Edison’s brilliant idea, the metal filament light bulb , has been making its way into technology museums for some time. Their problem is that only around 2-3% of the electrical energy necessary for their tungsten or tungsten resistors to become incandescent (the filaments of these lamps reach a temperature of 2,700 degrees Celsius) is transformed into visible light; the rest is dispersed as heat. Hence, much more efficient compact fluorescent lamps and LED technology have progressively replaced it.
But let’s not give up the old incandescent lamp for dead yet, because researchers at the Massachusetts Institute of Technology (MIT) have been determined to restore its warm glow in our homes thanks to nanotechnology. Called photonic crystal , the invention of these experts consists of a structure made with very fine alternating layers of glass, tantalum oxide and silicon dioxide that acts both as a mirror and a filter. On the one hand, it lets through the visible light emitted by the tungsten resistance, and on the other, it reflects infrared radiation, which is reabsorbed and reused to generate more luminosity.
MIT experts have also redesigned the filament , which instead of offering its traditional twisted appearance forms a kind of sheet. Thus, it has been possible to increase its surface area and, consequently, its ability to reabsorb infrared radiation. According to the researchers themselves in Nature Nanotechnology, their lamp reaches an efficiency of 6.6%, practically tripling that of conventional bulbs, although they trust that they can exceed 40% if they add new materials and improve the structure of their photonic crystal.
