Organic Electro-Luminescence

Long lifetime and high efficiency achieved by SEL's original technology.
Aiming at providing images with vivid colors.

Organic Light-Emitting Diode (OLED)

Now, OLED displays (organic EL displays) are the main stream of displays as well as LCDs, and have been actively developed to pursue higher performance: high efficiency, long lifetime, high resolution, and wide color gamut. Moreover, an attempt to apply an organic EL to lighting has been made.

To realize high-performance OLED displays and lighting, it is necessary to develop organic EL materials. SEL has been developing original organic EL materials and achieved high-efficient and long-life devices using TTA and ExTET® technologies. In addition to the development for original materials, we are also studying and fabricating original device structures to conform to BT.2020 standard (reproducing about 99.9% of colors in the natural world), which has recently been drawing attention, for vivid colors.

▲Photoluminescence demonstrated in solution

Organic EL materials development
Higher-Brightness and Longer-Life Technology

SEL’s original technology, ExTET®

We have developed a phosphorescent device where an electron-transport host material and a hole-transport assist material form an exciplex in a light-emitting layer and energy is transferred from the exciplex to a phosphorescent dopant, which leads to light emission. We call this technology Exciplex-Triplet Energy Transfer (ExTET®). This technology enables both low driving voltage and long lifetime as well as high efficiency.

Energy transfer diagram of ExTET

TTA increases emission efficiency of fluorescent device

In a current-excitation device, there is a 25 % probability (internal quantum efficiency) of producing a singlet exciton leading to fluorescence and 75 % probability of producing a triplet exciton. Thus the emission efficiency of a fluorescent device is lower than that of a phosphorescent device but if an increase in the probability of producing a singlet exciton by some method would increase the emission efficiency. One method is TTA, which is a phenomenon where a singlet exciton is formed in a light-emitting layer by mutual interaction of triplet excitons. We have found a device structure to enhance the probability of producing TTA and developed a fluorescent device with high emission efficiency.

Energy diagram of TTA

OLED fabrication

We have been developing OLEDs as well as materials in our laboratory to pursue optimal device structures for realizing high-performance OLED displays.

▲OLED (Left: red, Right: green)

OLED display development

Jump to OLED Display page

Turning on the light when the room is dark.
Such simple daily actions give us hints for invention.

Organic EL Lighting Panel

The mainstream in lighting is transitioning from incandescent and fluorescent lights to LEDs and organic EL lighting, which provide low power consumption and longer life. In this transition, our focus is on organic EL lighting and we envision a future with more comfortable lighting. Organic EL lighting has low power consumption and long life, and also has excellent color rendering properties which produce light that is close to natural light. It is also favorable environmentally and in design ability, as it is mercury-free, has a surface light source, and is thin, light, and flexible.

We are developing light boards and flexible lighting with the goal of practical application, and we are also striving to improve power efficiency, lifetime, and color rendering properties of organic EL lighting, with the goal of popularizing organic EL lighting.

* ExTET is a registered trademark of Semiconductor Energy Laboratory Co., Ltd. (Japanese trademark registration No. 5666910).