Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Liquid crystals line up to make self-healing photovoltaic device

03.11.2008
Molecules containing both electron donors and acceptors have been functionalized with tails that control their arrangement in a liquid-crystal photovoltaic device

A huge market is developing for small disposable electronic devices, ranging from security tags to point-of-care diagnostics. Many of these devices require a power source, and photovoltaic devices (solar cells) are an attractive option.

However, the expense of preparing and processing inorganic semiconductors used in traditional solar cells precludes their use in such applications. Organic photovoltaic devices, meanwhile have great potential in this area; they are relatively easy to prepare and can be processed by simple techniques such as inkjet printing.

Organic photovoltaic devices contain both electron donors, which release an electron when irradiated, and electron acceptors, which complete the circuit necessary to convert light energy into electrical energy. However, mixtures of typical electron donors such as ð-conjugated oligomers—short chains of repeated, unsaturated, organic molecules, with alternating double and single bonds—and electron acceptors, such as C60 (buckminsterfullerene), have a tendency to form alternating stacks that results in lower efficiency. A partial solution is to directly attach the electron donor to the electron acceptor by a covalent bond and have both in a single molecule, but it is still important to have control over how the molecules pack together.

Now, a team of Japanese researchers including Takuzo Aida from the University of Tokyo and Masaki Takata from the RIKEN SPring-8 Center in Harima have designed liquid crystals—a phase that flows like a liquid but has short-range order between the molecules—that spontaneously assemble to form a donor-acceptor array (1). “It’s important to form separated columns or layers of the donors and acceptors, and to make a large contact area between them,” explains Yohei Yamamoto, another member of the team from the Japan Science and Technology Agency in Tokyo.

The molecules they designed feature a fullerene—the electron acceptor—at one end and a thiophene oligomer—the electron donor—at the other. A hydrophobic, or water-repellent, tail is attached to the donor end and a hydrophilic, or water-loving, tail is attached to the acceptor end. This functionalization ensures that the molecules of the liquid crystal line up to produce ordered layers of donors and acceptors and results in efficient photovoltaic behavior. “The liquid characteristics are useful as well,” notes Yamamoto, “the devices are self-healing as defects in the layer structure can be repaired by a simple heating and cooling process.” The design principles developed in this work should lead to the development of high-efficiency organic photovoltaic devices.

(1) Li, W.-S., Yamamoto, Y., Fukushima, T., Saeki, A., Seki, S., Tagawa, S., Masunaga, H., Sasaki, S., Takata, M. & Aida, T. Amphiphilic molecular design as a rational strategy for tailoring bicontinuous electron donor and acceptor arrays: photoconductive liquid crystalline oligothiophene–C60 dyads. Journal of the American Chemical Society 130, 8886–8887 (2008).

The corresponding author for this highlight is based at the RIKEN Structural Materials Science Laboratory

Saeko Okada | ResearchSEA
Further information:
http://www.rikenresearch.riken.jp/research/576/
http://www.researchsea.com

More articles from Power and Electrical Engineering:

nachricht Stretchable biofuel cells extract energy from sweat to power wearable devices
22.08.2017 | University of California - San Diego

nachricht Laser sensor LAH-G1 - optical distance sensors with measurement value display
15.08.2017 | WayCon Positionsmesstechnik GmbH

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

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

26.07.2017 | Event News

 
Latest News

Cholesterol-lowering drugs may fight infectious disease

22.08.2017 | Health and Medicine

Meter-sized single-crystal graphene growth becomes possible

22.08.2017 | Materials Sciences

Repairing damaged hearts with self-healing heart cells

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>