OLED Materials for Polarized, Tunable Color (and White) Emission

Brief Description
Brief Description:
This is a new class of organic light emitting diode (OLED) materials which are capable of producing efficient polarized light in particular colors (blue, green, red) as defined by the chemical structure of the materials selected. 

Because this technology provides an efficient source for the polarized light, it could be used in power-saving light sources in liquid crystal displays (LCD), which account for the bulk of flat panel display market today. Current LCDs use absorptive polarizers and color filters, which limit efficiency of the back-light to about 4%.  The materials of this invention would enable much more efficient power utilization.  Linearly polarized OLEDs of this invention are also potentially useful in electroluminescent displays with reduced glare and increased contrast, as well as in projection displays and in stereoscopic imaging systems.

The invention describes OLED devices with a light-emitting layer capable of producing polarized light,.  The light-emitting layer includes a fluorene or mixture of oligomeric fluorenes.  In contrast to p-conjugated polymers reported in the past, the mono-disperse conjugated oligomers are characterized by a well-defined and uniform molecular structure and by chemical purity (via recrystallization or column chromatography).  The oligomers can be therefore be produced with better chemical purity and morphology and, because of their mechanical properties, they tend to be easier to coat uniformly.  Full color and white-light OLED devices have been built with these materials, with a polarization ratio up to 27 and a luminance yield up to 1 cd/A, a turn-on voltage as low as 6V and voltage-independent chromaticity.
Patent Information:
Title Country Patent No. Issued Date
Polarized Organic Light-Emitting Diodes Using Monodisperse Glassy-Nematic Oligofluorenes United States 7,037,599 5/2/2006
For Information, Contact:
John FahnerVihtelic
Senior Licensing Manager
University of Rochester
Shaw-Horng Chen
H. Sean Culligan
Yanhou Geng