New nano-technology create perfect absorber

Director David R. Smith recently interviewed with Frank Grotelüschen of The interview focuses on Smiths' recent Nature publication and nanocubes in respect to lightbulbs. The full text is translated from German to English below.

"Silver than light swallowers

New nano-technology create perfect absorber

By Frank Grotelüschen

Technik. - Because of their lousy energy efficiency the EU Commission has declared the lightbulb looking redundant, because of their pleasant light are the remaining stocks since then hoarded of numerous lovers. A new coating from U.S. laboratories could make that Auslaufmodell are becoming competitive again. In "Nature", researchers switch before a method, with the itself light of targeted lets absorb than previously.

Schön eckig and made ​​of pure silver - so see from the dice, experimented with whom David Smith. Valuable however they are not. For this purpose namely they are simply too small.

"75 nanometers or so." 75 nanometers, 100,000 times smaller than a sugar cube. Recognize to the Winzlinge are only accessible through the Special Microscope: On the picture lie hundreds of nanocubes around like thrown down randomly, all with approximately the same distance. This nano-work of art has Smith, chemist at Duke-university in the USA, created with his new method: First he created a wafer-thin gold layer, which he has then via covered with a fine plastic-film, of these acts as a dividing layer. On these separating layer of the researchers was steaming then on the Silver Würfel. The result is spectacular, and in the truest sense of the word.

'Actually strew the dice the light very strongly. you should thereby be well visible. Also the gold layer below the cubes the light reflects very well. We have but managed it that itself the reflected light from the tumbling dice and the of the gold layer extinguishes exactly The result:. the perfect light absorption '. Important for that is the distance between cubies and gold layer. Only if he possesses a certain value, themselves delete the lightwaves from Cubes mades and gold layer mutually exclusive. These optimal distance but the researchers can switch precisely depending by making an vary the thickness of the separating layer. A trick that's folds however only for single colors, not but for white light, ie the entire light spectrum. After all: The color that should are swallowed, can David Smith choose freely: 'Yes, that is possible You can the color that is absorbed, adjust either features by we alter the size the Silver Würfel same time, we change their distance to the gold layer.. , in which we make the separation layer thinner or thicker. Thus we can manufacture light swallowers, absorb the each desired color from among the visible spectrum, or also out of the infrared-range. ' light absorber with comparable abilities must currently are manufactured with lithographic techniques, similarly to computer chips. These procedures but are complicated and expensive.

These nanocubes of David Smith should da, so the hope, be much cheaper. Because basis are chemical, use methods that they today employs already in mass manufacturing. And what applications promises the method? Well, says Smith, they could of the good old incandescent lamp to create that Come-back. "One could the filament contained hitherto heat except light yes above all, ie infrared radiation, emits, coating it with silver dice. These dice would the thread literally to compel, to give off more visible light and hardly still heat. " Today, the efficiency a light bulb lies with straight times five percent. You converts just a a twentieth of the electricity supplied into light, the rest dissipates as heat. It would prove possible, boosting the efficiency with Help the Silver Würfel significantly, could the lightbulb be again socially acceptable. Conceivable but also efficient thermocouples, the heat would can directly transform into current: With the nanocubes they could be informed by vote to a quite specific temperature, approximately around the waste heat of an engine to take targeted advantage.

Until then however, says David Smith, there are still some work in laboratories. 'gives When chemistry it still problems, approximately in the manufacture the Silver Würfel. And Although we would the dice gladly can be prepared in such, that all the same size possess, eg all are exactly 75 nanometers in size So far the size fluctuates still too strongly -. still are too many 80-nanometer-dice thereby'".

 For an Audio Link in German to the transcribed interview above please click here.