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 Researchers pave the way for ionotronic nanodevices
23.02.2017 | Aalto University

nachricht Microhotplates for a smart gas sensor
22.02.2017 | Toyohashi University of Technology

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

From rocks in Colorado, evidence of a 'chaotic solar system'

23.02.2017 | Physics and Astronomy

'Quartz' crystals at the Earth's core power its magnetic field

23.02.2017 | Earth Sciences

Antimicrobial substances identified in Komodo dragon blood

23.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>