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Instead of installing solar panels on your roof—how about just giving your house a new paint job? Of course you’d have to be sure to use solar paint. That’s what a group of Notre Dame researchers has created, detailing the recipe in the journal ACS Nano. [Matthew P. Genovese, Ian V. Lightcap, and Prashant V. Kamat, "Sun-Believable Solar Paint. a Transformative One-Step Approach for Designing Nanocrystalline Solar Cells"]
The paint contains nanoparticles of titanium dioxide—which gives whiteness to sunscreen and powdered sugar. The particles are coated with semiconducting cadmium nanocrystals, and mixed with water and alcohol, to create a golden yellow paste. The researchers dubbed the product “Sunbelievable.” They brushed it onto a conductive glass electrode, and attached that to a counter-electrode, to create a complete circuit.
When they shined light on the tiny solar cell, it pumped out a small current. The efficiency of the light-to-electricity conversion was only about one percent—much lower than the 10 to 15 percent efficiency of conventional silicon cells.
But the researchers say this paint is relatively cheap, can be made in any color, and doesn’t require a clean room to manufacture, like silicon cells—just a bench top. If they can up the efficiency a bit, a future Tom Sawyer could make an electric fence.
—Christopher Intagliata
[The above text is a transcript of this podcast.]
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23 Comments
Add CommentPaint cars with this stuff and throw away the electric plug/engine. Coat road surfaces with this stuff and turn the roads into an enormous wifi network. Paint houses with this stuff and no more electric bills! Of course, none of this will happen because the only reason it was invented was so scientists could publish for bragging rights and so the journalist who wrote this story could have something to report. The energy policies of this nation is as closely guarded by the rich as their little puffy hemorroids.
Reply | Report Abuse | Link to thisIn a sunny environment, it would take more than a month to generate enough electricity from painting an electric automobile to recharge its batteries. However, painting the road is a rather brilliant idea.
Reply | Report Abuse | Link to thisDo you know what 1% conversion efficiency means? It means that you would have to sit in direct tropical sunlight for about an hour in order to accumulate enough energy to move a "Smart Car" about 100 feet. Change that to 100% conversion efficiency (which even the best solar cells are nowhere near) and your completely solar conversion coated car might move along at 2 miles per hour.
Reply | Report Abuse | Link to thisA gallon of gasoline is the refined product of thousands and thousands of hours of solar energy imparted to a rather large fern or other plant millions of years ago. You're not going to replace it with a solar cell.
Since Santa didn't bring me a $35 copy of the report it's unclear how the 'paint' is configured with the glass electrodes for large scale applications such as picket fences... Does this mean we'd have to live in glass houses?
Reply | Report Abuse | Link to thisWell, a gallon of water could move a car nearly a thousand miles, on nothing but the 12v system and an ICE that was devoid of a catalytic converter and that dumb computer. No emissions but water, no need for either. That current catalytic converter sucks up almost 70% of the fuel we burn, just to reduce emissions. Now, that was a beautiful plan put forth by the Petroleum Institute.
Reply | Report Abuse | Link to thisThere must be some interesting math you are doing. If you make statements like "current catalytic converter sucks up almost 70% of the fuel we burn", which is a statement that probably lacks any real research, you should reference something relevant to prove it. Because a gasoline car is only 27% efficient (theoretically), doesn't mean the rest of the energy is lost in the 'cat'. A diesel car is about 40% efficient (theoretically). Rolling resistance with fat tires and wind resistance constitute a large portion of the loss of efficiency, as do all the mechanicals, hundreds of moving parts in an internal combustion engine, drive train, etc. I don't think you understand how a catalytic convertor works ... you can remove it and replace it with a straight pipe (illegally) and you will not see a noticeable difference in mileage.
Reply | Report Abuse | Link to thisAs for Didonai's painting roads, or even some median or shoulder area (to avoid the constant wear of traffic) ... brilliant! Many, if not most interstate highways have metal cabling or guardrails between lanes, might easily used (as a second purpose) as a low quality, but universally available wifi antenna.
Reply | Report Abuse | Link to this... yes, but don't throw any stones ...
Reply | Report Abuse | Link to thisYou would think that Scientific American would actually have a correct headline about energy conversion. Light is electricity. Photons are the fundamental carrier of the electromagnetic force from the sun or in a tiny solar cell and wiring. I know it's a common expression but we are really capturing photon energy from light waves and sending that energy down a wire using the slow movement of electrons in matter (current) as charge carriers for the electrical energy of photons.
Reply | Report Abuse | Link to thisIt seems silly for some to scoff at this type of research as if it were fair to compare efficiency of fossil fuels (which have had billions spent on R&D over many decades) against brand new technologies like this solar paint...
Reply | Report Abuse | Link to thisHeck, put 20% of the R&D into solar that ever went into fossil fuel engines and chemistry and give it half the research time and likely it will perform as well or better in the end.
Yes, gasoline is quiet efficient, we get it. The engines are highly engineered and can be even further tweaked for even better efficiency.... we get it, but darn, there is that pesky global warming problem. So get over it already!
Other techs, given time and focus, can do as well or better, and avoid the fossil fuel pitfalls. Yes, for every one new solution that works in the end, there will be a bunch that didn't work, and were a "waste" of money... that is how R&D works. Sitting back making snide comments about the one's that don't work, or that just serve as stepping stones to the solutions that will work in the end, is just petty and small minded. If you want to help, then apply your mind to helping the scientists involved identify the dead ends earlier and help them focus on the higher potential new solutions, but try to be part of the solution.
One day, solar will be cheap, and efficient, and, along with other new technologies will be a majority stakeholder in our power supply... and people will look back in wonder that anyone would have clung to fossil fuels as the best answer and mocked the development of solar.
How durable is this paint? What is the pattern of it's degradation? There has been a decades-long effort to get rid of lead paint from our environment, and now there could be a product that spreads cadmium everywhere; that element is a kissing cousin of lead and is a known heavy metal contaminant. Please, just a little more research before we start spreading this glop all over our houses, fences, roads and roofs!
Reply | Report Abuse | Link to thisThe hype is a prerequisite for obtaining research funding. The research is interesting but the hype ignores the cost of the substrate. It is the cost benefit ratio of the whole system that is important.
Reply | Report Abuse | Link to thisIt would not make any difference if the entire GDP was spent on solar research, it would not change the fundamental physics. The earth is still going to rotate giving approx 50% no sunshine. Clouds will interrupt sunshine as will shadow from adjoining natural or man made structures, no matter how you collect it or store it the system can never approach 100% efficiency from collection to utilisation. The only solar collection system that really works in suitable climates is for solar hot water. Hot water is easy & cheap to store, even for a couple of days. Even this simple use of solar does not approach 100% efficiency due to thermal losses, reflection off the collector & other factors. Of course no other system approaches 100% either. Cost benefit is all important. Solar hot water does this without subsidies.
Reply | Report Abuse | Link to thisAnother point that is glossed over is that solar energy does not come squeaky clean either. Particularly when it comes to PVs. Some very nasty chemicals are involved.
Or one or more of the efforts to develop solar-driven synthesis of gasoline from CO2 will bear sufficient fruit to make gasoline largely known as merely the common, energy-dense, easy-to-use storage medium of solar energy, and people will wonder at how old timey folks used to drill for the stuff underground instead of just making it.
Reply | Report Abuse | Link to thisPut the collectors in space and make them from materials mined from asteroids. No earthside chemical pollution. (There would be little bit of an energy influx, however.)
Reply | Report Abuse | Link to thisAnother pipe dream. Money spent on teaching mathematics & physics would save billions. Then people like you would understand the limits. A US gallon of petrol contains 36.67 KWh of energy. One twenty gallon tank full 733.4 KWh. An hour of sunlight at mid day with clear skies has approx 1KWh of energy. The highest conversion rate of solar to vegetation with ideal nutrients & Co2 infusion is 7%. Harvesting & processing into bio fuel consumes at least 50% of the contained energy & not all the vegetative matter can be converted to fuel. Even supposing that it could, you are down to 3.5% of your solar input. This means you would need a collection area of 2707 square metres operating under ideal conditions for an hour for one tank of gas. Imagine a pond big enough to fuel 1000 cars. Allow five hours per day of 1KWhm2 input. 28168412.97836994 square metres of collection area required, that is equivalent to an area 28 kilometres long by 1 kilometre wide. For a million cars 167 kilometres long x 167 kilometres wide. There are about 250 million registered vehicles in the US. An area 500 kilometres long by 500 kilometres wide would be required to collect enough energy to fuel the US fleet once in ten days with 20 gallons of gas. Add the roads, supporting infrastructure, vast quantity of water, nutrients & thousands of support staff. Well there is also the little matter of where you put it. In the desert? Remember the above figures are for ideal growing conditions. That is in the tropics. Anything less, add more area. Then there are cloudy days, rain & so drainage. Also dilution of the ideal nutrient mix from rainfall or concentration through evaporation, contamination of the growing tanks by competing bacteria & diseases plus many other problems.
Reply | Report Abuse | Link to thisNow you have that sorted you can start on the electricity requirements.
Paint the roads with this stuff so cars can retain a full battery charge so long as it keeps to public roads via ambient charge by proximity to the road surface..or to special storage cells at predictable locations along the path of highways. States could require a road use tax from each automobile to fund maintenance of the special automobile electrical grid. This would render cars as vital as the roads.
Reply | Report Abuse | Link to thisThe paint is only half of the device. The other half is the glass substrate. Would make an interesting road. You are not alone though. Those who believe in alternative energy generally ignore any down side.
Reply | Report Abuse | Link to thisThis is very good news. Perhaps i can stest this paint on my house where we have the sun every day.
Reply | Report Abuse | Link to thisThis is beter then putting the panels on the roof.
regards,
Delvin, Curacao
If you're looking for more details on the solar paint, check out the slideshare posted by the authors:
Reply | Report Abuse | Link to thishttp://www.slideshare.net/kamatlab/slideshare-solar-paint-10881513
this still is practical, imagine if we made a enormous glass platform painted with this solar paint in the desert. If it was big enough, it could power countries, and seeing as how the Sahara is in little use currently... plus, it wouldn't effect the albedo of the area if the paint color was the same as the sand, and glass is still SiO2 just like sand...
Reply | Report Abuse | Link to this"A gallon of gasoline is the refined product of thousands and thousands of hours of solar energy imparted to a rather large fern or other plant millions of years ago. You're not going to replace it with a solar cell."
Reply | Report Abuse | Link to thisJoeMerchant, the implication of your statement is that it's not possible to get enough energy from solar cells to power a car. However, solar cars already exist, even with the current levels of conversion efficiencies. Search for it if you don't believe me. They're not mainstream yet, but improve the conversion efficiencies (and costs) enough and they could be.
Who says the conductive substrate has to be glass?
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