Scientists’ discovery could mean less-expensive smartphones, TVs

Iridium has been generating light and color for screens on smartphones and TVs, but it’s the rarest metal on Earth; USC scientists found a way to make copper work

USC che­mists have found a che­a­per way to light up smart­pho­ne and TV screens, which could save manu­fac­tu­rers and con­su­mers money without affec­ting visu­al qua­li­ty. Cop­per is the ans­wer, accord­ing to their stu­dy, published Fri­day in the jour­nal Sci­ence.

The cur­rent tech­no­lo­gy that is in every Sam­sung Gala­xy pho­ne, high-end Apple iPho­ne and LG TV reli­es on iri­di­um com­pounds for the colors and light on orga­nic LED screens,” said Mark Thomp­son, a che­mist at the USC Dorn­si­fe Col­le­ge of Let­ters, Arts and Sci­en­ces. “We have been using iri­di­um becau­se you get a high­ly effi­ci­ent light emis­si­on, but it is the rarest natu­ral­ly occur­ring ele­ment on Earth,” Thomp­son said. “One of our chal­len­ges has been to come up with an alter­na­ti­ve that is more abundant.”

Pri­or attempts to gene­ra­te a cop­per-based orga­nic LED, or OLED, fai­led. The cop­per com­ple­xes in tho­se stu­dies had wea­ker struc­tures. The mole­cu­les were unsta­ble, with shorter life­ti­mes than the iri­di­um com­pounds.

Iridium’s link to dinosaurs

Cop­per defi­ni­te­ly sol­ves that pro­blem sin­ce it is a plen­ti­ful metal world­wi­de. Iri­di­um, on the other hand, is found in only a few pla­ces — most­ly South Afri­ca and parts of Asia. The most wide­ly accep­ted hypo­the­sis that exp­lains iridium’s scar­ci­ty and its orig­ins is that it tra­v­eled here on a mete­or — the same one that wiped out the dino­saurs 65 mil­li­on years ago. Unless ano­t­her mete­or like that hits Earth, iri­di­um will con­ti­nue to dwind­le in sup­ply. Demand for it is only increa­sing as smart­pho­nes, TVs and other devices that fea­ture LED screens gain popu­la­ri­ty. OLEDs have come to replace LED LCD screens. In an OLED screen, each pixel gene­ra­tes light, while in the LCD screens, pixels are illu­mi­na­ted by an LED back­light.

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