Questions for Janice Boercker

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In Fall 2006 Janice Boercker answered visitors' questions about nanotechnology.

Your Comments, Thoughts, Questions, Ideas

greg's picture
greg says:

How long will it be before solar cell technology will be cheap and efficient? In the future will it be possible for individual homes to be self sufficient, not need to be connected to a power grid?

posted on Fri, 09/15/2006 - 3:22pm
Janice Boercker's picture
Janice Boercker says:

Greg,
It is hard to give an exact time frame for when technology and the political environment will be such that solar energy can be implemented on very large scale. There are big companies (Sharp, Kyocera, BP Solar, Shell Solar, etc.) that are ramping up production and have even started making profit. This is the first necessary step; businesses must be able to make money. The dye sensitized solar cell technology that we work on is relatively new. There are only two companies, one in Australia and one in Lowell Massachusetts that are making dye-sensitized solar cells. So, the answer is definitely in the near future.
In regards to your second question, yes, in the future, it may be possible to have each home be self sufficient without being connected to a grid but the answer depends on where you live and availability of new technology to locally store solar energy. Currently, there is no reliable, inexpensive and safe local storage technology. However, it is also possible to be connected to the power grid and still be self sufficient. When a home produces more than what is needed, power can be sent to other locations via the grid. Conversely, one can buy power from the grid when solar energy production is not adequate.

posted on Sat, 09/16/2006 - 5:43pm
Ryan F.   No wait, R. France's picture
Ryan F. No wait, R. France says:

What's an electron? What's your favorite solar cell company? What is the absorbtion spectra you can expect from your type of cell and what efficiency do you hope to get with it? You go girl. Solar cells rock.

posted on Mon, 09/18/2006 - 2:53pm
Janice Boercker's picture
Janice Boercker says:

Ryan,
The electron is a subatomic particle that carries a negative charge. Electrons orbit the nucleus of the atom in what are called orbitals. The nucleus is also made up of two other subatomic particles, the proton, which has a positive charge, and the neutron, which has a zero charge. Electrons can also flow through materials, such as the semiconductor nanowires in the DSSC. When electrons flow it is called current and from this current one can extract electrical energy.

I don't have a favorite solar cell company although I am partial to those that are exploring the dye sensitized solar cell technology (DSSC).

The absorption spectra from our DSSCs is the same as the absorption spectra of the organic dye we use. It has a maximum around 550 nanometer and then slowly drops to zero by about 900 nanometer. It looks deep purple. In these cells, it is best to use dyes that absorb the visible wavelengths present in the solar spectrum. The best dyes tend to be deep purple or black (because they absorb all or nearly all wavelengths that our eyes can see.)

The maximum reported efficiency of a ZnO nanowire DSSC is ~2.5%. To improve this efficiency, we are trying to increase the surface area of the nanowires so more dye can be adsorbed on their surfaces.

posted on Sun, 09/24/2006 - 7:01pm
Liza's picture
Liza says:

What breakthroughs do you think will be necessary before we start using solar cells widely on residential buildings? Or is that even the right way to go? Would it be better, environmentally, to stay with conventional power for homes, but use solar cells for businesses and other big institutions?

posted on Fri, 09/22/2006 - 5:09pm
Janice Boercker's picture
Janice Boercker says:

Liza,
Figuring out how to make efficient solar cells which are also inexpensive is the main technological issue that needs to be solved before solar cells can be used on a large scale. Commercial silicon solar cells are sufficiently efficient (~15%) for wide spread implementation. However solar energy from these cells is ten times more expensive than the energy we are currently using from fossil fuels. Solar energy cannot be implemented on a large scale until energy companies can sell the energy at a price competitive with the energy from fossil fuels.

Whether or not solar cells are a good idea for the environment, be it on homes or businesses, all depends on the amount of pollution created when the solar cells are manufactured. This is a hard thing to quantify because so often it is not until it's too late that the environmental consequences from pollutants are found, the effect of CFC's on the ozone layer for example. However, solar cells would definitely reduce CO2 emissions which is the main culprit responsible for global warming. Unlike conventional energy sources, solar cells will be a one time CO2 polluter during production and then will be carbon emission free for the rest of their lifetime. This should average out to significantly less CO2 emission overall when compared to conventional sources. Assuming no other harmful pollutants are released from solar cell manufacturing, implementation of solar energy will be a good idea.

posted on Thu, 09/28/2006 - 11:10am
Anonymous's picture
Anonymous says:

I always wonder about tradeoffs. For example, I use a wood stove to heat my home for most of the winter, but I have no way of knowing whether that's good for the environment, because I'm not contributing to pollution from burning coal or natural gas, or bad because I'm burning wood, which also has environmental effects. With solar cells, how toxic is the manufacturing process? If people suddenly started using solar cells, would we be creating another mess somewhere else?

posted on Fri, 09/22/2006 - 5:14pm
Janice Boercker's picture
Janice Boercker says:

That is a good question, and one that will hopefully be carefully examined before the implementation of solar cells. In terms of our work, most of the components of the dye-sensitized solar cells are non-toxic. TiO2 and ZnO, for example, are used in sunscreens. However, the toxicity of the dye is currently undetermined and will be further examined before wide spread implementation.

posted on Thu, 09/28/2006 - 11:13am
Joe's picture
Joe says:

How would solar power be converted into a stored form of energy during times when solar output is low, when it is cloudy, or non existent, like at night?

posted on Mon, 10/02/2006 - 10:48am
Janice Boercker's picture
Janice Boercker says:

Joe,
During times of high solar incidence (bright sunny days) there will be more energy created by the solar cell then needed by the business or residence using the cell. This extra energy may be stored in a battery. During cloudy days or at night the battery may be used to supply electricity. There are several different types of batteries. These batteries resemble the kind used in golf carts. Which type of battery to use would depend on the location of the business or residence using the solar cell. Typically you would need a bank of batteries to provide for the voltage and capacity needed in typical applications. An alternative is to be connected to the electrical grid so that electricity can be sold and bought from the grid depending on local production and use. For example, you may use some energy but sell most of it during a sunny day and buy it back when it is cloudy or night time.

posted on Thu, 10/05/2006 - 5:16pm
Katie Estep's picture
Katie Estep says:

One of the shortcomings of nanowires is the cost. You talk about growing longer, thinner, and denser clusters of nanowires to improve the efficiency. What are solutions that you are working on in order to do this? Is it a different type of material or a different process to create them?

posted on Tue, 10/03/2006 - 2:27pm
Janice Boercker's picture
Janice Boercker says:

Katie,
High cost is the main shortcoming of conventional silicon solar cells not nanowire-based solar cells. Silicon solar cells are the most common solar cells used today. You have probably seen them on buildings and on the side of the road in remote areas where they power phones, whether stations etc. The reason you do not see silicon solar cells utilized more is that they are expensive to manufacture due to the need for highly defect-free silicon. The ZnO nanowires we are working on may be a cheaper alternative to the current silicon solar cells, once the efficiency is improved. To increase the density of wires we are trying to align them better so that they do not run into each other and stop growing. We are also trying to understand how they grow so we can alter the chemistry to slow the lateral growth while increasing axial growth. This is one way to get longer thinner wires.

posted on Thu, 10/05/2006 - 5:18pm
Michael's picture
Michael says:

What nanotechnology is currently used in the production of solar energy? How is nanotechnology important research?

posted on Sun, 10/08/2006 - 3:06pm
Janice Boercker's picture
Janice Boercker says:

Michael,
Nanotechnology is important because materials with nanometer dimensions tend to have novel properties that they do not have when they are in the bulk (large quantities of material). Nanotechnology is important becuase it allows us to harness these useful properties for new helpful technologies. One example of such a property is surface area. As a material is broken down into smaller and smaller particles more and more surface area is created. We utilize this increased surface area in our dye-sensitized solar cells. The surface area of the nanowires is up to ~200 time that of a flat surface. This increased surface area allows us to absorb more dye than we would be able to on a flat surface and thus create a solar cell. In order to improve the efficiency of the dye-sensitized solar cells we are using nanotechnology to try to make longer and thinner nanowires with even higher surface area for more dye absorption.

posted on Sat, 10/21/2006 - 9:26am
Anonymous's picture
Anonymous says:

What is the difference between nano and micro?

posted on Tue, 10/10/2006 - 1:18pm
Janice Boercker's picture
Janice Boercker says:

“Nano” and “micro” are prefixes that mean “one billionth” (10^-9) and “one millionth” (10^-6) respectively. When “nano” is put in front of a quantity it means one billionth of the quantity and when micron is put in front of a quantity it means one millionth of the quantity. For example, one nanometer is one billionth of a meter, the thickness of a human hair is ~20,000 nanometers. One microliter is one millionth of a liter, the weight of a mircoliter of water is 0.001 grams. The difference between nano and micro is a factor of 1000. For example there are 1000 nanometer is a micrometer.

posted on Sat, 10/21/2006 - 9:28am
Anonymous's picture
Anonymous says:

How did you become interested in nanotechnology?

posted on Wed, 10/11/2006 - 9:36am
Janice Boercker's picture
Janice Boercker says:

To be honest it was mostly by accident. Going to graduate school I new I liked electron microscopy (microscopes that use electrons to make the image and can have resolutions of ~0.2 nanometers) and was also interested in environmental issues, but I wasn’t totally sure what I wanted to do. Then I met Prof. Aydil, who was working on nanoparticle solar cells which was a perfect combination of my two interests. So I joined his research group and have been very happy since.

posted on Sat, 10/21/2006 - 9:29am
Anonymous's picture
Anonymous says:

Is there a regulatory agency for nanotechnology that is dealing with the potential risks posed by nanoparticles?

posted on Wed, 10/11/2006 - 9:40am
Janice Boercker's picture
Janice Boercker says:

Yes, there are several, in particular there is the National Institute for Occupational Safety and Health (NIOSH). They are looking into toxicity and risk of nanotechnology as well as possible controls and safety procedures.

posted on Sat, 10/21/2006 - 9:29am
chad's picture
chad says:

How will Nanotechnology help engineers over the next few years?

posted on Sat, 10/14/2006 - 11:55am
Janice Boercker's picture
Janice Boercker says:

Chad,
Nanotechnology will help engineers tap the useful properties of nanoscale materials and use them to enhance the quality of life. One example of this is “quantum dots” which are nanometer sized semiconductor particles which show novel electronic properties. These “quantum dots” can be used in many applications such solar cells, targeted drug delivery, biological labels and light emitted devices.

posted on Sat, 10/21/2006 - 9:31am
A First Lego League Team's picture
A First Lego League Team says:

Hello we are a FLL Team reserching nanotecnology. We are going to use your idea for the presentation that we have to give. We want to follow up on a recently posted question by Katie, one of our teammembers. How are you trying to align the nanowires? Also are you trying any other chemicals than the ZnO? Also we found an article in a recently puplished Popular Science magazine that they found a way to increese the efficiency of the scanning tuneling microscope. Would this help you understand the constuction of these nanowires better? How do you watch nanowires grow?

posted on Wed, 10/18/2006 - 6:19am
Janice Boercker's picture
Janice Boercker says:

Lego Team,
To align the ZnO nanowires we are working on understanding the effect of the seeding method we use to create the nanowires. We put a thin (1-2 nanoparticles high) ZnO nanoparticle layer down on our substrate first. Then we grow the wires from these particles. It is not fully understood how these wires grown from these seeds. For example, we don’t know if each seed grows into a nanowire or if several seeds grow into one nanowire. Learning more about this process will hopefully give us clues on how the wires grow. We can then use that information to alter the seeding and growth method to make the wires more aligned.
We are also looking into growth of TiO2 nanowires as well as the ZnO nanowires.
Yes, scanning tunneling microscopy can be very useful when trying to image the seed layer before the nanowire growth. So this new technology might help us. You should check out this paper: Greene et al. Nano Letters 2005, 5, 1231-1236. It has scanning tunneling microscopy images of ZnO seeds used to grow nanowires.
We use scanning electron microscopy (SEM) to watch the nanowires grow (one such image is shown on this site). To see how fast the wires are growing, we grow the nanowires for various lengths of time and then use scanning electron microscopy to find the height and width of the wires at the different time intervals.

posted on Sat, 10/21/2006 - 9:35am
Anonymous's picture
Anonymous says:

does the i pod nano really contain nano inside of it?

posted on Thu, 10/19/2006 - 1:23pm
Janice Boercker's picture
Janice Boercker says:

While, I’m no expert on the manufacturing of the ipod I would assume the answer is yes because nanotechnology is so prolific in the electronics industry. I do know, however, that they are they are thinking of coating the ipod screens with nanoparticles to the prevent scratching.

posted on Sat, 10/21/2006 - 9:35am
Anonymous's picture
Anonymous says:

where do you think nanotech will go in the near future?

posted on Fri, 10/20/2006 - 3:14pm
Janice Boercker's picture
Janice Boercker says:

Our ability to engineer on small length scales has been ever improving and with that technological devices are getting cheaper, smaller and faster. So in the near future I predict this trend to continue. However, there is really no limit to how small devices can be made (ignoring the uselessness of cell phones that are so tiny you can’t pick them up). Some people are even talking about molecular scale engineering being possible in the next 10-15 years. This would mean that one could build something molecule by molecule to the exact size and specification that want. So, if you wanted, for example, ZnO nanowires with an exact length and diameter you could build it ZnO by ZnO, and there you go. Now I doubt this will happen anytime soon, but it’s a possibility in the future.

posted on Sat, 11/04/2006 - 3:47pm
A FLL Team's picture
A FLL Team says:

Are nanotubes and nanowires the same?

posted on Fri, 10/20/2006 - 4:11pm
Janice Boercker's picture
Janice Boercker says:

FLL Team,
No, nanowires are solid all the way through, like a nanosized rod. Nanotubes on the other hand are like nanowires but with a hole in the center along the long axis like a nanosized pipe.

posted on Sat, 11/04/2006 - 3:48pm
jeffrey's picture
jeffrey says:

How many businesses or homes in Minnesota use solar energy?

posted on Sat, 10/21/2006 - 6:17pm
Janice Boercker's picture
Janice Boercker says:

Jeffrey,
While I’m not sure about the consumption in just Minnesota, solar energy use only accounts for 0.01% of the total global energy use. However, this number is increasing each year and the cheaper we can make solar cells the faster this number will rise.

posted on Sat, 11/04/2006 - 3:56pm
Anonymous's picture
Anonymous says:

What do you like most about your job?

posted on Mon, 10/23/2006 - 5:37pm
Janice Boercker's picture
Janice Boercker says:

I love being in the lab and experimenting with interesting chemicals and equipment. I never know what I’m going to find when I open a vessel or take a spectrum of a sample. It keeps me on my toes and keeps me thinking and challenging myself. I also really like discussing what I find with my advisor and lab partners trying to figure out what’s going on. Sometimes it’s frustrating when experiments are not going well, but it’s really fun when we finally have a breakthrough and understand something a little bit better.

posted on Sat, 11/04/2006 - 3:49pm
Elizabeth's picture
Elizabeth says:

Would it help to grow the nanowires upside down?

posted on Fri, 10/27/2006 - 2:40pm
Janice Boercker's picture
Janice Boercker says:

Elizabeth,
Yes, it does help to grow the nanowires upside down and that is exactly what we do. During the growth process nanowires grow on the surface of the substrate and this is called heterogeneous growth. However, larger wires, microns in diameter, also grow in the solution, which is called homogeneous growth. These larger wires fall on the nanowires when the substrate is facing up, so we place the substrate upside down in the reaction solution so the wires fall on the back of the susbtrate not on the nanowires.

posted on Sat, 11/04/2006 - 3:51pm
andrea's picture
andrea says:

I know that you have gotten this question millions of times, but I read all the FAQ's and I still haven't recieved an answer that satisfies my question. Is there a specific factor in nanotechnology that makes it worth investigating over something like improving the energy sources we already have? Or it the point to find as many things as possible and not discover their full potential?

posted on Sun, 11/19/2006 - 6:26pm