Multi-Emission OLED Transport Stack for Lower Operating Voltage
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Solution Overview
Problem
Existing multi-emission-layer organic light-emitting diodes (OLEDs) face challenges in efficiency and voltage performance, particularly in top emission configurations.
Innovation Solution
Incorporating a specific electron transport layer stack comprising compounds of Formula (I) and (II) between emission layers, with tailored molecular structures and dipole moments, and excluding electrical dopants, to enhance electron transport and balance charge injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional electron transport materials are used in multi-emission-layer OLEDs, then device structure can be maintained, but efficiency and voltage performance are insufficient
Solution Approach 1:
The patent changes the molecular parameters of electron transport materials by introducing specific dipole moments and molecular structures (Formulas I and II) to optimize electron transport properties. This parameter optimization directly improves device efficiency and reduces energy loss without requiring structural changes to the OLED architecture.
Solution Approach 2:
The patent employs composite electron transport layer designs combining multiple materials with complementary properties. The electron transport layer stack integrates compounds of Formula (I) and Formula (II) with different dipole moments and transport characteristics, creating a synergistic composite structure that enhances overall device efficiency while minimizing energy losses.
2Ease of operation
If conventional electron transport layers are used, then manufacturing process remains simple, but operating voltage is too high
Solution Approach 1:
The patent optimizes the dipole moment parameters of electron transport materials to match energy levels between layers. By carefully selecting compounds with specific dipole moments (as shown in Formulas I and II), the patent reduces energy barriers for electron transport, thereby lowering operating voltage and subsequent power consumption while maintaining ease of device operation.
3Productivity
If charge injection balance is not optimized, then device structure remains simple, but efficiency is poor
Solution Approach 1:
The patent applies local quality optimization by designing electron transport layers with specific regional characteristics. The electron transport layer stack incorporates compounds with tailored dipole moments and molecular structures at different positions (Formulas I and II) to create optimal local conditions for charge injection balance, improving efficiency without requiring complex overall device architecture.
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
Improves efficiency and reduces operating voltage in OLED devices, particularly in display and lighting applications.
Implementation Method 1
Incorporating a specific electron transport layer stack comprising compounds of Formula (I) and (II) between emission layers, with tailored molecular structures and dipole moments
Implementation Method 2
The holes and electrons recombine in the EML to generate excitons. When the excitons drop from an excited state to a ground state, light is emitted.
Data Source
Figure 1
Figure 2A~2C
AI summary
The present invention relates to an organic light emitting diode comprising an anode, a cathode, a first emission layer, a second emission layer, a first charge generation layer and a first electron transport layer stack; and to a display device or lighting device comprising the same.