OLED Charge Generation Layer Metal Interlayer for Lower Driving Voltage
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Solution Overview
Problem
Existing organic light-emitting diodes (OLEDs) face challenges in achieving low driving voltage, high efficiency, and long lifespan due to charge accumulation at the interface of n-type and p-type charge generation layers, leading to increased driving voltage and reduced lifespan.
Innovation Solution
Incorporation of a metal interlayer with a work function of about −6.0 eV to about −3.5 eV between the n-type and p-type charge generation layers, which facilitates charge movement and minimizes charge accumulation, thereby reducing driving voltage and enhancing lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If n-type and p-type charge generation layers are directly contacted, then device structure is simple, but charge accumulation occurs at the interface leading to increased driving voltage and reduced lifespan
Solution Approach 1:
A metal interlayer with work function of -6.0 eV to -3.5 eV is introduced between the n-type and p-type charge generation layers. This metal interlayer acts as an intermediary that facilitates charge movement and prevents charge accumulation at the interface, thereby extending OLED lifespan without significantly increasing structural complexity
Solution Approach 2:
The patent changes the work function parameter of the charge generation layer interface by introducing a metal interlayer with specific work function range (-6.0 eV to -3.5 eV). This parameter change enables effective charge transfer and prevents charge accumulation, resolving the contradiction between reliability and device complexity
2Power
If charge accumulation is suppressed by optimizing charge generation layer structure, then driving voltage is reduced, but device structure becomes more complex
Solution Approach 1:
The metal interlayer serves as a mediator that enables efficient charge transfer between n-type and p-type charge generation layers. This intermediary structure reduces charge accumulation and lowers driving voltage while adding minimal structural complexity compared to complete redesign of the charge generation layer system
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 metal interlayer effectively suppresses charge accumulation, resulting in lower driving voltage and improved OLED lifespan while maintaining efficiency.
Implementation Method 1
the metal interlayer includes metal having a work function of about −6.0 eV to about −3.5 eV
Data Source
AI summary
A display apparatus including a pixel electrode disposed on a substrate, an opposite electrode disposed to face the pixel electrode, a first emission layer and a second emission layer disposed on the first emission layer and overlapping each other between the pixel electrode and the opposite electrode, and a charge generation layer disposed between the first emission layer and the second emission layer, in which the charge generation layer includes an n-type charge generation layer, a p-type charge generation layer, and a metal interlayer disposed between the n-type charge generation layer and the p-type charge generation layer, and the metal interlayer includes metal having a work function of about −6.0 eV to about −3.5 eV.