Micro Technology

Electroluminescent inorganic materials are well known since several years and inorganic based light emitting diodes (LED) have been commercially available since the early '60s.
Electroluminescence from organic materials has been discovered in the same period, but the operating conditions required for many commercial applications and for the development of Organic Light Emitting Diodes (OLED)s and Polymer Light Emitting Diodes (PLED)s have been reached only in the '80s.

Monochromatic screens based on these organic devices have been introduced on the market in 1997.
In an organic light emitting diode, a thin layer of organic material is cast between two electrodes and one of them has to be semitransparent to permit the visible output of light.

A highly conjugated polymer is layered as thin film on the top of ITO (Indium Tin Oxide) a semi-transparent, semiconducting material that behave as the anode.
On the top of the polymeric layer is evaporated under high vacuum a metallic contact, which works as the cathode.
When an external voltage is applied to the electrodes, transport carriers with opposite charges (electrons and holes) are injected in the organic emissive layer and move into it under the action of the external applied electric field (>10⁵ V/cm).
The further recombination of electron and holes within the bulk of the polymer permits the emission of light.

Centro Laser has reached a good level of knowledge in the fabrication of those devices.
Sputtering ITO deposition, casting of organic materials via spin coating or thermal evaporation (for insoluble polymers) and deposition of metallic contacts have been diffusely investigated.