Blue OLED Emitting Layer Structure for Efficiency and Lifespan
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Solution Overview
Problem
The OLED in the blue pixel does not provide sufficient emitting efficiency and lifespan, limiting the performance of organic light emitting display devices.
Innovation Solution
The OLED includes a first and second blue emitting layer with specific anthracene derivative hosts and dopants, along with an electron transporting layer, to enhance efficiency and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional emitting materials are used in blue OLEDs, then device complexity is reduced, but emitting efficiency and lifespan are insufficient
Solution Approach 1:
The emitting layer is divided into multiple distinct layers (first emitting layer, second emitting layer, third emitting layer) with different functions. The first emitting layer handles hole injection and transport, the second emitting layer is the primary light emission zone, and the third emitting layer handles electron injection and transport. This segmentation allows each layer to be optimized for its specific function, improving overall device reliability and lifespan while managing complexity through functional specialization.
Solution Approach 2:
The patent employs composite material structures within each emitting layer, combining multiple organic compounds with specific properties. Each layer uses a combination of host materials, dopants, and functional materials with tailored molecular structures and energy levels. This composite approach enables optimization of charge transport, exciton management, and light emission properties to achieve superior emitting efficiency and device stability.
2Productivity
If conventional emitting materials are used in blue OLEDs, then manufacturing process is simplified, but emitting efficiency is insufficient
Solution Approach 1:
Each emitting layer is designed with specific local qualities tailored to its function. The first emitting layer uses materials optimized for hole injection and transport properties, the second emitting layer uses materials optimized for light emission efficiency and exciton management, and the third emitting layer uses materials optimized for electron injection and transport. This local optimization of material properties in each zone achieves high emitting efficiency while maintaining a systematic fabrication approach.
Solution Approach 2:
The patent systematically varies key parameters across different emitting layers, including HOMO/LUMO energy levels, charge mobility, exciton binding energy, and material composition ratios. By carefully controlling these parameters in each layer and at their interfaces, the device achieves optimal charge injection, transport, and recombination processes that maximize emitting efficiency while using established organic material synthesis and deposition techniques.
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 improves the driving voltage, emitting efficiency, and lifespan of the OLED, particularly in blue pixel regions.
Implementation Method 1
The OLED emits light by injecting electrons from a cathode as an electron injection electrode and holes from an anode as a hole injection electrode into an emitting material layer (EML), combining the electrons with the holes, generating an exciton, and transforming the exciton from an excited state to a ground state
Data Source
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AI summary
The present invention relates to an organic light emitting diode comprising a first electrode (160); a second electrode (164) facing the first electrode; and a first emitting part (162) including a first blue emitting layer (250), a second blue emitting layer (260), an electron transporting layer (280) and positioned between the first and second electrode, wherein the first blue emitting layer includes a first host (252) and a first dopant (254), and the second blue emitting layer includes a second host (262) and a second dopant (264), wherein the first host is an anthracene derivative having a first deuteration ratio, and the second host is an anthracene derivative having a second deuteration ratio smaller than the first deuteration ratio, wherein the first dopant is a first compound represented by Formula 3, and wherein the first electron transporting layer includes an electron transporting material represented by Formula 9.