Print 22 comment(s) - last by 90014.. on Jan 20 at 11:43 PM

Conjugated polymers, like this one here, are special organic molecules which exhibit special quantum effects which help them transfer electrons like a semiconductor. This makes them a perfect candidate for cheap organic solar cells and circuits, as well as a possible building block for quantum computers.  (Source: University of Bath)
New U of T research looks to create organic solar cells by using special quantum effect

Imagine having cheap, printable solar cells at your fingertips, woven into your clothing, streaming power into your mobile electronics.  Organic electronics, a field which includes organic solar cells and organic transistor circuits, has many advantages, the biggest of which is the ability to be printed easily, and the ability to flex without breaking.

Greg Scholes and Elisabetta Collini of University of Toronto's Department of Chemistry have discovered the mechanism behind how light triggers the transport of electricity in one promising organic solar material.  Their new discovery could be applied to producing cheaper and more efficient cells.

The team looked at conjugated polymers, one of the most efficient organic materials available for solar power production.  These long molecules can be also used in transistors and LEDs.  They behave roughly like semiconductors, while retaining important organic characteristics.  When exposed to light, they produce energy, which is transferred down their chain, eventually reaching other molecules and finally leaving the cell.

However, the way this transfer occurs was poorly understood, until now, making it difficult to optimize.  Explains Professor Collini, "One of the biggest obstacles to organic solar cells is that it is difficult to control what happens after light is absorbed: whether the desired property is transmitting energy, storing information or emitting light.  Our experiment suggests it is possible to achieve control using quantum effects, even under relatively normal conditions."

Her colleague, Professor Scholes describes this quantum effect responsible for the transmission, noted, "We found that the ultrafast movement of energy through and between molecules happens by a quantum-mechanical mechanism rather than through random hopping, even at room temperature.  This is extraordinary and will greatly influence future work in the field because everyone thought that these kinds of quantum effects could only operate in complex systems at very low temperatures."

As well as being a breakthrough for organic electronics, the discovery could also yield advances in quantum computing.  One of the key obstacles currently in quantum computing is the ultra-low temperatures needed to maintain useful quantum effects.  The discovery of such effects occurring at room temperature could lead to important breakthroughs in building quantum computers.

On a technical level, the team used bursts from an ultrashort laser to trigger atoms of the polymer into a quantum-mechanical state.  In this state the atoms were simultaneously in the ground state and at the energy level of the absorb photon.  This phenomenon is a type of superposition known as quantum coherence.  They used more lasers and a sophisticated measuring technique to then determine if the quantum state was being transferred between atoms on the chain. 

Describes Professor Scholes, "It turns out that it only moves along polymer chains.  The chemical framework that makes up the chain is a crucial ingredient for enabling quantum coherent energy transfer. In the absence of the chemical framework, energy is funneled by chance, rather than design.  This means that a chemical property – structure -- can be used to steer the ultrafast migration of energy using quantum coherence. The unique properties of conjugated polymers continue to surprise us."

The findings are reported in the Jan. 16 edition of the journal Science. The work was sponsored by the Natural Sciences and Engineering Research Council of Canada.

Comments     Threshold

This article is over a month old, voting and posting comments is disabled

Organic solar cells
By bobsmith1492 on 1/16/2009 3:33:43 PM , Rating: 2
Organic solar cells are nothing new, by the way.

For example:

There are many others of different shapes and sizes. They can even be used to generate electricity directly:

RE: Organic solar cells
By omnicronx on 1/16/2009 3:51:26 PM , Rating: 3
Organic solar cells are nothing new, by the way.
The article pretty much points this out, the point here is that they now know they can control the movement of energy in ways they previous could not.
This means that a chemical property – structure -- can be used to steer the ultrafast migration of energy using quantum coherence.
Knowing why, and how this happens is a totally different matter ;)

RE: Organic solar cells
By bobsmith1492 on 1/16/2009 5:03:43 PM , Rating: 2
Very possible, but that's not the point of my post... ;)

"The whole principle [of censorship] is wrong. It's like demanding that grown men live on skim milk because the baby can't have steak." -- Robert Heinlein

Copyright 2016 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki