Organic electroluminescent diodes. Technology

First studied in the 1960s, organic electroluminescence has attracted considerable interest since 1987, when the first thin-film components deposited by evaporation were presented. Two technological avenues were then developed: molecular materials and luminescent polymers. Many of these materials, generally referred to as organic semiconductors, emerged from the development of xerography and conductive polymers in the 1970s and 1980s. While organic light-emitting diodes (OLEDs) based on molecular materials have been much studied in Asia, polymer technology has been of greater interest to European laboratories. The first aim of this article is to situate organic electroluminescence in the specific context of display and visualization. The operating principle of OLEDs, the materials used and the implementation techniques will then be presented. While the short life of the components initially appeared to be an obstacle to their industrial production, we will see that the development of an appropriate technology has made it possible to solve this problem. A review of industrial realizations will show the current superiority of OLED technology linked to molecular materials, and the potential of flexible components. The development of OLED technology has paved the way for organic electronics, with organic semiconductors also enabling the production of transistors, photovoltaic cells, sensors and more. Organic technology, which uses relatively simple, low-cost thin-film deposition processes that are compatible with flexible polymer substrates, looks very promising.