China, Global Leader In NanoScience

Mobile phones, computers, cosmetics, bicyclesnanoscience is hiding in so many everyday items, wielding a huge influence on our lives at a microscale level. Scientists and engineers from around the world exchanged new findings and perceptions on nanotechnology at the recent 7th International Conference on Nanoscience and Technology (ChinaNANO 2017) in Beijing last week. China has become a nanotechnology powerhouse, according to a report released at the conference. China’s applied nanoscience research and the industrialization of nanotechnology have been developing steadily, with the number of nano-related patent applications ranking among the top in the world.

According to Bai Chunli, president of the Chinese Academy of Sciences (CAS), China faces new opportunities for nanoscience research and development as it builds the National Center for Nanoscience and Technology  (NCNST) and globally influential national science centers.

We will strengthen the strategic landscape and top-down design for developing nanoscience, which will contribute greatly to the country’s economy and society,” said Bai.

Nanoscience can be defined as the study of the interaction, composition, properties and manufacturing methods of materials at a nanometer scale. At such tiny scales, the physical, chemical and biological properties of materials are different from those at larger scales — often profoundly so.

For example, alloys that are weak or brittle become strong and ductile; compounds that are chemically inert become powerful catalysts. It is estimated that there are more than 1,600 nanotechnology-based consumer products on the market, including lightweight but sturdy tennis rackets, bicycles, suitcases, automobile parts and rechargeable batteries. Nanomaterials are used in hairdryers or straighteners to make them lighter and more durable. The secret of how sunscreens protect skin from sunburn lies in the nanometer-scale titanium dioxide or zinc oxide they contain.

In 2016, the world’s first one-nanometer transistor was created. It was made from carbon nanotubes and molybdenum disulphide, rather than silicon.
Carbon nanotubes or silver nanowires enable touch screens on computers and televisions to be flexible, said Zhu Xing, chief scientist (CNST). Nanotechnology is also having an increasing impact on healthcare, with progress in drug delivery, biomaterials, imaging, diagnostics, active implants and other therapeutic applications. The biggest current concern is the health threats of nanoparticles, which can easily enter body via airways or skin. Construction workers exposed to nanopollutants face increased health risks.

The report was co-produced by Springer Nature, National Center for Nanoscience and Technology (NCNST) and the National Science Library of the Chinese Academy of Sciences (CAS).


Chinese Quantum Satellite Sends ‘Unbreakable’ Code

China has sent an “unbreakablecode from a satellite to the Earth, marking the first time space-to-ground quantum key distribution technology has been realized, state media said. China launched the world’s first quantum satellite last August, to help establish “hack proofcommunications, a development the Pentagon has called a “notable advance“. The official Xinhua news agency said the latest experiment was published in the journal Nature, where reviewers called it a “milestone“.

The satellite sent quantum keys to ground stations in China between 645 km (400 miles) and 1,200 km (745 miles) away at a transmission rate up to 20 orders of magnitude more efficient than an optical fiber, Xinhua cited Pan Jianwei, lead scientist on the experiment from the state-run Chinese Academy of Sciences, as saying.

That, for instance, can meet the demand of making an absolute safe phone call or transmitting a large amount of bank data,” Pan said. Any attempt to eavesdrop on the quantum channel would introduce detectable disturbances to the system, Pan said. “Once intercepted or measured, the quantum state of the key will change, and the information being intercepted will self-destruct,” Xinhua said.

The news agency said there were “enormous prospects” for applying this new generation of communications in defense and finance.


How To Scavenge Simultaneously Solar And Wind Energy

To realize the sustainable energy supply in a smart city, it is essential to maximize energy scavenging from the city environments for achieving the self-powered functions of some intelligent devices and sensors.

solar and wind powered houseAlthough the solar energy can be well harvested by using existing technologies, the large amounts of wasted wind energy in the city cannot be eectively utilized since conventional wind turbine generators can only be installed in remote areas due to their large volumes and safety issues.
Here, the researchers from the Chinese Academy of Sciences rationally design a hybridized nanogenerator, including a solar cell (SC) and a triboelectric nanogenerator (TENG), that can individually/simultaneously scavenge solar and wind energies, which can be extensively installed on the roofs of the city buildings. Under the same device area of about 120 mm × 22 mm, the SC can deliver a largest outputpower of about 8 mW, while the output power of the TENG can be up to 26 mW. Impedance matching between the SC and TENG has been achieved by using a transformer to decrease the impedance of the TENG. The hybridized nanogenerator has a larger output current and a better charging performance than that of the individual SC or TENG.
This research presents a feasible approach to maximize solar and wind energies scavenging from the city environments with the aim to realize some self-powered functions in smart city.


Polymer Solar Cells, Low-Cost Alternative To Silicon

Polymer solar cells could be even cheaper and more reliable thanks to a breakthrough by researchers at Linköping University (Sweden) and the Chinese Academy of Sciences (CAS). This work is about avoiding costly and unstable fullerenes. In recent years, polymer solar cells have emerged as a low cost alternative to silicon solar cells. In order to obtain high efficiency, fullerenes are usually required in polymer solar cells to separate charge carriers. However, fullerenes are unstable under illumination, and form large crystals at high temperatures.

Now, a team of chemists led by Professor Jianhui Hou at the CAS has set a new world record for fullerene-free polymer solar cells by developing a unique combination of a polymer called PBDB-T and a small molecule called ITIC. With this combination, the sun’s energy is converted with an efficiency of 11%, a value that strikes most solar cells with fullerenes, and all without fullerenes. Feng Gao, together with his colleagues Olle Inganäs and Deping Qian at Linköping University, have characterized the loss spectroscopy of photovoltage (Voc), a key figure for solar cells, and proposed approaches to further improving the device performance.


We have demonstrated that it is possible to achieve high efficiency without using fullerene, and that such solar cells are also highly stable to heat. Because solar cells are working under constant solar radiation, good thermal stability is very important,” says Feng Gao, a physicist at the Department of Physics, Chemistry and Biology, Linköping University.

The combination of high efficiency and good thermal stability suggests that polymer solar cells, which can be easily manufactured using low-cost roll-to-roll printing technology, now come a step closer to commercialization,” says Feng Gao.
The results have been published in the journal Advanced Materials.


New Cheap Catalyst To Produce Hydrogen From Water

Graphene doped with nitrogen and augmented with cobalt atoms has proven to be an effective, durable catalyst for the production of hydrogen from water, according to scientists at Rice University. The Rice lab of chemist James Tour and colleagues at the Chinese Academy of Sciences, the University of Texas at San Antonio and the University of Houston have reported the development of a robust, solid-state catalyst that shows promise to replace expensive platinum for hydrogen generation.

Tucson fuel cell

Catalysts can split water into its constituent hydrogen and oxygen atoms, a process required for fuel cells. Hydrogen electric cars as the Tucson from Hyundai are powered by fuel cells.
The latest discovery, detailed in Nature Communications, is a significant step toward lower-cost catalysts for energy production, according to the researchers.

What’s unique about this paper is that we show not the use of metal particles, not the use of metal nanoparticles, but the use of atoms,” Tour said. “The particles doing this chemistry are as small as you can possibly get.
We’re getting away with very little cobalt to make a catalyst that nearly matches the best platinum catalysts.” In comparison tests, he said the new material nearly matched platinum’s efficiency to begin reacting at a low onset voltage, the amount of electricity it needs to begin separating water into hydrogen and oxygen.


How To Increase Solar Cells Efficiency by 30%

Researchers from North Carolina State University and the Chinese Academy of Sciences have found an easy way to modify the molecular structure of a polymer commonly used in solar cells. Their modification can increase solar cell efficiency by more than 30 percent.

Polymer-based solar cells have two domains, consisting of an electron acceptor and an electron donor material. Excitons are the energy particles created by solar cells when light is absorbed. In order to be harnessed effectively as an energy source, excitons must be able to travel quickly to the interface of the donor and acceptor domains and retain as much of the light’s energy as possible.

solar cell in one molecule
The possible drawback in changing the molecular structure of these materials is that you may enhance one aspect of the solar cell but inadvertently create unintended consequences in devices that defeat the initial intent,” according to NC State physicist and co-author Harald Ade. “In this case, we have found a chemically easy way to change the electronic structure and enhance device efficiency by capturing a lager fraction of the light’s energy, without changing the material’s ability to absorb, create and transport energy.

The researchers’ findings appear in Advanced Materials.


Toward The First Molecular Integrated Circuit

A molecular integrated circuit was created by a group of chemists and physicists from the Department of Chemistry Nano-Science Center at the University of Copenhagen – Denmark – and Chinese Academy of Sciences, Beijing. The breakthrough was made possible through an innovative use of the two dimensional carbon material graphene. Kasper Nørgaard is an associate professor in chemistry at the University of Copenhagen. He believes that the first advantage of the newly developed graphene chip will be to ease the testing of coming molecular electronic components. But he is also confident, that it represents a first step towards proper integrated molecular circuits.

molecular electronics

Graphene has some very interesting properties, which cannot be matched by any other material. What we have shown for the first time is that it’s possible to integrate a functional component on a graphene chip. I honestly feel this is front page news”, says Nørgaard.

The discovery “Ultrathin Reduced Graphene Oxide Films as Transparent Top-Contacts for Light Switchable Solid-State Molecular Junctions” has just been published online in the periodical Advanced Materials.