Organic Electronic Device Charge Injection Layer
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Solution Overview
Problem
Existing organic electronic devices face challenges with high operating voltages and instability due to the use of low work function metals, which are reactive, difficult to process, and require rigorous exclusion of air, leading to reduced efficiency and lifetime.
Innovation Solution
The development of organic electronic devices incorporating a chemical compound with a specific formula, capable of acting as a dopant or charge injecting material, which provides improved thermal stability, air-stability, and high doping/charge injection capability, allowing for efficient organic electronic devices with reduced operating voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If low work function metals are used to improve charge carrier injection, then charge injection capability is improved, but device stability and lifetime deteriorate due to reactivity and air sensitivity
Solution Approach 1:
The patent introduces an organic compound as an intermediary layer between the electrode and the active organic material. This intermediary compound facilitates charge carrier injection while being chemically stable and air-resistant, thus resolving the contradiction between improving charge injection and maintaining device stability. The organic compound acts as a buffer that provides both electrical functionality and chemical protection.
2Use of energy by moving object
If low work function metals are used to reduce operating voltage, then operating voltage is reduced, but ease of manufacture deteriorates due to difficulty in processing and air exclusion requirements
Solution Approach 1:
The patent changes the material parameter from reactive low work function metals to organic compounds with suitable HOMO/LUMO levels. This parameter change maintains the ability to reduce operating voltage while dramatically improving ease of manufacture, as organic compounds can be processed using standard vacuum deposition or solution processing techniques without requiring rigorous air exclusion.
3Reliability
If doping is used to increase charge carrier density and conductivity, then electrical conductivity is improved, but device stability deteriorates due to use of reactive dopant materials
Solution Approach 1:
The patent employs composite material structures where stable organic compounds are combined with dopant molecules in a controlled manner. The host organic material provides chemical stability and structural integrity, while the dopant provides electrical functionality. This composite approach allows achieving high conductivity while maintaining overall device stability.
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 use of these compounds results in organic electronic devices with enhanced performance, including lower operating voltages and improved stability, overcoming the limitations of prior art devices.
Implementation Method 1
By electrically doping hole transport layers with a suitable acceptor material (p-doping) or electron transport layers with a donor material (n-doping), respectively, the density of charge carriers in organic solids (and therefore the conductivity) can be increased substantially.
Implementation Method 2
a charge transport takes place from holes or electrons to a recombination zone (light emitting layer) in the organic layer
Implementation Method 3
OLEDs are based on the principle of electroluminescence in which electron-hole pairs, so-called excitons, recombine under the emission of light
Implementation Method 4
The subsequent radiant recombination of excitons causes the emission of the visible useful light emitted by the light-emitting diode
Data Source
Figure 1~3
AI summary
The present invention relates to an organic electronic device comprising at least one substantially organic layer comprising a non fully conjugated chemical compound, and its use in organic electronic devices, specially OLEDs. The invention further comprises organic electronic comprising such compound in an electron injection layer, electron transport layers, or in a pn junction, the pn junction having at least two layers, namely a p- and n-layer, and optionally an interlayer i in between, wherein the interlayer i and/or the n-layer is (are) the substantially organic layer.