Although the latest Nobel Prize in Physics has established light-emitting diodes (LEDs) as the best source of artificial light, scientists are still searching for even better bulbs. And a team of scientists from the University of Tohoku (Japan) seems to have found an ingenuity that surpasses them: it is a new type of flat light source made with carbon nanotubes, very efficient and with very low energy consumption: about 0.1 watts for every hour of operation, that's about a hundred times less than LEDs.
Carbon-based electronics, especially carbon nanotubes (CNTs), are emerging as the successor to silicon for the manufacture of semiconductor materials. This material may enable a new generation of low-cost, low-power, bright devices that could challenge the dominance of LEDs.
In their research, published in the 'Review of Scientific Instruments', Japanese scientists have worked on optimizing this device, based on a phosphor screen and a single wall of highly crystalline carbon nanotubes (SWCNTs), as electrodes in a structure. diode. "It's like a field of tungsten filaments reduced to microscopic proportions," the article explains.
Experts have assembled the device with a liquid mixture of an organic solvent combined with a soap-like chemical known as a surfactant. The mixture is "painted" over each positive electrode or cathode, and the surface is scratched with sandpaper to form a panel of light capable of producing a large, stable and homogeneous stream of emissions with low energy consumption.
"Our simple panel could achieve a high light efficiency of 60 lumens per watt, which represents excellent potential for a lighting fixture with low power consumption," said the study's lead author, Norihiro Shimoi.
Experts have explained that this new device has a luminescence system that works more like cathode ray tubes, with carbon nanotubes acting as cathodes, and a phosphor screen in a vacuum cavity that acts as the anode.
Under a strong electric field, the cathode emits tight, high-speed beams of electrons through its sharp nanotube tips, a phenomenon called field emission. The electrons then fly through the vacuum in the cavity, hitting the phosphor screen.
"We have found that a cathode such as a single wall of highly crystalline carbon nanotubes and an anode with the phosphor screen improve the structure and obtain good brightness homogeneity," Shimoi pointed out.