time nobody could imagine a general application for the algorithm, so Viterbi followed his lawyer’s advice and did not patent it.

What is Viterbi algorithm?

The algorithm is essentially just a fast way of eliminating dead ends in the communication. The principle is simple, but the algorithm itself requires considerable computing power. Each bit in the digital information – 0 or 1 – has to be represented by four, eight or more code symbols. So, additional “redundant” information is added at the transmitter, in a process called error correction coding. The result coming into a receiver is a pulsing, miscellaneous stream of bits, ones and zeros.

The received signal is not a clear chain of zeros and ones but is code symbols from which the actual information bits can be reconstructed. Some individual bits can be dropped or distorted, because with the code symbols the missing bits can be guessed with high confidence. There are four states of ‘guess’: very sure, moderately sure, sort of sure and barely sure. The decoder in the receiver evaluates the certainty by comparing the result with neighboring bits and makes the best possible guess. The result is a clear, practically- undamaged message. The key is in a time series of incoming information, with each set of bits tagged in order of arrival.

The algorithm makes it possible to spread a carrier frequency over a wide area of the electromagnetic spectrum. Thousands of low emitting power transmitters can operate in same band range at the same time in small areas without interfering with each other, because their carrier frequencies are coded with different patterns. This principle was first used in military communications and is now the basis of the code division multiple access (CDMA) and UMTS digital cellular communications.

From 1967 to the 21st century

At the time that Dr. Viterbi published his algorithm, computers were not powerful enough to make all calculations required for decoding in real time, but with the growth in computing power, the Viterbi algorithm revolutionized the telecommunications environment by providing a useful tool for error-free communications.

The birth of the DNA fingerprinting can be pinpointed exactly to the morning of September 10th, 1984. It was then that Jeffreys had a “eureka” moment” in his Leicester lab while examining an X-ray that formed part of a DNA experiment regarding genetic markers for inheritance patterns of illness.But what the experiment showed, unexpectedly, were the similarities and differences in his technician’s family’s DNA. Jeffreys quickly realized the import of this discovery of a biological identification mechanism. “That moment changed my life,” he says. And it led to the development of techniques that would fundamentally change this important area of science.

How to make a DNA fingerprint?

The first step is to extract DNA from the cells in a sample of blood, saliva, semen or other appropriate fluid or tissue. The traditional way to fingerprint DNA is by doing what is called a Southern blot. The DNA being analyzed must be separated from other material, cut into a few different-sized pieces using restriction enzymes, which are proteins that can cut double-stranded DNA without damaging the bases. Different length minisatellite alleles give differently-sized DNA fragments and can therefore be sized and compared by measuring the lengths of these fragments.

After this the DNA fragments are transferred from the fragile gel to a strong sheet of nylon or nitrocellulose paper membrane. The gel is discarded and the DNA is ready to be analyzed using a radioactive probe in a hybridization reaction by DNA polymerase.

A piece of X-ray film is exposed to the membrane after radioactive probing and fragments that have bound to the probe appear as black bands when the X-ray film is developed.

By measuring how far the fragments have moved through the gel one can calculate their sizes and therefore obtain the lengths of the different alleles. If one is checking family relationships, for example, one can see if a child has alleles the same size as one of those of either parent.

DNA fingerprinting evolves

The original method of DNA fingerprinting was slow and required large quantities of quality DNA, while the new methods use smaller amounts of DNA and samples that may also be more degraded than those previously used.

DNA fingerprinting took a huge leap forward with the invention of the polymerase chain reaction. Both discriminating power and ability to recover information from very small initial samples was now possible by amplification of specific regions of DNA using a cycling of temperature and a thermostable polymerase enzyme along with fluorescently-labelled sequence-specific primers of DNA.

Recent innovations have included the creation of primers targeting polymorphic regions on the Y-chromosome, which allows resolution of multiple male profiles, or for cases in which a differential extraction is not possible. Y-chromosomes are paternally-inherited, so analysis can help in the identification of paternally-related males

The potential of light-emitting diodes has been recognized since their invention in the early 1960s. LEDs emit no heat, use little energy and last for a very long time. But despite decades of effort, nobody could make LEDs that would emit bright blue light, the pivotal component required to make useful white light LEDs.

In 1993 Shuji Nakamura astonished the scientific community with the first successful blue LED. This was the final step in creating a brilliant white LED.

The choice of gallium nitride

Different semiconductor materials produce different colours. Unlike thousands of other researchers, Nakamura decided to work with gallium nitride (GaN).

Speaking about his innovation, Nakamura says: “At that time, in 1989, there were two materials for making blue LEDs: zinc selenide and gallium nitride. Everybody was working on zinc selenide because that was supposed to be much better. I thought about my past experience: if there’s a lot of competition, I cannot win. Only a small number of people at a few universities were working with gallium nitride so I figured I’d better work with that.”

In actual fact, Nakamura’s biggest breakthrough was the invention of Two-Flow MOCVD, a unique method (Two-Flow MOCVD) for fabricating GaN film with good crystal quality and uniform thickness.

World record quality

Nakamura: “In 1991 I succeeded in making the highest quality of gallium nitride crystals in the world. Another big breakthrough was making the first single crystal of indium gallium nitride, which we needed for an emitting layer. Finally at the end of 1993, I succeeded in making the first commercial based blue LEDs.”

Nakamura’s next step was to add a novel phosphor to his blue chip to obtain white light. In the mid-1990s, when Nakamura was using his blue LEDs to make white LEDs, he was also adapting his blue LED technology to make a blue laser.

Professor Nakamura’s current research interests are the growing of optoelectronic materials and the fabrication of novel semiconductor devices. He is working on full-colour LEDs, an efficient white-LED light bulb, laser diodes and high-power, microwave communication devices.

The World Wide Web became available to the public in 1991. It is now an irreplaceable tool for all Internet users.Tim Berners-Lee has had a goal since the creation of the Web of making the core Web technologies available at no cost.

“The decision to make the Web an open system was necessary for it to be universal. Had the technology been proprietary it would probably not have taken off. You can’t propose that something be a universal space and at the same time keep control of it.”

What is the Web?

The Web is a system of interlinked hypertext documents accessed via the Internet, a world-wide communications infrastructure developed for the robust transfer of information in the 1960s and 1970s.

The Web is one of many Internet-based communication services. Other computer software that uses the Internet includes electronic mail and entertainment applications such as games.

Several interdependent innovations

The first server and Web browser/editor software provided the foundation for the Web. Berners-Lee also produced first versions of the HTTP protocol, HTML language and URIs (Unique Resource Identifiers, sometimes called URLs). These allow Web users to access information in a variety of formats using just one program (a web browser).

Prior to the invention of the Web, exchanging information was more complex because people had to know lots of details about specific systems. The Web hid those details and provided a single interface for interacting with any type of of underlying hardware or system.

The Web also showed the true potential of hyperlinks. Quick browsing allows readers to escape from the fixed, sequential organisation of information.

The future

Berners-Lee believes that the future of the Web lies in the creation of a so-called “Semantic” Web. Currently, Web pages are designed to be read by humans. The Semantic Web is about marking data so that the testing of relationships between different datasets can be automated.

A Semantic Web could hand routine tasks over to machines, making the finding, sharing and integration of information much easier. Vast resources of information could then be used in much more efficient ways, allowing people to engage in more creative activities.