Researchers develop a path to liquid solar cells that can be printed onto surfaces

April 25, 2012, University of Southern California

Scientists at USC have developed a potential pathway to cheap, stable solar cells made from nanocrystals so small they can exist as a liquid ink and be painted or printed onto clear surfaces.

The solar nanocrystals are about four in size — meaning you could fit more than 250,000,000,000 on the head of a pin — and float them in a solution, so "like you print a newspaper, you can print solar cells," said Richard L. Brutchey, assistant professor of chemistry at the USC Dornsife College of Letters, Arts and Sciences.

Brutchey and USC postdoctoral researcher David H. Webber developed a new coating for the nanocrystals, which are made of the semiconductor cadmium selenide. Their research is featured as a "hot article" this month in the international journal for inorganic chemistry Dalton Transactions.

Liquid nanocrystal solar cells are cheaper to fabricate than available single-crystal silicon wafer solar cells but are not nearly as efficient at converting sunlight to electricity. Brutchey and Webber solved one of the key problems of liquid solar cells: how to create a stable liquid that also conducts electricity.

In the past, organic ligand molecules were attached to the nanocrystals to keep them stable and to prevent them from sticking together. These molecules also insulated the crystals, making the whole thing terrible at conducting electricity.

"That has been a real challenge in this field," Brutchey said.

Brutchey and Webber discovered a synthetic ligand that not only works well at stabilizing nanocrystals, but actually builds tiny bridges connecting the nanocrystals to help transmit current.

With a relatively low-temperature process, the researchers' method also allows for the possibility that can be printed onto plastic instead of glass without any issues with melting – resulting in a flexible solar panel that can be shaped to fit anywhere.

As they continue their research, Brutchey said he plans to work on nanocrystals built from materials other than cadmium, which is restricted in commercial applications due to toxicity.

"While the commercialization of this technology is still years away, we see a clear path forward toward integrating this into the next generation of solar cell technologies," Brutchey said.

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not rated yet Apr 25, 2012
This should make folding solar cell wings for spacecraft far more predictable long term. Short term, it might be a little rough, however, with proper handling and learning, this short term knowledge gaining should result in long term benefits.
not rated yet Apr 25, 2012
Solar cell paint could be put on sails for boats, get some energy when the wind doesn't blow, maybe do a couple of knots at least to get somewhat going with no wind or diesel fuel.

Also would be nice on electric cars, painted with solar cell paint, maybe get a kw or so to help recharge the batteries on a hot summer day, extend the range when driving in the sun.
5 / 5 (1) Apr 25, 2012
This should make folding solar cell wings for spacecraft far more predictable long term.

For spacecraft other issues are much more important than 'cheap production'. In space efficiency reigns supreme.
Compared to the cost of getting 1kg into orbit the cost of getting the best and most efficient solar cells is negligible.

Also would be nice on electric cars, painted with solar cell paint, maybe get a kw

The amount of extended range would be absolutely minimal (conservatively estimating you'd get 61 miles instead of 60 miles.)
Probably the only reason for puttin this on the roof would be for running the AC when you're sitting in a traffic jam, so that you won't be in danger of running out of batteries.
not rated yet Apr 27, 2012

The amount of extended range would be absolutely minimal (conservatively estimating you'd get 61 miles instead of 60 miles.)

[citation needed]

too many variables.
here's a few to consider.
*electrical storage efficiency
*electrical motor efficiency
*solar cell efficiency
*mechanical power train efficiency

How much energy does 1 mile of movement in an electric car take? Does it not take additional energy from a standstill? Is this amount of energy the same for all electric cars? These need answers before you can estimate anything.

As far as I can tell your line of thinking is around the same line of thinking that Toyota engineers had when they decided to partially run the AC blower off of the roof mounted solar panel during times of electrical need or when the car is sitting idle, the difference being that the engineers did so with numbers and study.

You're presuming a new liquid solar suspension that gets rid of intrinsic resistance will have the same numbers.
not rated yet Apr 30, 2012
Sure would be nice if we could re-task some of the printing presses from struggling newspapers for this purpose. Sadly, it's not likely to be as easy as that, but wouldn't it boost sales if the Sunday shopping supplements included a sheet of solar cells.

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