Until now, no good host materials were available to transport the change to blue phosphorescent light emitters. Without an efficient blue component, it is not possible to generate the high-quality white light required for indoor lighting. The PNNL team is linking small organic molecules together using inorganic phosphine oxide connecting units to make larger molecules that transport charge, but do not interfere with the blue light emission process. Look for developments in lighting in the next decade.
New Materials for High-Efficiency Organic Solid-State Lighting Developed
Published In September 2006
An organic molecule developed by Pacific Northwest National Laboratory (PNNL) scientists may significantly improve the efficiency of organic solid-state lighting. Direct conversion of electricity to light in solid-state thin films of organic molecules occurs in organic light emitting devices, which can be far more efficient than conventional incandescent light bulbs.
In an organic light emitting diode (LED), molecules harvest positive and negative charged carriers from oppositely charged electrodes to create excitons, which collapse to give light emission. By using organometallic phosphors, a photon can be emitted for every electron used, so there is no wasted current.