Raziskovalci so prvič ustvarili-svetleče diode (LED) na lahki fleksibilni kovinski foliji.
Inženirji na državni univerzi Ohio razvijajo LED diode na osnovi folije za prenosne ultravijolične (UV) luči, ki jih lahko vojaki in drugi uporabljajo za čiščenje pitne vode in sterilizacijo medicinske opreme.
In the journal Applied Physics Letters, the researchers describe how they designed the LEDs to shine in the high-energy "deep" end of the UV spectrum. The university will license the technology to industry for further development.
Globoko UV svetlobo že uporabljajo vojska, humanitarne organizacije in industrija za aplikacije, ki segajo od odkrivanja bioloških dejavnikov do sušenja plastike, je pojasnil Roberto Myers, izredni profesor znanosti o materialih in inženiringu v državi Ohio.
Težava je v tem, da so običajne globoke{0}}UV žarnice pretežke, da bi jih bilo enostavno prenašati.
"Right now, if you want to make deep ultraviolet light, you've got to use mercury lamps," said Myers, who is also an associate professor of electrical and computer engineering. "Mercury is toxic and the lamps are bulky and electrically inefficient. LEDs, on the other hand, are really efficient, so if we could make UV LEDs that are safe and portable and cheap, we could make safe drinking water wherever we need it."
He noted that other research groups have fabricated deep-UV LEDs at the laboratory scale, but only by using extremely pure, rigid single-crystal semiconductors as substrates—a strategy that imposes an enormous cost barrier for industry.
Nanotehnologija na osnovi folije- bi lahko omogočila obsežno-proizvodnjo lažjih, cenejših in okolju prijaznejših globokih-UV LED. Toda Myers in doktorski študent znanosti o materialih Brelon J. May upata, da bo njihova tehnologija naredila nekaj več: spremenila nišno raziskovalno področje, znano kot nanofotonika, v uspešno industrijo.
"People always said that nanophotonics will never be commercially important, because you can't scale them up. Well, now we can. We can make a sheet of them if we want," Myers said. "That means we can consider nanophotonics for large-scale manufacturing."
Ta novi razvoj deloma temelji na dobro-uveljavljeni tehniki rasti polprevodnikov, znani kot epitaksija z molekularnim žarkom, pri kateri se uparjeni elementarni materiali usedejo na površino in se-samoorganizirajo v plasti ali nanostrukture. Raziskovalci iz zvezne države Ohio so uporabili to tehniko za gojenje preproge iz tesno zapakiranih žic iz aluminijevega galijevega nitrida na kosih kovinske folije, kot sta titan in tantal.
The individual wires measure about 200 nanometers tall and about 20-50 nanometers in diameter—thousands of times narrower than a human hair and invisible to the naked eye.
V laboratorijskih testih so nanožice, vzgojene na kovinskih folijah, zasvetile skoraj tako močno kot tiste, izdelane na dražjem in manj fleksibilnem enokristalnem siliciju-.
Raziskovalci si prizadevajo, da bi nanožične LED diode postale še svetlejše, nato pa bodo poskušali gojiti žice na folijah iz bolj običajnih kovin, vključno z jeklom in aluminijem.
