Recent research of materials for emissive layer of OLED

Abstract

As time has gone on, a lot of changes in display technology have taken place. Organic light-emitting diode (OLED) is the one of the many types of display technology. They have attracted many interests in the academic filed and commercial worlds, and developed rapidly since their earliest introduction. They are now highly regarded and used in the display and lighting industries due to a number of promising characteristics, such as environmentally friendly, high energy efficiency, large area, light weight, and thin shape. Among various light emitting materials, polymers have higher glass transition temperature. Therefore, polymer-based OLEDs exhibit higher stability and have received wide attention. The development of OLED devices can be divided into three main generations of emitter materials based on the technique of the emissive layer of OLEDs. The first generation of OLED is fluorescent OLED (FOLED), the second generation is phosphorescent OLED (POLED), and the third generation is thermally activated delayed fluorescence (TAFD). In this article, device structure, mechanism and development of polymer-based OLEDs are introduced. Specifically, working principles and materials of the three generations are presented with a focus on TADF-based OLEDs. In addition, their device performances including quantum efficiency and lifetime are compared quantitatively.