Organic EL Emitting Layer Materials for Low-Voltage Efficiency
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Solution Overview
Problem
Current organic electroluminescence (EL) devices face challenges in achieving high emission efficiency and long lifetime, particularly with existing compounds used in these devices.
Innovation Solution
A compound with a specific substituent introduced into a dibenzofluorene skeleton containing a spiro atom is used as a material for organic EL devices, enhancing carrier mobility and functionality as a host or dopant in light emitting layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional compounds are used in organic EL devices, then device structure can be maintained, but emission efficiency is insufficient and lifetime is short
Solution Approach 1:
The patent modifies the molecular structure parameters of the host material by introducing specific substituents (naphthalene or phenanthrene rings with various functional groups) at designated positions on the dibenzofluorene skeleton. This structural parameter change optimizes carrier mobility and excited state properties, simultaneously improving both emission efficiency and device lifetime without requiring fundamental changes to the device architecture.
Solution Approach 2:
The invention creates a composite molecular structure by combining the dibenzofluorene core with naphthalene or phenanthrene ring systems and various functional substituents. This composite approach integrates multiple beneficial properties: the spiro structure provides rigidity and prevents aggregation, while the introduced rings and substituents enhance carrier transport and light emission properties, achieving both high efficiency and long lifetime.
2Productivity
If doping concentration is increased to improve emission efficiency, then more light is emitted, but device complexity and material optimization difficulty increase
Solution Approach 1:
The patent optimizes the host material's intrinsic properties through structural modification rather than relying solely on doping concentration adjustments. By changing molecular parameters (ring systems, substituents), the material achieves better carrier mobility and excited state stability, allowing high emission efficiency at optimized but not excessive doping levels, thus simplifying the overall material system design.
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 organic EL device exhibits high emission efficiency at low voltage and prolonged lifetime, effectively addressing the limitations of previous compounds by utilizing the new material in light emitting layers.
Implementation Method 1
the compound of the invention for use as a material for organic EL devices has a high carrier mobility
Implementation Method 2
When a voltage is applied between the electrodes, electrons are injected from the cathode and holes are injected from the anode into a light emitting region. The injected electrons recombine with the injected holes in the light emitting region to form excited states. When the excited states return to the ground state, the energy is released as light.
Data Source
AI summary
The compound represented by formula (1):wherein A, B, R1, and R2 are as defined in the description,provides organic electroluminescence (EL) devices having a high emission efficiency when operated at low voltage and a long lifetime and electronic devices including such organic EL devices.