Bipolar Organic Compound for OLED Efficiency and Lifetime
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Solution Overview
Problem
Conventional organic light emitting diodes (OLEDs) face limitations in luminous efficiency due to the low participation of triplet excitons in the luminous process, and phosphorescent materials with high efficiency have short luminous lifetimes, limiting their commercial applications.
Innovation Solution
An organic compound with a high excited triplet energy level and bipolar properties is introduced, featuring a pyridine moiety for electron affinity and fused aromatic or heteroaromatic groups for hole affinity, which is incorporated into the emissive layer to enhance luminous efficiency and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phosphorescent material is used to increase luminous efficiency, then triplet excitons participate in luminous process, but luminous lifetime becomes short
Solution Approach 1:
The patent changes the energy level parameters of the host material by selecting specific compounds with high triplet energy levels (Et > 2.1 eV). This parameter change allows the system to maintain high luminous efficiency while extending luminous lifetime, as the high Et prevents triplet exciton quenching and enables both singlet and triplet excitons to contribute to luminescence without the short lifetime limitation of conventional phosphorescent materials.
2Productivity
If common fluorescent material is used, then only singlet excitons participate in luminous process, but luminous efficiency remains low
Solution Approach 1:
The patent converts the previously harmful or wasted triplet excitons into beneficial light-emitting species. By using a host material with high triplet energy level, the triplet excitons that would normally be lost are now retained and can participate in the luminous process, transforming energy loss into useful luminescence and achieving high luminous efficiency.
3Stability of the object's composition
If material with high triplet energy level is selected, then thermal stability is improved, but device complexity increases
Solution Approach 1:
The patent employs composite material design by combining specific host materials with high triplet energy levels and appropriate dopants. This composite approach achieves the desired thermal stability and luminous properties while managing material selection complexity through systematic pairing of host-guest systems with complementary characteristics.
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 compound improves luminous efficiency, extends the luminous lifetime, and reduces driving voltage and power consumption by facilitating balanced charge injection and recombination, while maintaining thermal stability and high triplet energy levels.
Implementation Method 1
when electrical charges are injected into an emitting material layer between an electron injection electrode (i.e., cathode) and a hole injection electrode (i.e., anode), electrical charges are recombined to form excitons, and then emit light as the recombined excitons are shifted to a stable ground state
Implementation Method 2
An organic compound having high excited triplet energy level and bipolar property, and having enhanced affinity to charges
Data Source
AI summary
The present disclosure relates to an organic compound having improved luminescent properties, an organic light emitting diode and organic light emitting device including the organic compound, the organic compound having the following structure. The organic compound is a bipolar compound having both a p-type moiety and an n-type moiety and has high energy level, large energy bandgap and improved thermal stability. Applying the organic compound into an emissive layer of the OLED allows holes and electrons to be recombined at whole area of an emitting material layer, and thereby enhancing the luminous efficiency and the luminous lifetime of the OLED.