New inexpensive solar cell design

Aug 03, 2010

One of the most promising technologies for making inexpensive but reasonably efficient solar photovoltaic cells just got much cheaper. Scientists at the University of Toronto in Canada have shown that inexpensive nickel can work just as well as gold for one of the critical electrical contacts that gather the electrical current produced by their colloidal quantum dot solar cells.

The change to nickel can reduce the cell's already low material costs by 40 to 80 percent, says Lukasz Brzozowski, the director of the Photovoltaics Research Program in Professor Ted Sargent's group. They present their research in the July 12, 2010 issue of Applied Physics Letters.

are nanoscale bits of a that are created using low-cost, high-throughput chemical reactions in liquid solutions. Since their properties vary according to their size, quantum dots can be made to match the illumination spectrum. Half of all sunlight, for example, is in the , most of which cannot be collected by silicon-based . Sargent's group has pioneered the design and development of quantum dot solar cells that gather both visible and infrared light. They have reached a power-conversion efficiency as high as 5 percent and aim to improve that to 10 percent before commercialization.

At first, nickel did not appear to do the job. "It was intermixing with our quantum dots, forming a compound that blocked the current flow from the device," says Dr. Ratan Debnath, first author on the group's paper. Adding just one nanometer of lithium fluoride between the nickel and the dots created a barrier that stopped the contamination, and the cell's efficiency jumped back up to the expected level.

This is the latest of several recent solar-cell milestones by the Canadian researchers. "We have been able to increase dramatically the efficiency of our photovoltaics over the last several years and continue to hold the performance world records," Professor Sargent said.

Explore further: Tiny magnetic DNA particles protect olive oil from counterfeiters

More information: The article, "Depleted-Heterojunction Colloidal Quantum Dot Photovoltaics Employing Low-Cost Electrical Contacts" by Ratan Debnath, Mark Theodore Greiner, Illan Kramer, Armin Fischer, Jiang Tang, Aaron Barkhouse, Xihua Wang, Larissa Levina, Z. H. Lu and Edward H. Sargent will appear in the journal Applied Physics Letters. See: apl.aip.org/applab/v97/i2/p023109_s1

Provided by American Institute of Physics

4.8 /5 (15 votes)

Related Stories

Quantum Dots Could Boost Solar Cell Efficiency

Mar 11, 2009

(PhysOrg.com) -- The transition to environmentally benign energy sources is one of the most significant challenges of the 21st century. Solar power, which uses sunlight to generate electricity, is one promising source. It ...

Hot Electrons Could Double Solar Cell Power Efficiency

Dec 18, 2009

Scientists have experimentally verified a theory suggesting that hot electrons could double the output of solar cells. The researchers, from Boston College, have built solar cells that successfully use hot ...

Recommended for you

Nanomaterial outsmarts ions

Apr 22, 2014

Ions are an essential tool in chip manufacturing, but these electrically charged atoms can also be used to produce nano-sieves with homogeneously distributed pores. A particularly large number of electrons, ...

User comments : 0

More news stories

Research proves nanobubbles are superstable

The intense research interest in surface nanobubbles arises from their potential applications in microfluidics and the scientific challenge for controlling their fundamental physical properties. One of the ...

Genetic code of the deadly tsetse fly unraveled

Mining the genome of the disease-transmitting tsetse fly, researchers have revealed the genetic adaptions that allow it to have such unique biology and transmit disease to both humans and animals.