Subscribe to our free daily newsletters
  Solar Energy News  




Subscribe to our free daily newsletters



SOLAR DAILY
New approaches for hybrid solar cells
by Staff Writers
Munich, Germany (SPX) Dec 10, 2015


Filled with suitable organic polymers the highly porous germanium nanofilm becomes a hybrid solar cell. Because the germanium nanostructure forms an inverse opal-structure, the material shimmers like opal. Image courtesy Andreas Battenberg and TUM. For a larger version of this image please go here.

Using a new procedure researchers at the Technical University of Munich (TUM) and the Ludwig Maximillians University of Munich (LMU) can now produce extremely thin and robust, yet highly porous semiconductor layers. A very promising material - for small, light-weight, flexible solar cells, for example, or electrodes improving the performance of rechargeable batteries.

The coating on the wafer that Professor Thomas Fassler, chair of Inorganic Chemistry with a Focus on Novel Materials at TU Munich, holds in his hands shimmers like an opal. And it has amazing properties: It is hard as a crystal, exceptionally thin and - since it is highly porous - light as a feather.

By integrating suitable organic polymers into the pores of the material, the scientists can custom tailor the electrical properties of the ensuing hybrid material. The design not only saves space, it also creates large interface surfaces that improve overall effectiveness.

"You can imagine our raw material as a porous scaffold with a structure akin to a honeycomb. The walls comprise inorganic, semiconducting germanium, which can produce and store electric charges. Since the honeycomb walls are extremely thin, charges can flow along short paths," explains Fassler.

The new design: bottom-up instead of top-down
But, to transform brittle, hard germanium into a flexible and porous layer the researchers had to apply a few tricks. Traditionally, etching processes are used to structure the surface of germanium. However, this top-down approach is difficult to control on an atomic level. The new procedure solves this problem.

Together with his team, Fassler established a synthesis methodology to fabricate the desired structures very precisely and reproducibly. The raw material is germanium with atoms arranged in clusters of nine. Since these clusters are electrically charged, they repel each other as long as they are dissolved. Netting only takes place when the solvent is evaporated.

This can be easily achieved by applying heat of 500 C or it can be chemically induced, by adding germanium chloride, for example. By using other chlorides like phosphorous chloride the germanium structures can be easily doped. This allows the researchers to directly adjust the properties of the resulting nanomaterials in a very targeted manner.

Tiny synthetic beads as nanotemplates
To give the germanium clusters the desired porous structure, the LMU researcher Dr. Dina Fattakhova-Rohlfing has developed a methodology to enable nanostructuring: Tiny polymer beads form three-dimensional templates in an initial step.

In the next step, the germanium-cluster solution fills the gaps between the beads. As soon as stable germanium networks have formed on the surface of the tiny beads, the templates are removed by applying heat. What remains is the highly porous nanofilm.

The deployed polymer beads have a diameter of 50 to 200 nanometers and form an opal structure. The germanium scaffold that emerges on the surface acts as a negative mold - an inverse opal structure is formed. Thus, the nanolayers shimmer like an opal.

"The porous germanium alone has unique optical and electrical properties that many energy relevant applications can profit from," says LMU researcher Dr. Dina Fattakhova-Rohlfing, who, in collaboration with Fassler, developed the material. "Beyond that, we can fill the pores with a wide variety of functional materials, thereby creating a broad range of novel hybrid materials."

Nanolayers pave the road to portable photovoltaic solutions
"When combined with polymers, porous germanium structures are suitable for the development of a new generation of stable, extremely light-weight and flexible solar cells that can charge mobile phones, cameras and laptops while on the road," explains the physicist Peter Muller-Buschbaum, professor of functional materials at TU Munich.

Manufacturers around the world are on the lookout for light-weight and robust materials to use in portable solar cells. To date they have used primarily organic compounds, which are sensitive and have relatively short lifetimes. Heat and light decompose the polymers and cause the performance to degrade. Here, the thin but robust germanium hybrid layers provide a real alternative.

Nanolayers for new battery systems
Next, the researchers want to use the new technology to manufacture highly porous silicon layers. The layers are currently being tested as anodes for rechargeable batteries. They could conceivably replace the graphite layers currently used in batteries to improve their capacity.

The research was funded by the "Solar Technologies Go Hybrid" program of the Bavarian State Ministry of Science, in the context of the excellence cluster "Nanosystems Initiative Munich (NIM), the German Research Foundation (DFG) and the Center for Nanosciences (CeNS). Zintl Clusters as Wet Chemical Precursors for Germanium Nanomorphologies with Tunable Composition; Manuel M. Bentlohner, Markus Waibel, Patrick Zeller, Kuhu Sarkar, Peter Muller-Buschbaum, Dina Fattakhova-Rohlfing, Thomas F. Fassler Angewandte Chemie, online 03.12.2015 - DOI: 10.1002/anie.201508246


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

.


Related Links
Technical University of Munich
All About Solar Energy at SolarDaily.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
SOLAR DAILY
Exploring the limits for high-performance LEDs and solar cells
London, UK (SPX) Dec 09, 2015
Hybrid optoelectronic devices based on blends of hard and soft semiconductors can combine the properties of the two material types, opening the possibility for devices with novel functionality and properties, such as cheap and scalable solution-based processing methods. However, the efficiency of such devices is limited by the relatively slow electronic communication between the material compone ... read more


SOLAR DAILY
OX2 wins concession for one of Sweden's largest biogas plants

A more efficient way of converting ethanol to a better alternative fuel

Now is the time to uncover the secrets of the Earth's microbiomes

Brazil pins renewable energy hopes on 2nd generation ethanol

SOLAR DAILY
Swimming devices could deliver drugs inside the body

Robot adds new twist to NIST antenna measurements and calibrations

Kennedy now firmly established as a 21st Century Spaceport

These are the robots you're looking for

SOLAR DAILY
UN report takes global view of 'green energy choices'

Dogger Bank lidar confirms technology meets met masts for wind data collection

Pilot Hill Wind Project Closes Financing from GE and MetLife

German power giant RWE to spin off renewables business

SOLAR DAILY
Global bicycle ownership has halved in 30 years

GM to sell China-made vehicle in US first

Eliminating 'springback' to help make environmentally friendly cars

Lyft allies with Asia peers in Uber challenge

SOLAR DAILY
Carbon capture analyst: 'Coal should stay in the ground'

Saft to supply LION batteries to power Textron control stations

36 countries launch world alliance for geothermal energy

Australia riding coal train despite climate pleas

SOLAR DAILY
New Delhi to construct six fast breeder reactors over 15 years

Russian ready to reprocess spent Fukushima nuclear fuel

South Korea offers to participate in Czech nuclear program

PPPL physicists propose new plasma-based method to treat radioactive waste

SOLAR DAILY
Addressing climate change should start with energy efficiency

CO2 emissions set for historic fall in 2015: study

Mexico to spend $23 billion to cut greenhouse gases

New Zealand joins geothermal alliance

SOLAR DAILY
N. Korea 'declares war' on deforestation at Paris climate talks

US forest products in the global economy

At UN talks, African countries aim to restore 100 mn hectares of forest

Eyes in the sky track health of Earth's African 'lung'




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement