LEECs are a new approach to produce cheap lighting devices. The devices only consist of one layer of charged compounds sandwiched between the electrodes. Researchers from the Basel university announced some major technical advances about the LEEC lighting technology.

We are working on charged Iridium complexes suitable for these applications. Such compounds are known for high efficiency and are therefore used only at low concentrations so the swiss researchers.

The present invention relates to a light-emitting electrochemical cell comprising at least two electrodes, and an electroluminescent material arranged between said two electrodes, wherein the electroluminescent material comprises a charged metal complex. It also relates to a method for manufacturing light-emitting electrochemical cells, and to substances which may be used as electroluminescent substances.

BACKGROUND OF THE INVENTION Due to rapid progress in the development of organic light-emitting materials, devices based on these materials, called PLEDs and OLEDs (polymer and small-molecule organic light-emitting diodes), are entering the display market. In principle these materials can also be used for large-area lighting applications, which is an important market for the near future. However, the main disadvantages of using PLED/OLED devices for large-area lighting are: - A low-workfunction metal such as Ba or Ca has to be used as cathode to make injection of electrons possible. These metals are very easily oxidized, which shortens the lifetime and requires special packaging of the device. the electroactive layer has to be thin (-70 nm) because the current, and thus the light output, decreases dramatically with increasing thickness. The processing of large- area layers of such thickness, avoiding shorts and light inhomogeneities, is very difficult. A very promising alternative to PLED/OLED particularly for lighting applications is the light-emitting electrochemical cell (LEEC) (0). A LEEC does not need a low-workfunction metal electrode and thicker electroactive layers can be used, while keeping the operating voltage low. The operating mechanism is based on the presence of mobile ions.
via OLED.at