Carbon Nanotube Towers Could Increase Solar Power

Vict0r writes "Researchers at the Georgia Tech Research Institute have recently demonstrated a way to grow carbon nanotubes in towers. The article also discusses applications for solar cells." From the article: "Reflections off the Gothamesque towers would provide more opportunity for each photon of sunlight to interact with the p/n junction of the cell. That would increase the power output from PV cells of a given size, or allow cells to be made smaller while producing the same amount of power."

Comments

Carbon Nanotubes....in towers?

[eddiegee]

So where's my Space Elevator?

Re:Carbon Nanotubes....in towers?

[Rei]

No. The problem with tubes this small is that there is insufficient van der waals force holding them together; the tubes are strong, but the force keeping them as a single bundle isn't. And probably won't be unless we can produce quite large tubes. One alternative is that, under high pressures, nanotubes interlink and trade their strong sp2 bonds (graphite) for weaker, but still quite strong sp3 bonds (diamond) between tubes. In theory, these interlinked ropes (not really nanotubes, but a new material) should be quite producable once regular vdw-bonded nanotube ropes without any sort of binder in them become producable and affordable.

There's another problem with space elevators, though: not only would interlinked tubes prove somewhat weaker than non-interlinked tubes in all likelyhood, but non-interlinked SWNTs proved rather weak in direct tensile strength tests. One test that I read about had a maximum strength of just over 60GPa, instead of the >100 typically called for to produce a reasonable space elevator on Earth. Now there are many different types of SWNTs depending on how the graphite is rolled up, so they could vary, but signs don't look good.

Slightly OT

[frankthechicken]

For soldiers operating in the field, especially in desert areas that receive lots of sunlight, the new "solar tube" cells could provide an alternate power source for the growing number of electronic devices they use

Given the amount of energy this "growing number of electronic devices" probably puts out, doesn't it make the slodiers easier to spot due to the energy signatures they are putting out? If so, doesn't it slightly impact on the actual usefulness of the electronic devices?

I'm guessing this is factored in, but how much shielding is possible, and how far would the new "solar tube" be able to be shield it's energy signature from the enemy?

Re:Slightly OT

[Rei]

I'd actually been thinking about that. For example, picture the speaker on a communications device. Speakers give off a lot of EMF (they're effectively a big fluctuating electromagnet pulling on a diaphragm) - even shielded ones are generally pretty easy to detect and tell what sound was coming from the speaker. CRT monitors (not that common on portables) pump out lots of EMF, too (run "Tempest for Eliza" some time - you don't even need a sensitive directional antenna to listen in). I've read about keyboards have been tempested from over 50 feet away.

What good is an encrypted signal when the people that you're hunting in a city have a good parabolic antenna pointed at you through a wall that they're hiding behind and are listening to the signal from your radio? Heck, they don't even need to know what you're saying, just that you're there.

Of course, pretty much everything about warfare would be a heck of a lot harder if the US actually fought a *real* enemy instead of collapsing third-world nations armed with reject Soviet equipment from the 1950s and 1960s.

But not word...

[davecrusoe]

"For soldiers operating in the field, especially in desert areas that receive lots of sunlight, the new "solar tube" cells could provide an alternate power source for the growing number of electronic devices they use. Without the need for trucking in fuel, compact PV cells could directly power certain applications or be used to recharge batteries in soldiers' equipment..." But, no word about innovative residential or consumer uses for the material? What about powering mobile computing systems for rural schools in India, or for use in purifying water in Africa? Sigh.

20 um vertical structures?!?

[Sebastopol]

preface: my nanotech is limited to semiconductor process only.

looking at the image, the towers appear to be 20um cubes, and the tubes look incredibly uniform. That is some impressive feat to build such a tall structure!

this makes me think of 3D model creation tools that use a laser and a tank of epoxy-like goop to 'draw' a 3D prototype of a design.

can this accomplishment be extended to this technique to "render" nanodevices (er, microdevice machines), out of tubes?

Make solar cells like leaves not like guts !

[mishmash]

No. If surface area mattered then leaves (nature's way of capturing solar energy) would have folds and protrusions like the gut does to increase surface area. What leaves do is make sure that some of the light gets through to the next layer. This happens both in an individual leaf - light is not caught just at the top surface but all the way through the leaf. Also a leaves don't trap all the available light, some is left for leaves below - it's totally dark walking through a forest. Make the solar cells more transparant - thats the way to get the effect of increased surface area the article referes to.

double insulated towers

[Anonymous Coward]

A simple and donated to the non-patentable public domain by me solution is:

a. get double paned glass windows
b. install on 100 story office tower
c. channel the air from inside of one window to the one above it (chaining them until top of building)
d. put wind turbines at top of building

Yeah.

[Grendel Drago]

And I'm sure we'll have solar as a major component of distributed power generation right after that commercial fusion plant gets built.

--grendel drago

20um towers? OLD NEWS!

[Anonymous Coward]

This is really silly. The only thing new about this is the application idea. People have been growing multiwall nanotube towers since 1998... All the new nanotube field emission displays are based on them. Single-walled towers (which this MAY be refering to, but the article is too sparse to be sure) have been around for at least 2 years, vertical SWNT published first by Maruyama in japan, followed by a much better paper (all sorts of shapes of nanotube towers, up to 2.5mm tall... yes, MILIMETERS) by Iijima -- father of nanotubes in Science, last summer).

- nanotube researcher