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.
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.
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?
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.
New versions of BASF's Ecovio line are both compostable and designed for either injection molding or thermoforming. These combinations are becoming more common for the single-use bioplastics used in food service and food packaging applications, but are still not widely available.
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