Quantum world without queues could lead to better solar cells

December 19, 2014, Lund University

In a recent study from Lund University in Sweden, researchers have used new technology to study extremely fast processes in solar cells. The research results form a concrete step towards more efficient solar cells.

The upper limit for the efficiency of normal is around 33 per cent. However, researchers now see a possibility to raise that limit to over 40 per cent, thereby significantly improving the potential of this energy source.

The experiments in the present study involved 'juggling' on with photons, i.e. , and electrons. Quantum level refers to the microcosm of the world formed by individual atoms and their building blocks. In juggling the particles, the researchers took advantage of the fact that the laws of nature work slightly differently on quantum level than what we are used to in our world.

"We were actually a bit surprised that it worked", said Tönu Pullerits, Professor of Chemical Physics at Lund University.

In the study, Tönu Pullerits and his colleagues studied solar cells containing nanometre-sized balls of material known as quantum dots. These quantum dots can be likened to individual artificial atoms of semiconductor materials. When sunlight hits the , two electrons can be extracted from one photon, which can increase the efficiency of the solar cells.

"This would mean a radical improvement to solar cells", said Professor Pullerits.

The explanation for this effect lies in the laws of quantum mechanics that control particles on the quantum scale. The phenomenon is called and can lead to a type of energy transfer that produces an almost perfect flow of energy without any obstacles.

Coherence opens up a possibility that the flow of energy can find the shortest route by taking all the possible routes at the same time and then selecting the best. To stretch a metaphor, you could compare it to avoiding choosing a queue in the supermarket – instead you can stand in all the queues and see which moves the fastest. Although in reality, the process is extremely fast: it takes a matter of billionths of a second in the quantum world. There are ongoing discussions between researchers on whether the phenomenon might be used by certain photosynthetic organisms to capture sunlight.

Over recent years, Tönu Pullerits and his colleagues have conducted research to try to understand and control the coherence phenomenon in order to make use of it in more efficient solar cells, but the results can also be used in other contexts where the transport and interaction of electrons and photons is decisive, such as in future high-speed quantum electronics.

The present study is a collaboration between researchers at Lund University and in Oregon, USA. The study has been published in the scientific journal Nature Communications.

Explore further: Researchers glimpse pathway of sunlight to electricity

More information: "Coherent two-dimensional photocurrent spectroscopy in a PbS quantum dot photocell," Khadga J. Karki, Julia R. Widom, Joachim Seibt, Ian Moody, Mark C. Lonergan, Tõnu Pullerits & Andrew H. Marcus, Nature Communications, DOI: 10.1038/ncomms6869

Related Stories

New nanomaterial increases yield of solar cells

August 26, 2013

Researchers from the FOM Foundation, Delft University of Technology, Toyota Motor Europe and the University of California have developed a nanostructure with which they can make solar cells highly efficient. The researchers ...

Nontoxic quantum dot research improves solar cells

December 11, 2013

Solar cells made with low-cost, nontoxic copper-based quantum dots can achieve unprecedented longevity and efficiency, according to a study by Los Alamos National Laboratory and Sharp Corporation.

Recommended for you

New insights into magnetic quantum effects in solids

January 23, 2019

Using a new computational method, an international collaboration has succeeded for the first time in systematically investigating magnetic quantum effects in the well-known 3-D pyrochlore Heisenberg model. The surprising ...

Rapid and continuous 3-D printing with light

January 22, 2019

Three-dimensional (3-D) printing, also known as additive manufacturing (AM), can transform a material layer by layer to build an object of interest. 3-D printing is not a new concept, since stereolithography printers have ...

Scientists discover new quantum spin liquid

January 22, 2019

An international research team led by the University of Liverpool and McMaster University has made a significant breakthrough in the search for new states of matter.

Researchers capture an image of negative capacitance in action

January 21, 2019

For the first time ever, an international team of researchers imaged the microscopic state of negative capacitance. This novel result provides researchers with fundamental, atomistic insight into the physics of negative capacitance, ...

Toward ultrafast spintronics

January 21, 2019

Electronics have advanced through continuous improvements in microprocessor technology since the 1960s. However, this process of refinement is projected to stall in the near future due to constraints imposed by the laws of ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

EyeNStein
not rated yet Dec 19, 2014
An interesting and unexpected result. I'd have expected the photon to have preferentially chosen a less efficient path to deposit its energy.
If the higher energy photons yield extra electrons and improve the efficiency: This is indeed good news.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.