OLED Planarization Layer with Perfluorocyclobutanes
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Solution Overview
Problem
Organic light emitting diodes (OLEDs) with non-flat surfaces or non-uniform thicknesses experience interlayer mixing and reduced luminous efficiency during printing processes, leading to decreased performance and shorter operational lifetimes.
Innovation Solution
Incorporating a planarization layer with perfluorocyclobutanes (PFCBs) to create a flat surface for the organic light emitting layer, ensuring uniform contact and reducing mixing between layers, while using a multilayer structure including hole and electron transport layers to enhance charge mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a printing process is used to form organic layers, then manufacturing simplicity and cost-effectiveness are improved, but layer uniformity and flatness deteriorate leading to interlayer mixing
Solution Approach 1:
The organic light emitting diode is divided into multiple functional layers (hole injection layer, hole transport layer, organic light emitting layer, electron transport layer, electron injection layer) with distinct materials and properties. Each layer is formed separately through the printing process, allowing independent optimization of printing parameters for each layer to achieve both manufacturing simplicity and layer uniformity.
Solution Approach 2:
The hole transport layer and electron transport layer act as intermediary layers between the hole injection layer and the organic light emitting layer, and between the cathode electrode and the organic light emitting layer, respectively. These intermediary layers provide flat interfaces that prevent interlayer mixing while maintaining the benefits of the printing process.
2Adaptability or versatility
If layers are stacked with non-flat surfaces, then manufacturing flexibility is improved, but charge transport control deteriorates and luminous efficiency decreases
Solution Approach 1:
Each layer is designed with specific local properties: the hole injection layer has high hole injection capability, the hole transport layer has high hole mobility and flat surface, the organic light emitting layer has appropriate HOMO-LUMO levels, the electron transport layer has high electron mobility and flat surface, and the electron injection layer has low work function. This local optimization ensures both manufacturing flexibility and reliable charge transport control.
Solution Approach 2:
The patent optimizes various parameters including material selection (different organic compounds for each layer), thickness control (controlling the thickness of each printed layer), and surface morphology (ensuring flat surfaces in transport layers). These parameter changes enable reliable charge transport while maintaining manufacturing flexibility through printing processes.
3Productivity
If layer thickness is non-uniform, then printing process speed is improved, but interlayer mixing occurs and device lifetime is reduced
Solution Approach 1:
The hole transport layer and electron transport layer are designed to be formed with flat surfaces as a preliminary step before forming the organic light emitting layer. This preliminary action of creating flat interfaces prevents interlayer mixing during subsequent printing operations, allowing faster printing speeds without compromising device lifetime. The flat surfaces are achieved through careful selection of printing parameters and material properties for these transport layers.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves a uniform stacked structure, reduces color mixing, and improves the operational lifetime and luminous efficiency of OLEDs, even when formed through printing processes.
Implementation Method 1
the planarization layer being configured to transport holes from the first common layer to the organic light emitting layer
Implementation Method 2
an organic light emitting diode having a uniform (or substantially uniform) layer stacked structure
Data Source
AI summary
Provided are an organic light emitting diode, an organic light emitting display panel including the same, and a method of manufacturing the organic light emitting display panel. The organic light emitting diode includes: an anode electrode on a substrate; a first common layer on the anode electrode to inject or transport holes and having a non-flat side; an organic light emitting layer on the first common layer; a planarization layer on the non-flat side of the first common layer, providing a flat side to the organic light emitting layer, transporting holes from the first common layer to the organic light emitting layer, and including perfluorocyclobutanes (PFCBs); and a cathode electrode on the organic light emitting layer.