We've told you how plastic can become fuel and form flexible batteries and transparent solar cells. Now, Wake Forest University scientists have created a new type of lighting made from thin layers of light-emitting polymer combined with nanomaterials that glow.
Based on alternating current (AC) field-induced polymer electroluminescent (FIPEL), the lighting device emits a soft, white light, unlike the harsh light from either fluorescents or LEDs. The light is similar to sunlight, and also flicker-free. The device itself is shatter-proof, avoiding broken glass and the hazardous mercury contained in compact fluorescent (CFL) bulbs.
Wake Forest University scientists have devised a shatterproof, white light, flicker-free lighting device based on field-induced polymer electroluminescent (FIPEL) technology. (Source: Wake Forest University)
The new lighting devices are also long-lasting, said David Carroll, professor of physics and director of the university's Center for Nanotechnology and Molecular Materials, in a press release. He owns one that has worked for about 10 years. The device has about the same efficiency as LEDs and is twice as efficient as CFLs. In addition to applications in office and home lighting, Carroll envisions the technology being used in large display lighting, such as signs on buses and subway cars, as well as store marquees.
The research team, which Carroll heads, made the lighting device from three layers of moldable, light-emitting polymer. Multi-walled carbon nanotubes (MWNTs) are dispersed in the active layer's polymer, sandwiched between two dielectric layers. The team described its work in an article in Organic Electronics.
According to the article:
An asymmetric device structure, using one dielectric layer, was used to study band alignment effects of carbon nanotubes in charge injection from a contact. The presence of MWNTs within the emissive layer facilitates effective internal charge generation in the symmetric devices, as would be expected if they acted as a charge source. The MWNTs effectively doped the polymer, modifying energy level alignment in the device and increasing field-induced polarization currents. Increase in light emission of five times is achieved in composite devices compared with the device without MWNTs.
The device is inexpensive to make, and the materials can be formed into many shapes and colors, from regular bulbs that fit household lamp and fixture sockets, to large 2-feet x 4-feet panels for office lighting. The team is working with a company to commercialize and manufacture the technology, and Carroll expects it to be available sometime this year.
Thanks, Ann for this awesome news and the free PDF. I'm amused / frustrated / encouraged that Professor Carroll has had an operating device for the past 10 years and we haven't seen faster commercialization of the FIPEL technology. A quick search shows the primary ingredient [Ir(pp)3] is fairly expensive in research quantities at $0.91 / milligram while the other components, PVK at $0.03 / mg and MWNT ($0.02 / mg) are relatively inexpensive. The device in this research shows a 500% increase in luminance. We can all hope that additional research will discover additional leaps in efficiency. Commercial availability later this year is fantastic.
This looks like a winner. Making a softer light than LEDs or CFLs would get a majority of the female market. My wife's biggest complaint about non-incandescent lights are the harshness of their light. As they say, happy wife happy life
Maybe we're all used to Silicon Valley-style announcements of new technology for sale right now in high volumes, and not of the long R&D cycle behind that technology. In materials technology, especially energy-related, development can take a long time. Thanks, William, for finding those cost figures. The main researcher has had a single working device for a long time--but not a bulb, and, presumably, a very expensive device, and, I'd guess, one he's been tinkering with as a prototype.
Ann, What a great article. Given the tremendous luminance output and efficiency of FIPEL and its applications for commerical and residential lighting, what happens to the lonely LED? I'm curious to know the thermal capabilities, in terms of watts, and how it stacks against high bright LEDs. I've worked on LED projects for automotive and residential lighting applications and the biggest challenged I had was thermal management of the LEDs and the switching mode power supplies. Also, to put a solid state lighting (SSL) product out on the market requires a tremendous amount of testing (6000hrs) to be Energy Star and DOE compliant per the SSL LM80 testing document. Once the SSL product meets the LM80 requirements, its ready to be a saleable consumer item for purchasing.
Thanks, mrdon, glad you liked the article. We give links in the blog to a detailed journal article that may have the info you're looking for. Regarding SSL, this technology doesn't sound like it qualifies.
I figured as much. I assumed I was seeing the 60hz flicker from the wall. I suppose it would be cheaper and last longer to not filter the signal. I imagine if the cap burst, the whole strand would be shot. Similar to the only series bulbs. One goes, the circuit is cut. I am sure a line conditioner is sold separate. In other words, a CAP in a box for $29.99.
Seems like this would be a good application for Christmas lights. When I was taking the tree down the other day it I thought about the market for wireless lights. Wifi Christmas lights that clip on. Program them any way you like or download you favorite after seeing it on utube. Write messages on the tree in lights for arriving guests.
My wife was house sitting in Princeton NJ, big house, big tree, and she heard a creak. Yes, the tree fell over as she was looking at it. All that heavy wire...
There seems to be some confusion here regarding the difference between prototypes and working products, and the amount of time it requires to move from the first to the second. I made an earlier comment on this subject: "Maybe we're all used to Silicon Valley-style announcements of new technology for sale right now in high volumes, and not of the long R&D cycle behind that technology. In materials technology, especially energy-related, development can take a long time...The main researcher has had a single working device for a long time--but not a bulb, and, presumably, a very expensive device, and, I'd guess, one he's been tinkering with as a prototype."
I'm betting the reason ARS Technica didn't get "performance numbers" is because they asked the wrong question. So far, AFAIK, this is a number of prototype devices, not a single actual bulb with wattage specs, which is what will be produced after commercialization efforts are completed. The details that are available can be found in the (free) journal article, which we provide a link to. They include varying luminance intensities.
Interesting technology that solves the problem of the fragility of lightbulbs, but like the other commenter I am surprised this hasn't been brought to light (no pun intended) sooner if the technology has been around so long. I'm not a massive fan of plastic, though, but it does sound like a more eco-friendly design with the elimination of mercury and the reduced production costs. Perhaps recycled plastic could even be used in mass production down the line?
I agree - the first question that popped into my head was why such a long time to market? I absolutely love the idea of unbreakable bulbs and hope this technology takes off. I think you have a great idea, Elizabeth - recycled plastics would go a long way in making them even more eco-friendly. Flicker-free is another plus - sounds like a winner if its cost-effective.
It would be great if recycled plastic could be used in devices such as this, but I think it's unlikely that will happen anytime soon. The plastic used in this device is a highly customized and engineered material, which is why it can do what it does. And plastics are not monolithic: they differ greatly in their ability to be recycled into something usable, and the vast majority of available recycled plastic in the US is still of only 1 or 2 types, as we discuss here
Perhaps in the future we'll have an existing, functional infrastructure with multiple known waste streams, so the specific recycled material a manufacturer needs is as easily obtainable as buying virgin plastic. But we're not there yet.
Thanks for the great information Ann - just goes to show how we take for granted things outside of our areas of expertise...that's what I love about this forum, it's a great way to learn from others. Makes perfect sense now that you've pointed it out...and a great idea about multiple waste streams fro recycled material. The logistical complexity would be huge but the payoff would be enormous.
Yes, I did wonder about that, Ann...if the material was so specialized that perhaps recycled plastic is not an option. Maybe down the line this could work but as you point out, we're definitely not there yet--which is a shame, because there is so much plastic in the world that goes to waste!
Ann, it seems that usage of plastic is increasing in various forms across different domains. Some of the good qualities of plastics like resistance to corrosion, low electric & thermal conductivity, durability etc can make them more adaptable and suitable for such missions.
It is interesting that rather than talk about candle power, the devices are described as less harsh than LED or florescent lights. A candle meets those criteria as well as a match, a glowing ember etc. Can anyone put this into terms of candle power per watt or some other real world measurement?
TommyH, I think you meant candela, not candle power. The latter is considered an obsolete unit of measurement. Today, this is measured via luminance or luminous intensity. Wikipedia has a good article on luminance.
It looks like this may possibly be a breakthrough, or possibly not. I remeber the electro-luminescent panels and devices that we had in the 1960's and wonder if it is a new implemantation of that technology. Those devices did provide a nice grale-free light, but not that much of it. I have no ideas about the relative efficiency, or lumens per watt. But the devices were very long-lived. I think that they were sort of expensive, as well. I have a couple of the inverter packages that were used by Chrysler for the EL instrument panels back in 1965, I think. They put out a very spikey waveform with a peak of almost 200V.
It would be interesting to find out about the performance of an actual prototype, as opposed to that of a single research sample device. That is the sort of information that would help to understand where this technology lies, on the development toward commercialization curve.
William, thanks for your comments. FIPEL (field-induced polymer electroluminescent) is the technology discussed here, invented by Carroll of Wake Forest U, the head of the research team mentioned in this article. Since FIPEL hasn't been commercialized yet, I suspect the EL you're talking about is not at all the same thing.
I'm not sure how much of the world's electricity budget goes to lighting - but I'll bet it's a lot. If we can get our light for less energy, I'm all for it. Just as long as it doesn't pose a health hazard in the bargain (mercury in CFL's - I can't believe those are even allowed as a consumer item.)
Scott, good point. I, too, hope that there aren't any hidden safety hazards associated with this new technology. Two things have disappointed me hugely about CFLs. First, the safety hazards associated with mercury, and second, the fact that they are meant to stay on for a long time, and not be switched on and off, as is usual in household, not office, use. That switching on and off lowers their lifespan tremendously. And of course, long lifespan was supposed to be part of the big draw in the first place--so you could amortize the much higher costs while you were saving energy.
The very fact that it has lasted ten years is fantastic. I'm use to screwing in a bulb and having it blow due to voltage surges. I went on the Wake Forest web site hoping to pull up specifications and none were there; i.e. watts, lumens, etc etc. This is a real breakthrough and certainly seems to be a viable alternative to what we have now in the market place. I think it is also gratifying to see nanotechnology applied to everyday uses. Great Article Ann and thank you for the information.
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