The organic light-emitting diode (OLED) continues to develop alongside the light-emitting diode (LED). This light source’s intriguing capabilities position it as a strong potential alternative to LEDs for certain applications.


The OLED source consists of a stack of organic, carbon-based thin films sandwiched between two electrodes and typically encased in plastic or glass. This allows a light source with a thickness well less than 2 millimeters but that can have a large area.


Today, OLED systems are typically manufactured as panels or panel assemblies that come with the housing and driver. Panel shapes include rigid squares (2 inches by 2 inches up to 12 inches by 12 inches), flexible squares (up to 12 inches by 12 inches), rigid bars (1 inch by 4 inches up to 4 inches by 12 inches), flexible bars (2 inches by 8 inches) and rigid round (2 inches up to 4 inches in diameter). The past few years have seen introduction of panels that are rigid or flexible, with larger sizes and new form factors.


Panel output is measured in light output (lumens) and brightness (candela). While a luminance of 3,000 candelas per square meter is considered suitable for applications where the light source is directly viewed, brighter panels are available. These panels emit up to 10,000 candelas per square meter for applications where the light source is not directly viewed.


Color output is considered good with a choice of correlated color temperatures typically ranging from a warm-toned 3,000K up to a cool-toned 4,000K, with some availability in 2,700K and 5,000K. Color rendering is available with a color rendering index (CRI) rating of 85 to 90.


Service life has seen a significant improvement over the past few years, increasing to 40,000 to 50,000 hours at L70. Service life and efficacy have improved an average 25 percent per year. 


Right now, OLED technology is behind the LED in terms of development, but it is advancing rapidly.


With LEDs’ strong advantages and intense focus in the lighting industry, other solid-state light sources must provide significant value to compete. The OLED, which has captured interest in the display and automotive applications, offers dramatic possibilities in lighting.


While the LED is a highly compact and directional point source, OLEDs offer a flat and diffuse area source. While LEDs are very bright and require shielding to prevent direct glare, OLEDs are very soft and, depending on the product, can be viewed directly without glare. LEDs produce internal heat during operation, requiring heat sinking. OLEDs do not, presenting potential to integrate the source with architectural materials and surfaces. Otherwise, luminaires using the two sources install similarly, use similar drivers and are dimmable. OLEDs also have the potential to be manufactured in custom shapes and as flexible and even transparent material.


Due to the cost of manufacturing, right now, OLEDs are still a pricey option at $200–500 per kilolumen at the panel level, although manufacturers say costs have come down 40 percent over the past year. Costs are expected to continue to decline rapidly, with one estimate projecting a decline to $20–50 per kilolumen within five years.


At this stage, OLED systems are primarily being installed to produce a “wow” factor in architectural lighting. Key applications include demonstration, custom and decorative projects. However, a number of OLED products recently have become available targeting specific applications such as pendant, sconce, task, display, signage and wayfinding.


Jeannine Fisher Wang, director, business development, Acuity Brands, believes that OLED technology will achieve a performance and cost level that will make it highly competitive with LEDs within five years, increasing adoption in general lighting.


Advances coming down the pike include new drivers and control protocols, a shift to flexible substrates, higher color rendering, and service life reaching 50,000 hours at L85. Solutions may be offered that integrate OLEDs into building materials and surfaces, even glass.


While performance of OLED systems will increase, Wang also predicts a coincident tenfold cost reduction at the panel level, driven largely by a manufacturing shift to flexible substrates. She said that, for some luminaire types, such as sconces, OLEDs are already cost competitive with LEDs and, within three to five years, may be competitive with LED troffers and linear pendants.


The LED revolution is really the solid-state lighting revolution, with more than one choice on the menu. The emergence of OLED technology will create new possibilities for lighting design. If successful, OLEDs will become part of the transformation of the built environment and the lighting industry.