Using an embedded nanocomposite layer to increase color-conversion efficiency of organic light-emitting diodes

• TiO2 nanoparticles mixed with fluorescent dyes could be used to increase the absorption of dyes in color-conversion layer.
• The EL spectra with different viewing angles are close to the ideal Lambertain curve.
• WOLEDs with a nanocomposite color-conversion layer achieved high efficiencies and stable white-light emission.

Down-conversion white organic light-emitting diodes (WOLEDs) have a significant advantage in generating stabilized white-light emissions, but still have room for further improvement in terms of color-conversion efficiency. We demonstrated that TiO2 nanoparticles mixed with fluorescent dyes could be used to increase the absorption of dyes and thus boost the efficiency of color-conversion. WOLEDs with a nanocomposite color-conversion layer achieved high efficiencies of 12.3% (22.9 cd/A and 22.5 lm/W) and stable white-light emission. In addition, the EL spectra with different viewing angles are close to the ideal Lambertain curve. These outcomes indicate that the nanocomposite-based color-conversion possesses great potential for use in display and lighting applications.

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