29‐3: Improving Lateral Leakage Current in OLED Pixels by New Hole Transport Materials: Resolving the Crosstalk Issue

Abstract

State‐of‐the‐art displays based on organic light emitting diodes for smartphones and tablets consist of side‐by‐side arrangements of red, green, and blue sub‐pixels. In the blue emissive layer, fluorescent materials are used, whereas red and green are realized by phosphorescence. This difference in materials is reflected in very different current‐voltage characteristics which can lead to current flowing in the lateral direction from the active blue pixel to neighboring non‐active red/green sub‐pixels causing undesired emission. This effect is especially dominant in the low luminance regime, thereby reducing color purity significantly. In this paper we introduce recently developed hole transport materials (HTM) which significantly suppress such lateral leakage current thereby preventing sub‐pixel crosstalk without compromise in other device parameters like lifetime and power‐consumption. Applicability of such materials is shown in the combination of hole‐injection‐layer (HIL, with p‐dopant) and hole‐transport‐layer (HTL).