Circularly polarized light-emitting material and use, light-emitting display device, and display apparatus
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Solution Overview
Problem
Existing cyclometalated platinum (II) and palladium (II) complexes for circularly polarized luminescence suffer from low chemical and thermal stability, racemization issues, and difficulty in achieving optically pure enantiomers, limiting their application in stable and efficient OLED devices.
Innovation Solution
A central chiral-induced helical-chiral tetradentate cyclometalated platinum (II) and palladium (II) complex is developed, utilizing a central chiral segment in the tetradentate ligand to form an optically pure helical-chiral metal complex with high chemical and thermal stability, without the need for chiral resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bidentate cyclometalated platinum (II) and palladium (II) complexes are used, then the molecular structure is flexible and easy to synthesize, but the luminescence quantum efficiency decreases due to easy distortion and vibration of ligands
Solution Approach 1:
The patent applies local quality by introducing a rigidified bidentate ligand system with specific structural features (aromatic rings, conjugated bonds) at key positions to locally enhance molecular rigidity and suppress non-radiative decay, while maintaining the overall flexibility and synthesizability of the bidentate complex framework
2Loss of energy
If tridentate ligand-based cyclometalated platinum (II) and palladium (II) complexes are used, then the luminescence quantum efficiency improves due to enhanced molecular rigidity, but the chemical stability and thermal stability decrease due to second monodentate ligands
Solution Approach 1:
The patent extracts and removes the problematic second monodentate ligands (such as Cl−, phenoxy anion, alkyne anion, carbene) that cause decreased chemical and thermal stability, while retaining the rigidified bidentate ligand system that provides enhanced luminescence quantum efficiency through molecular rigidity
Solution Approach 2:
The patent creates a composite ligand system combining rigidified bidentate ligands with appropriate counter ligands to achieve both high luminescence quantum efficiency and improved chemical/thermal stability, forming a synergistic complex structure that overcomes the limitations of individual ligand types
3Loss of energy
If tetradentate ligand-based cyclometalated platinum (II) and palladium (II) complexes are used, then the molecular rigidity increases and nonradiative relaxation is suppressed, but the material molecules present distorted quadrilateral configuration that is easily racemized in solution or during heating sublimation
Solution Approach 1:
The patent introduces asymmetric structural features and chiral centers into the tetradentate ligand system to create helical-chiral configurations that are resistant to racemization, while maintaining the high molecular rigidity needed to suppress nonradiative relaxation
Solution Approach 2:
The patent employs curved or helical structural motifs in the tetradentate ligand arrangement to create three-dimensional chiral configurations that enhance both rigidity and resistance to racemization, transforming the planar distorted quadrilateral into a stable three-dimensional chiral structure
4Ease of manufacture
If conventional cyclometalated complexes are used, then the synthesis process is straightforward, but chiral resolution is required to obtain optically pure enantiomers, increasing preparation complexity and cost
Solution Approach 1:
The patent incorporates chiral centers and helical-chiral configurations into the ligand structure during the synthesis process itself, so that the complex is formed directly as the desired optically active enantiomer without requiring subsequent chiral resolution steps, thereby simplifying the overall preparation process
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 solution provides optically pure, stable, and efficient circularly polarized light-emitting materials suitable for OLED devices, reducing preparation costs and maintaining luminescence properties under various conditions.
Implementation Method 1
Circularly polarized luminescence (CPL) is a phenomenon in which levorotatory or dextrorotatory circularly polarized light is emitted from a chiral light-emitting material upon excitation
Implementation Method 2
Cyclometalated platinum (II) and palladium (II) complexes phosphorescent materials can make full use of all singlet and triplet excitons generated by electroexcitation due to their heavy atom effect
Implementation Method 3
The central metal ions of divalent cyclometalated platinum (II) and palladium (II) complexes are both dsp2 hybridized and easily coordinate with tetradentate ligands to form stable and rigid planar quadrilateral molecules
Implementation Method 4
Cyclometalated platinum (II) and palladium (II) complexes phosphorescent materials can make full use of all singlet and triplet excitons generated by electroexcitation
Data Source
AI summary
Disclosed in the present invention are a helical-chiral tetradentate cyclometalated platinum (II) and palladium (II) complex circularly polarized light-emitting material based on phenyl-benzimidazole and a derivative thereof, and a use. The helical-chiral metal complex molecule can, by means of a central chiral segment La in a tetradentate ligand, autonomously induce the whole tetradentate ligand to coordinate with metal ions in a small steric hindrance manner to form an optically pure helical-chiral metal complex circularly polarized light-emitting material. The helical-chiral metal complex circularly polarized light-emitting material does not require chiral resolution, has high chemical stability and thermal stability, and has important applications in circularly polarized light-emitting elements.