OLED Transport and Blocking Layers for Exciton Confinement
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Solution Overview
Problem
Current organic light emitting diodes (OLEDs) face challenges in achieving high light emitting efficiency due to limitations in materials used for electron transport and blocking layers, which affect the stability and confinement of excitons, leading to inefficient light emission.
Innovation Solution
Incorporating a compound represented by Chemical Formula 1 as an electron transport layer and another compound represented by Chemical Formula 2 as an electron blocking layer in the OLED structure, both of which exhibit bipolar properties, allowing for effective confinement of excitons and enhanced light emitting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional organic materials are used for electron transport and blocking layers, then the device structure is simple, but light emitting efficiency is low due to poor exciton confinement and stability
Solution Approach 1:
The patent employs composite material structures where the electron transport layer combines compounds of Formula 1 (with specific heterocyclic structures containing N atoms) and the electron blocking layer uses compounds of Formula 2 (spirobifluorene-monoamine-based). These composite material designs with specific molecular structures achieve superior exciton confinement and stability, resolving the contradiction between improved light emitting efficiency and material structure complexity.
2Duration of action of stationary object
If conventional electron transport materials are used, then the device is easier to manufacture, but exciton stability is poor leading to reduced lifespan
Solution Approach 1:
The patent changes the chemical and physical parameters of the electron transport and blocking layer materials by using specifically designed compounds (Formula 1 with heterocyclic N-containing structures and Formula 2 spirobifluorene-monoamine compounds). These parameter changes in material composition and molecular structure improve exciton stability and device lifespan, while the compounds are designed to be compatible with conventional manufacturing processes.
3Productivity
If conventional materials are used for electron blocking layer, then the overall device complexity is reduced, but hole leakage occurs reducing light emitting efficiency
Solution Approach 1:
The patent applies local quality by designing the electron blocking layer with specific compounds (Formula 2) that have tailored properties for preventing hole leakage at the interface with the light emitting layer. The spirobifluorene-monoamine-based compounds provide localized functional properties exactly where needed (at the electron blocking layer), improving light emitting efficiency without requiring complex changes throughout the entire device structure.
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
This configuration results in an OLED with improved light emitting efficiency, reduced driving voltage, and extended lifespan by preventing hole leakage and maintaining exciton stability, outperforming existing materials in these aspects.
Implementation Method 1
An organic light emission phenomenon is an example of converting current into visible rays by an internal process of a specific organic molecule. When an organic material layer is positioned between an anode and a cathode, if a voltage is applied between two electrodes, electrons and holes are respectively injected from the cathode and the anode into the organic material layer. The electrons and the holes which are injected into the organic material layer are recombined to form excitons, and light is emitted while the excitons fall down to a bottom state again.
Data Source
AI summary
Provided is an organic light emitting device having between the cathode and a light emitting layer an an organic material layer containing a compound of any one of the following Chemical Formulae 1-2 to 1-4:wherein:X1 to X3 are each independently N or CH, and at least one of X1 to X3 is N;L1 is a substituted or unsubstituted monocyclic arylene group having 6 to 24 carbon atoms;Ar1 and Ar2 are the same as or different from each other, and are each independently a substituted or unsubstituted monocyclic or polycyclic aryl group having 6 to 20 carbon atoms; andZ1 is deuterium;and an organic material layer provided between the anode and the light emitting layer and including a spirobifluorene-monoamine based compound of Chemical Formula 2: