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Is Nano always the way? -- Why nano?


Saniya has covered this talk already, and I just want to throw a few cents of mine here, as someone who call himself a nanochemist. I recall Professor George Whitesides once compared nano to a teenager: At a certain point, nano seems to be able to do everything, and solve every problem, just like a teenager who believe that s/he can do everything. And as this teenager gets older and older, a growing realization kicked in and reality-check occurs. Same is happening with nano.

Questions such as this one beg the assumption that there are justifications beyond pure intellectual curiosity. Professor Dresselhaus answered this question by first looking at what the major challenges we are facing now, and her list includes energy, physics of life, and information technology. And by relating the solutions to each of these challenges with nano, she tried to identify whether or not nano made a different. A particular successful example is that thermoelectric materials, in which nano is the enabling factor that boosts the figure of merit of thermalelectric materials -- ZT (which I don't actually know what it is short for, and any enlightenment on this issue is welcomed) by a factor of two. However, in other areas where nano didn't make a significant difference, going nano isn't the way. Her answer to the question is "yes, nano is very important, but not always."

I guess the answer itself isn't as important as the process it is solved here. And I think the message here is that staying relevant is just as important as being novel.


Saniya LeBlanc

ZT = (electrical conductivity*Seebeck coefficient*Temperature)/(thermal conductivity)

What does this mean? For a high ZT, we need a material that lets electrons shoot through it (high electrical conductivity). When there is a temperature gradient across the material, a large voltage needs to develop across it (Seebeck coefficient). However, heat should not transfer well through the material (low thermal conductivity). One problem is that part of the thermal conductivity (electron component) increases if the electrical conductivity increases, so people are focusing on decreasing the other part of the thermal conductivity (the lattice component from phonons). All of the properties change with temperature, so the T indicates the temperature at which the material is being used. Hope that helps.

Wendong Wang

Thanks for the explanation. Looks clearer now.

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