Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Solar cells: Pillars of light

30.05.2011
Nanopillars significantly boost the power conversion efficiency of thin-film solar cells

One of the major challenges in the world today is the energy crisis. The high demand and low supply of fossil fuel are driving up oil and food prices. Silicon-based solar cells are one of the most promising technologies for generating clean and renewable energy.

Using these devices to convert just a fraction of the sunlight that hits the earth each day into electricity could drastically cut society’s dependence on fossil fuels. Unfortunately, however, high-grade silicon crystals demand great care during the manufacturing process, making the resulting high production cost one of the main obstacles in the road to commercialization.

One way to bring down the production cost of these solar cells is to deposit layers of silicon onto cheaper substrates such as plastic or glass. However, this approach has one drawback: silicon thin films have lower power conversion efficiencies than bulk silicon crystals because they absorb less light and contain more defects. Patrick Lo at the A*STAR Institute of Microelectronics and co-workers[1] have now discovered an approach for increasing the power conversion efficiency of silicon thin films deposited on cheap substrates.

Low-grade silicon thin films suffer from one inherent problem: they cannot absorb photons whose wavelengths are larger than their film thickness. For instance, a standard, 800-nm-thick thin film may capture short-wavelength blue light, but will completely miss longer-wavelength red light. “To keep material costs low and improve light efficiency, the trick is to trap more photons, including those with medium wavelengths,” says Lo.

One way to trap more photons in the silicon thin film is to carve tiny silicon pillars—hundreds of nanometers in size—in the silicon surface (see image). Lo explains that the silicon nanopillars are like a forest of trees, in which light enters and cannot easily get out. “When light strikes the surface, it bounces a few more times along or inside the pillars before penetrating the bottom flat surface,” he says. “Each bouncing event increases the chances of photon absorption.”

Lo and co-workers used computer simulations to determine the best configuration for extracting electrical charges from the defect-ridden silicon films. They found that the upper portion of each pillar can be made extremely conductive by introducing large amounts of dopants. Lo and co-workers are now using these practical guidelines to engineer a prototype of this unique concept. “Working with nanostructures is a wonderful way to open paths that could overcome the limits set by conventional physics,” he notes.

The A*STAR-affiliated researchers contributing to this research are from the Institute of Microelectronics

Journal information

[1] Wong, S. M. et al. Design high-efficiency Si nanopillar-array-textured thin-film solar cell. IEEE Electron Device Letters 31, 335–337 (2010).

Lee Swee Heng | Research asia research news
Further information:
http://www.research.a-star.edu.sg/research/6332
http://www.researchsea.com

More articles from Power and Electrical Engineering:

nachricht Did you know that infrared heat and UV light contribute to the success of your barbecue?
26.07.2017 | Heraeus Noblelight GmbH

nachricht Ultrathin device harvests electricity from human motion
24.07.2017 | Vanderbilt University

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

 
Latest News

CCNY physicists master unexplored electron property

26.07.2017 | Physics and Astronomy

Molecular microscopy illuminates molecular motor motion

26.07.2017 | Life Sciences

Large-Mouthed Fish Was Top Predator After Mass Extinction

26.07.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>