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McEuen cautions that his work on carbon nanotube photovoltaics is fundamental. "We've made the world's smallest solar cell, and that's not necessarily a good thing," he says. To take advantage of the nanotubes' superefficiency, researchers will first have to develop methods for making large arrays of the diodes. "We're not at a point where we can scale up carbon nanotubes, but that should be the ultimate goal," says Lee, who developed the first nanotube diodes while a researcher at General Electric.
It's not clear why the nanotube photovoltaic cell offers this two-for-one energy conversion. "It's mysterious to us," says McEuen. However, the most likely reason is that while conventional solar materials have only one energy level for electrons to move through, carbon nanotubes have several. And two of them just happen to be very well matched: one of the energy levels, or bandgaps, is twice as high as the other. "We may have gotten lucky, and it has very little to do with the fact that it's a carbon nanotube," says McEuen. This means, McEuen hopes, that even if it proves too challenging to make arrays of nanotube solar cells, materials scientists can look for pairs of materials that have these kinds of matched bandgaps, and layer them to make solar cells that do with two materials what the single nanotube cells can do. "Maybe the answer won't be in nanotubes, but in another pair of materials," McEuen says.
Nanomaterials could help solar cells convert more sunlight into electricity than once thought possible.
Nanosolar's new factory could help lower the price of solar power, if the market cooperates.
Let me try to give a lay man answer. Heat is the lowest grade of energy and electricity is a higher grade. To convert energy from one form to another there is alway lost in form of heat. Photovoltaic technologies convert light (photons) into electricity. Some of the ligh energy (photon) is lost into heat during the process. Heat can be converted into mechanical energy through several techniques such as producing presurized vapor in a boiler. That's what thermosolar technology does. The challege is to do the conversion with the least loss possible.
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This document is part of the “How-To Guide for Most Common Measurements” centralized resource portal. This tutorial provides a detailed guide for measurement and device considerations to take temperature measurements using thermocouples. Get an introduction to thermocouples, which are inexpensive sensing devices widely used with PC-based data acquisition systems. Also review some specific thermocouple examples and learn how thermocouples work and ways to integrate them into a data acquisition measurement system.
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1 Comment
Energy Loss in Solar Cells
I am a layman, but love to cogitate on this stuff, so pardon me if I am right out or very simplistic and uninformed.
It seems to me that if raw solar is so inefficient and that heat is always the by-product, could there not be a way to produce a heat-electric effect along side of the solar producer that might make use of the ever-present heat? Or, Heat-to-chemo-to-electric effect. The thought comes to mind that it might not be space-efficient, but seems like instead of trying to eliminate the heat, is there no way to use it? At least until the cells become a lot more useable? Maybe they could both evolve in tandem?
I am sure you learned folks out there have been down this road, but I keep seeing "heat" in so many of these articles, it seems like if it is always present, there has to be a way to use it effectively.
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