Study on Working Principle, Structure, Enhancement Technology, and Applications of Organic Light-emitting Diodes

Abstract

Nowadays OLEDs outperform normal LEDs in terms of ease-processing, flexibility, skinniness, lightweight, and manufacturing cost. However, there is still much room to improve in terms of materials, efficiency, and longevity. Improving the performance of OLEDs has become the most popular research area. In order to make full use of excitons after recombination of carriers, phosphorescent OLED has been proposed. Recently, there is a gradual trend for phosphorescent OLEDs to be replaced by TADF OLEDs, as these TADF OLEDs can not only exhibit 100% internal quantum efficiency and are cheap to produce because they do not contain precious metals. At the same time, TADF OLEDs are considered to have more room for development especially in the aspect of longevity and color. Therefore, more researches are still needed to solve the blue OLED problem because compared to other colors, such as red and green OLEDs, blue OLEDs still have a big gap in stability and efficiency. In this work, the history of OLEDs, their working principle, the technologies that have been improved, and the cross-border derivative applications were studied.