On this basis, they proposed the catalytic surface atmospheric pressure chemical vapor deposition method with gold as growth substrate,which achieved the high quality, single uniform and large-area films preparation of millimeter-sized WS2 single crystals. The study found that the catalytic activity of gold and low solubility of tungsten in gold ensure the growth of uniform monolayer high quality WS2 crystals. In the meanwhile, the electrochemical bubbling method may be applied in realization of WS2 high quality transfer without gold substrate damaging. The single WS2 obtained by this method has high crystalline quality, showing optical and electrical properties compared with the material prepared by mechanical exfoliation of the proposed.

 

In addition, the research proposed non-destructive method of roll-to-roll and electrochemical bubbling combination for transferring, which achieve a low-cost continuous transfer of large-area single WS2 film to flexible transparent substrate, which also realize the preparation of large-area flexible transparent WS2 monolayer’s thin films transistors array and the electrical properties is still not attenuated after being bent hundreds of times .

The journal Nature Communications recently published online the results of the RenWencai study group of Institute of Metal Research, the research realize the low-cost and large-area preparation of high-quality uniform strict monolayer tungsten disulfide (WS2) single crystal and thin films, which laid the material foundation on the applications of its flexible electronic / optoelectronic devices and valley electronics and spin electronics field.

 

The researchers found that gold is the only metal that does not react with sulphur and generate sulfide at a high temperature and have a catalytic activity, which can effectively reduce the barrier of tungsten trioxide vulcanization process, and tungsten atoms in gold have a extremely low solubility at high temperature.

With the development of economy and technology, the traditional tungsten wire light bulbs due to poor energy efficiency, in the trend of environmental protection, to be more energy-efficient LED bulbs and compact fluorescent lamps replaced. But the LED bulbs and compact fluorescent lamps issued a "cool white" light becomes brighter and slow process, a lot of people miss the days of tungsten wire light bulbs. According to reports, the US Massachusetts Institute of Technology (MIT) recently developed improved methods of tungsten wire light bulbs, the filament is surrounded with a special crystal structure, greatly reduce energy consumption which makes tungsten wire light bulbs more energy efficient than LED light bulbs and compact fluorescent lamps.

 

Tungsten wire light bulbs through the resistor and energized heated the finer tungsten to about 2700 ℃, allowed to issue glowing light, but in the whole process, 95% of the energy is converted to heat dissipation, so that the energy efficiency of tungsten wire light bulbs only 5%, compared to, LED bulbs and compact fluorescent lamps as the light energy can reach to 14%. It is for this reason that in 2012 prompted the EU comprehensive ban tungsten wire light bulbs.

 

To solve this problem, MIT scientists have developed with a special crystal structure surrounds the filament, and it will take the heat and trap the ultra-red radiation can let visible light through. The researchers believe this can make tungsten wire light bulbs energy efficiency reached 40%.

 

UK Energy Saving Trust data shows that if the general household use 60W traditional tungsten wire light bulbs, it takes 7.64 pounds per year (about 72.68 RMB), if using CFLs or LED bulbs, just 1.53, or 1.27 pounds per year respectively ( 14.55 or about RMB 12 RMB), but if the new improved tungsten wire light bulbs can really achieve the desired efficiency, it costs only 50 pence a year.