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Photo credit: Chuck "Caveman" Coker

Thomas Edison may have thought he perfected the light bulb in 1879, but many countries are phasing out traditional incandescent light bulbs in favor of energy-saving products. You are likely familiar with compact fluorescent lights (CFLs) and light-emitting diodes (LEDs), but a new source of lighting has also emerged: organic light-emitting diodes (OLEDs).

Based in the Netherlands, Philips has produced a strip of lighting made from OLEDs that is able to be powered directly from a mains electricity supply, which is a bona fide breakthrough in the lighting business. This will eventually mean that cumbersome power electronics and transformers won’t have to be used with OLED lights anymore—which will reduce costs, simplify design and allow them to be fitted into more products. While mains-powered CFLs and LEDs have turned into direct plug-in replacements for incandescent bulbs in recent years, OLEDs will serve a different purpose.

Incandescent bulbs cost around 50 cents and burn for 1,000 hours, while CFLs cost around $3, use up to 75% less power and last much longer. LED lights cost more still, but are even more efficient than CFLs. Osram, a division of Germany’s Siemens, recently introduced a LED lamp shaped like a conventional 60-Watt light bulb. Called the Parathom Classic, it retails in Europe for around $64, uses 90% less power than an old-type bulb and boasts an average life of 25,000 hours.

Adopting CFLs does take some get used to; it takes these bulbs more time to reach their maximum illumination and the light they emit is different than the warm glow produced by an incandescent bulb. An incandescent bulb uses electricity to heat up a wire filament sitting in a low-pressure inert gas encased in glass, while a CFL uses electricity to stimulate mercury vapor. The mercury vapor produced an ultraviolet light that causes a phosphor coasting on the inside of the bulb to grow—but there is some environmental concern over the disposing of the mercury once the bulbs wear out.

LEDs work by applying a current to two layers of semiconductor, thus creating a flow of electrons and releasing energy in the form of light. LEDs used to only be used as the red indicator lights in electronic equipment, but white-light LEDs are now commonly used in torches and lamps and on cars. Although the light from LEDs can be intense, new technology allows them to be dimmed and tuned to produce different colors (including one that resembles natural daylight).

OLEDs are made from layers of organic material which illuminate when a charge is applied to them. That charged used to have to be a low-voltage direct-current source (such as from batteries) as opposed to the alternating higher-powered currents delivered over the mains. LEDs are currently used as displays in products like mobile phones and come televisions, but lighting versions have begun to emerge.

OLEDs using in lighting will be different because they can be made very thin and flexible, and an OLED light could be made into the material which forms the shade of the lamp itself, while CFLs and LEDs can replace the bulb in a lamp as a single bright point of light. Philips Lighting’s Dietrich Bertram says that a OLED panel could eventually form part of a ceiling or wall (transparent OLEDs can even be put into windows) and is hopeful that mains-powered OLEDs will be commercialized soon. OLEDs will be efficient and capable of producing a spectrum of light similar to natural daylight with an operating life of approximately 10,000 hours, says Bertram, adding that they will be sold at designer process at first, like LEDs.

Read more about low-energy lighting here.