Chemical engineers from MIT University managed to find a method to concentrate solar radiation energy using carbon nanotubes at a rate XNUMX times higher than conventional photovoltaic cells. Such nanotubes will be able to create antennas that will capture and concentrate the light energy, and will enable the development of smaller and more efficient solar arrays.
"Instead of having your entire roof contain photovoltaic cells (solar panels), you can spread out small dots that are themselves photovoltaic cells, with antennas leading to the content of photons from the sun's radiation," said Michael Strano, a professor of chemical engineering who led the research. The research findings were published in the scientific journal Nature Materials.
The researchers' innovative antennas could also be used for other applications where focusing of light is required, such as telescopes or night vision devices.
Solar panels generate electricity by converting photons (units of light energy) into electrical current. The innovative nanotube antenna significantly increases the number of photons that can be absorbed and the amount of light that is converted into energy that can be routed to a solar cell.
The antenna consists of a fiber rope ten micrometers long and four micrometers thick, containing about thirty million carbon nanotubes. The research team created, for the first time ever, a fiber consisting of two layers of nanotubes with different electronic properties - in particular, different band gaps (energies).
In any material, the electrons can be in different energy levels. When a photon (light energy) hits the surface, it causes the excitation of an electron and its "jumping" to a higher energy level, which is unique to each and every material. The interaction between the electron that absorbed a surplus of energy and the "hole" it left behind in this "jump" is called an "exciton" (the entry in Wikipedia), and the energy difference between the hole and the electron is known as a bandgap.
The inner layer of the antenna contains nanotubes with a small bandgap, and the nanotubes found in the outer layer have a higher bandgap. This fact is important since excitons tend to flow from a state of high energy to a state of low energy. In this case, this means that the excitons in the outer layer flow into the inner layer, where they can exist in a lower energy state (but still an excited state).
As a result, when light energy hits the material, all excitons flow to the center of the fiber, where they are focused and concentrated. The researchers have not yet built a photovoltaic device using the innovative antenna, but they plan to do so. In such a device, the antenna will concentrate the photons before the photovoltaic cell converts them into an electric current. This will be possible due to the construction of the antenna around a core of semi-conducting material.
The interface between the semiconductor and the nanotubes will result in the separation of the electron from its hole, with electrons being collected at one electrode connected to the inner semiconductor and holes being collected at the other electrode connected to the nanotubes. In such an arrangement, the device will be able to generate an electric current. According to the researchers, the efficiency of such a solar cell will depend on the type of materials used to build the electrodes.
This research team is the first to succeed in preparing nanotube fibers that can control the properties of different layers found in them, an achievement made possible thanks to contemporary advances in methods for separating nanotubes with different properties.
While the price of the nanotubes was the main limitation in the past, in recent years their cost has been decreasing as chemical companies utilize their production capacity. "At some point in the not-too-distant future, carbon nanotubes will cost as much as polymeric materials sold today," notes the lead researcher. "At such a cost, their addition to a solar cell will become economically negligible compared to the production cost itself and the raw materials of the cell itself, just as today coating with polymers and polymer components make up a very small part of the cost of the photovoltaic cell."
The research team is now working on finding ways to minimize the energy losses in the flow of excitons through the fiber, and on ways to create more than one exciton per photon.
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Michael is right. Only with potential differences of heat, electricity, light, mass and more is it possible to produce energy.
You can also read here from the website of the United States Department of Energy
http://www.energysavers.gov/your_home/space_heating_cooling/index.cfm/mytopic=12620
Read about heat pumps and you will see that what I said is written in their description:
http://he.wikipedia.org/wiki/%D7%9E%D7%A9%D7%90%D7%91%D7%AA_%D7%97%D7%95%D7%9D
Michael,
Indeed yes, I am talking about extracting heat energy from the atmosphere and turning it into available mechanical or electrical energy.
Partially the subject is applied in heat pumps as I have already explained, and what I propose is actually utilizing the subject and turning the energy into mechanical or electrical energy.
The topic of heat pumps works, is known and has evidence in the field.
Joseph:
I understood that you are proposing to extract heat energy from an atmosphere that initially has no temperature differences.
This is what Carnot's theorem says is infeasible.
But I don't intend to argue - after all, you didn't detail the things at a level that allows you to refer to the details.
Michael,
If so, then you didn't understand the idea, as a result of the process, temperature differences are created that allow the absorption of energy from the immediate environment.
All laws of thermodynamics are preserved.
The closest system to this is a heat pump where you produce more heating energy than electrical energy spent in the process.
And here is the uniqueness in the matter of rolling forward and instead of producing heat I produce mechanical or electrical energy
Joseph:
It does violate.
See, for example, here:
http://en.wikipedia.org/wiki/Carnot%27s_theorem_(thermodynamics)
Your idea claims to work even when there are no temperature differences
Michael Shalom,
This is not a violation of the laws of thermodynamics and calculations based on the laws of thermodynamics show feasibility
for your information.
Joseph:
There is nothing wrong with your idea other than breaking the laws of thermodynamics.
I saw that you have been advertising the idea for a long time and I am not surprised that you are still looking for an investor.
There is no need to develop facilities or accumulators for energy storage. The Earth's atmosphere itself is a large reservoir of energy that needs and can be utilized. A system for producing energy from the heat stored in the Earth's atmosphere. The project could revolutionize the global energy market. This is a venture to produce real green energy from the heat stored in the Earth's atmosphere, the Earth's atmosphere is actually the largest energy accumulator that exists. There is no need to develop it but only to utilize it to our advantage, it is available throughout the hours of the day and does not directly depend on the weather because even at extremely low temperatures and in extremely cold areas the air is still relatively charged with heat energy like any other body or substance. It is an electro-mechanical system that knows how to convert the heat stored in the Earth's atmosphere into electrical or mechanical energy and does not depend on different types of fuel. The system can be small and personal, for a house, a building, a factory, and as a power station this system also has additional bonuses. - The system does not cause its immediate environment to warm, but the opposite. In that it absorbs heat energy from the environment, it causes it to cool down or slow down the rate of natural temperature rise. - As a byproduct of the system, it can be used as a cold source for air conditioning or cooling systems that will be integrated with it in houses or buildings and save a lot of air conditioning energy in addition to the production of electrical or mechanical energy. The system does not take up a large area like other systems and can be integrated and minimized within buildings or as part of a built or existing structure. There is no need for the energy invested in the development of other energy sources and their transportation, such as mineral energy or biofuel, which also requires fields for cultivation and this is at the expense of forests and food cultivation. The system produces energy throughout the hours of the day regardless of light, darkness, wind or weather and can be located almost anywhere on the planet. Further development of the system can integrate it into various land, sea and even aerial means of transport.
On the face of it and as it seems this type of system has all the advantages we are looking for from green energy. More details can be seen on the website: http://www.webix.name/greenenergy
A little about the philosophical and scientific basis of the project:
Today, most energy production systems are based on the correct basic assumption that in order to produce energy we need a potential difference of pressure/altitude and heat, when there is an agreement that to achieve this we need a heat source whose temperature is higher than the environment or the creation of such a source by burning fuels or nuclear fission. In all the real and known green ways we utilize the pressure differences on the earth's surface to create energy in wind turbines or utilize waterfalls as long as we have water flow, and solar heating energy. In some of the facilities and in another part of the facilities we utilize other physical phenomena. The green ways to produce energy are not new or groundbreaking and their scientific basis has been known for a long time, but either they are limited in their ability to produce energy or they are not available throughout the day or the seasons of the year. What's more, their production process is relatively expensive and they don't stand up to the Japanese standards themselves, and as a matter of fact, they need a government subsidy to make them economically viable for the investor.
After clarifying the existing options and without underestimating the innovations and developments, these options are still limited and too expensive solutions. We should continue to develop them and try to get the most out of them, but we should not concentrate only on them. Relatively cheap. There is a certain system that actually comes from the world of air conditioning and produces energy three times more than the energy invested in it and it is called a heat pump, a heat pump or an air conditioner in a heating cycle produces more heat energy than is normally invested as electrical energy to operate them, but this is where it stops and the existing technology does not produce energy from this fact electrical or mechanical. Here is the place to ask the question whether it is possible to produce energy only between high and low potential or whether it is also possible to produce energy from low to high potential or more precisely whether it is possible to create a potential difference not only as a result of heating but also as a result of cooling. The answer is yes we can. Dealing with the question resulted in an unusual and unusual idea in which in electromechanical ways we extract heat from the environment, turning it into mechanical or electrical energy and this without investing energy from an external source, the system is able to generate enough energy for its operation and provide additional excess energy for general consumption.
In how much time can the researchers bring the research to industrial implementation. Or when I can mount the antenna on my roof
It is written in a way that does not make it easy for the reader to understand. But sounds interesting. It is the large structure and its character that governs quantum behaviors. This is a beautiful insight that deserves to be applied.