Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nano-Sandwich Technique Slims Down Solar Cells, Improves Efficiency

26.06.2012
Researchers from North Carolina State University have found a way to create much slimmer thin-film solar cells without sacrificing the cells’ ability to absorb solar energy. Making the cells thinner should significantly decrease manufacturing costs for the technology.

“We were able to create solar cells using a ‘nanoscale sandwich’ design with an ultra-thin ‘active’ layer,” says Dr. Linyou Cao, an assistant professor of materials science and engineering at NC State and co-author of a paper describing the research. “For example, we created a solar cell with an active layer of amorphous silicon that is only 70 nanometers (nm) thick.

This is a significant improvement, because typical thin-film solar cells currently on the market that also use amorphous silicon have active layers between 300 and 500 nm thick.” The “active” layer in thin-film solar cells is the layer of material that actually absorbs solar energy for conversion into electricity or chemical fuel.

“The technique we’ve developed is very important because it can be generally applied to many other solar cell materials, such as cadmium telluride, copper indium gallium selenide, and organic materials,” Cao adds.

The new technique relies largely on conventional manufacturing processes, but results in a very different finished product. The first step is to create a pattern on the substrate using standard lithography techniques. The pattern outlines structures made of transparent, dielectric material measuring between 200 and 300 nm. The researchers then coat the substrate and the nanostructures with an extremely thin layer of active material, such as amorphous silicon. This active layer is then coated with another layer of dielectric material.

Using dielectric nanostructures beneath the active layer creates a thin film with elevated surfaces evenly spaced all along the film – like crenellations at the top of a medieval castle.

“One key aspect of this technique is the design of the ‘nanoscale sandwich,’ with the active materials in the middle of two dielectric layers. The nanostructures act as very efficient optical antennas,” Cao says, “focusing the solar energy into the active material. This focusing means we can use a thinner active layer without sacrificing performance. In the conventional thin-film design, using a thinner active layer would impair the solar cell’s efficiency.”

The paper, “Dielectric Core-shell Optical Antennas for Strong Solar Absorption Enhancement,” is published online in Nano Letters. Lead author of the paper is Yiling Yu, a Ph.D. student at NC State. Co-authors include Drs. Vivian Ferry and Paul Alivisatos of the University of California, Berkeley. The research was supported, in part, by the U.S. Department of Energy.

-shipman-

Note to Editors: The study abstract follows.

“Dielectric Core-shell Optical Antennas for Strong Solar Absorption Enhancement”

Authors: Yiling Yu and Linyou Cao, North Carolina State University; Vivian E. Ferry and A. Paul Alivisatos, U.C. Berkeley

Published: Online, Nano Letters

Abstract: We demonstrate a new light trapping technique of dielectric core-shell optical antennas to strongly enhance solar absorption. This approach can allow the thickness of active materials in solar cells lowered by almost one order of magnitude without scarifying solar absorption capability. For example, it can enable a 70 nm thick a-Si:H thin film to absorb 90% of incident solar radiation above the bandgap, which would otherwise require a thickness of 400 nm in typical ARC-coated thin films. This strong enhancement arises from a controlled optical antenna effect in patterned core-shell nanostructures that consist of absorbing semiconductors and non- absorbing dielectric materials. This core-shell optical antenna benefits from a multiplication of enhancements contributed from leaky mode resonances (LMRs) in the semiconductor part and anti-reflection effects in the dielectric part. We investigate the fundamental mechanism for this enhancement multiplication, and demonstrate that the size ratio of the semiconductor and the dielectric parts in the core-shell structure is key for optimizing the enhancement. By enabling strong solar absorption enhancement, this approach holds promise for cost reduction and efficiency improvement of solar conversion devices, including solar cells and solar to fuel systems. It can generally apply to a wide range of inorganic and organic active materials. This dielectric core-shell antenna can also find applications in other photonic devices such as photodetectors, sensors and solid-state lighting.

Matt Shipman | EurekAlert!
Further information:
http://www.ncsu.edu

More articles from Power and Electrical Engineering:

nachricht Improved stability of plastic light-emitting diodes
19.04.2018 | Max-Planck-Institut für Polymerforschung

nachricht Intelligent components for the power grid of the future
18.04.2018 | Christian-Albrechts-Universität zu Kiel

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: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

Im Focus: The Future of Ultrafast Solid-State Physics

In an article that appears in the journal “Review of Modern Physics”, researchers at the Laboratory for Attosecond Physics (LAP) assess the current state of the field of ultrafast physics and consider its implications for future technologies.

Physicists can now control light in both time and space with hitherto unimagined precision. This is particularly true for the ability to generate ultrashort...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Diamond-like carbon is formed differently to what was believed -- machine learning enables development of new model

19.04.2018 | Materials Sciences

Electromagnetic wizardry: Wireless power transfer enhanced by backward signal

19.04.2018 | Physics and Astronomy

Ultrafast electron oscillation and dephasing monitored by attosecond light source

19.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>