A Lawrence Berkeley National Lab research team has discovered a new way to process white OLEDs for solid-state lighting.
OLEDs based on organic and/or polymer semiconductor materials can cover large-area displays or panels using low-cost processing techniques. Single-color OLED displays are already available commercially. A mix of red-, green- and blue-emitting materials can be used to generate white light, but these bands of color often interact with one another, degrading device performance and reducing color quality.
Using polymer nanoparticles to house light-emitting inks, scientists at the Molecular Foundry have made a thin film OLED using iridium-based guest molecules to emit various colors of visible light. The polymer nanoparticle surrounding a guest light-emitter isolates guest molecules from one another. Each guest can then emit light without interactions with neighboring nanoparticles, resulting in white light.
“This simple and bright approach to achieving nanoscale site isolation of phosphors opens a new door for facile processing of white OLEDs for solid state lighting,” says Biwu Ma, a staff scientist with the Molecular Foundry’s Organic Nanostructures Facility. Ma and his colleagues plan to vary the ratio of each color nanoparticle in the OLED to enhance efficiency and brightness.
A paper reporting this appears in the journal Nano Letters.