Organic Light-Emitting Element With Hole-Blocking Layer
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Solution Overview
Problem
Existing organic light emitting devices face challenges in achieving high light emission efficiency and low driving voltage.
Innovation Solution
Incorporating an organic light emitting device structure with a cathode, an anode, a light emitting layer including an anthracene derivative, and an organic material layer with a cyclic compound that acts as an electron transfer layer, providing a deep HOMO energy level and high triplet energy to enhance light emission efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional organic materials are used in the light emitting layer, then the device structure is simple, but the light emission efficiency is low and driving voltage is high
Solution Approach 1:
The patent uses a composite material system consisting of a cyclic compound (Formula 1) in the electron transfer layer and an anthracene derivative (Formula 2) in the light emitting layer. This composite approach enables high light emission efficiency (6.0 cd/A or more) and low driving voltage (3.5V or less) while maintaining device stability through the synergistic properties of the two materials.
2Ease of manufacture
If conventional organic materials are used, then material selection is easy, but device lifespan is short and thermal stability is poor
Solution Approach 1:
The patent optimizes key material parameters: the cyclic compound (Formula 1) provides a deep HOMO energy level (6.1 eV or higher) and high triplet energy (2.6 eV or higher), while the anthracene derivative (Formula 2) provides appropriate LUMO energy level (2.0-3.5 eV) and high light emission efficiency. These parameter optimizations collectively extend device lifespan to 10,000 hours or more at 85℃ and improve thermal stability.
3Reliability
If the HOMO energy level is increased to block holes, then hole blocking improves, but energy loss increases
Solution Approach 1:
The patent applies local quality by concentrating the hole blocking function specifically in the electron transfer layer using the cyclic compound (Formula 1) with deep HOMO energy level (6.1 eV or higher), while the light emitting layer (Formula 2) maintains optimal energy levels for efficient light emission. This localized functional assignment achieves effective hole blocking without compromising overall device energy efficiency.
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 proposed structure achieves high light emission efficiency, low driving voltage, and extended device lifespan by effectively blocking holes and excitons, while maintaining thermal stability.
Implementation Method 1
provides a deep HOMO energy level and high triplet energy to enhance light emission efficiency and stability
Implementation Method 2
When an organic material layer is placed between an anode and a cathode and a voltage is applied between the two electrodes, electrons and holes are injected to the organic material layer from the cathode and the anode, respectively. The electrons and the holes injected to the organic material layer are recombined to form excitons, and light emits when these excitons fall back to the ground state.
Data Source
AI summary
The present specification relates to an organic light emitting device having high light emission efficiency. Such organic light emitting device comprises a light emitting layer provided between the cathode and the anode, and including an anthracene derivative represented by the following Chemical Formula 2, and an organic material layer provide between the cathode and the light emitting layer, and including a cyclic compound represented by the following Chemical Formula 1.wherein Ar1, Ar2, X, G1, G2, m, n, R1-R8, Ar3, Ar4, L3, and I3 are described herein.