Enhanced Light Extraction from Bottom Emission OLEDs by High Refractive Index Nanoparticle Scattering Layer

Abstract

High refractive index nanoparticle material was applied as a scattering layer on the inner side of a glass substrate of a bottom emission organic light emitting diode (OLED) device to enhance light extraction and to improve angular color shift. TiO2 and YSZ (Yttria Stabilized Zirconia; Y2O3-ZrO2) were examined as the high refractive index nanoparticles. The nanoparticle material was formed as a scattering layer on a glass substrate by a coating method, which is generally used in the commercial display manufacturing process. Additionally, a planarization layer was coated on the scattering layer with the same method. The implemented nanoparticle material and planarization material endured, without deformation, the subsequent thermal annealing process, which was carried out at temperature ranged to 580 °C. We demonstrated a practical and highly efficient OLED device using the conventional display manufacturing process by implementing the YSZ nanoparticle. We obtained a 38% enhanced luminance of the OLED device and a decreased angular color change compared to a conventional OLED device.

<p>Mechanical Properties of Nanohybrid Resin Composites Containing Various Mass Fractions of Modified Zirconia Particles</p>

“…However, the translucence and refractive index of zirconia particles are not desirable compared with those features of silica particles. 17,26 It remains unclear whether the translucence of the resin would be affected as the nano-zirconia filler content increases. Moreover, resin materials with low translucence and a high refractive index are insufficiently cured by a light-cured initiator system.…”

Disordered Nano‐Hemisphere Molybdenum Trioxide for Enhanced Light Out‐Coupling in Organic Light‐Emitting Diodes

“…Initially, we determined an OLED structure based on an exciplex, as shown in Figure , which not only maintained high‐efficiency electrical properties but also reflected the value of excellent external light coupling rate to avoid excessive internal losses from interfering with the light extraction effect of M‐NSL. [ 30–32 ] The key features of the emitting layer are the positioning of red phosphorescent material and the combination of blue phosphorescent material with a carefully selected host material (as shown in Figure 4), the transportation of charge within the highest occupied molecular orbital (HOMO), and the lowest unoccupied molecular orbital (LUMO) of different structural layers. The triplet energy of all materials essentially defines the exciton distribution and consequently influences the emission spectrum and efficiency, including PE, CE, and EQE.…”

Coupled Superhydrophilic PMMA Film with Inverted Pyramid Microstructures for Antireflection and Antifogging Properties

“…When silica sol is sprayed onto the P-R sample, a superhydrophilic nano-SiO 2 film will be formed on the top. On the one hand, air will enter the nanoparticle layer, which declines the refractive index of the top layer, and a lower refractive index contributes to augmenting transmission of the film [22,23]. On the other hand, the optical properties of the film are affected by the interlayer particle structure [24]; the granular structure of the top layer not only causes the incident light to be scattered at different angles, but also concentrates the incident light.…”