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A new semiconductor nanofiber can greatly increase the efficiency of solar cells

The high performance nanomaterial has a wide range of applications. When used in air purifiers, it provides the agraphene superhighway…

The high performance nanomaterial has a wide range of applications. When used in air purifiers, it provides the agraphene superhighway for faster electron transport, which allows for more efficient contamination. Credit: nobeastsofierce | 1


A team from Hong Kong Polytechnic University (PolyU) developed a new nanostructure embedded in a semiconductor nanofibre that results in excellent conductivity. The nanocomposite addresses a conductivity conductivity inhibitor, with potential to improve a wide range of applications, from batteries and solar cells to air purifiers.

While semiconductors are used to a large extent, their efficiency has been limited by the natural process of photogenerated electrons in recombination with “holes” or potential electron support points. This reduces the moving current of electrons generated by light or external current and as a consequence reduces the efficiency of the device. PolyU’s Department of Mechanical Engineering designed a composite nanofibre that essentially provides a dedicated electrical transmission control when generated, eliminating the problem of recombination of electron holes.

The innovation was awarded the gold medal with the jubilee’s congratulations on the 45th International Exhibition of Inventions of Geneva in 2017.

The team avoided recombination by introducing a strong conductive nanostructure made of carbon nanotubes and the graph in a composition of titanium dioxide (TiO ] 2 ). The electrons and charges can be transported efficiently in the graph nucleus as soon as they are formed before being combined with the “holes” of the nanofibes. Led by Wallace Leung, the team has tested the effectiveness of the nanocomposite in solar cells and air purification photocatalysts.

The embedded nanocomposite material of TiO 2 the component of color-sensitized and perovskite-based solar cells examined as an alternative to conventional silicon-based photovoltaic cells. The nano composite material increased the energy conversion rates of the solar cells 40 percent to 66 percent.

TiO 2 nanoparticles are the most common photocatalyst material in commercially available air purifying or disinfecting devices. TiO 2 can only be activated with ultraviolet light, which makes it much less efficient indoors. It is also ineffective in the conversion of nitric oxide (NO) to nitrogen dioxide (NO 2 ) at a rate of less than 10 percent.

When PolyU’s nanostructure was embedded in a photocatalyst, it provided a graph superhighway for electrons to transport faster to generate superanions to oxidize absorbed contaminants, bacteria and viruses. The graft core also significantly increased the surface exposed to light absorption and capture of harmful molecules. It also harvested more light energy over all wavelengths. Semiconductor nanofibres converted about 70 percent of NO to NO seven times more than usual TiO nanoparticles.

They also tested how well their nanostructure breaks down formaldehyde, a nasty volatile organic compound commonly found in new or renovated buildings and new cars. PolyU’s embedded graphite catalyst could again break down three times more formaldehyde than TiO 2 nanoparticles without added nanostructure.

The new nanocomposite has a wide range of other potential applications, such as hydrogen production with water splitting, biochemical sensors with increased velocity and sensitivity, and lower impedance lithium batteries and increased storage.

Explore further:
Team develops new semiconductor nanofiber with excellent chargeability

Provided by:
Hong Kong Polytechnic University

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