The technology behind everyday lighting has advanced rapidly – from incandescent, to CFL, to LED. The next advancement – OLEDs still have a long way to go before they become totally ubiquitous. Although many mobile devices and televisions use OLED technology, it still has too many disadvantages to use for central lighting. But thanks to a recent discovery using platinum, OLED technology has advanced significantly.
Unlike LEDs which use crystal semiconductors to produce light, OLEDs use polymer chains that glow when they are stimulated with an electrical current. However, they cannot create white light on their own – at least not without complex and expensive engineering. The common trick engineers use to get OLEDs to project white light is by making them combine red, green, and blue light. Of course, the extra lights mean that more energy is used.
Professor Valy Vardeny of the University of Utah and colleagues have created a new formula of OLED polymer that uses platinum atoms to create white light more easily. Usually, polymers have two electronic states – single and triplet. When the polymer is stimulated, it enters the singlet state and emits blue light. But, stimulating the polymer into a triplet state to create the other colors of light in the spectrum is more difficult. Vardeny’s new platinum-incorporating polymer is much easier to get into a triplet state – making color mixtures and energy transfers unnecessary for creating white light.
In simpler terms: if blue, red, and green OLEDs represent a computer, telephone, and camera, then an OLED made with this new polymer is a smartphone – combining the features of all three.
Once again, precious metals are contributing to green technology to make the world a better place.