Silicon-Substituted Organic Compound for OLED Luminance and Efficiency
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Solution Overview
Problem
Current organic electroluminescence devices face challenges in achieving high luminance, luminous efficiency, and durability, particularly in blue phosphorescent devices, due to low excitation triplet energy and quenching of light emission, as well as insufficient charge injecting and transporting performance.
Innovation Solution
Incorporating a compound with a silicon substituent in the organic layer, specifically a light-emitting layer, to enhance luminance and efficiency, and using a platinum complex or iridium complex with a tridentate or tetradentate ligand to improve phosphorescent material performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If materials having a triphenylsilyl group are used as host materials, then aptitude for vacuum deposition and amorphous property are improved, but T1 energy becomes low and quenching of phosphorescent emission occurs
Solution Approach 1:
The patent changes the chemical structure parameters of the host material by introducing a carbazole core with specific substituents (triphenylsilyl group combined with other electron-withdrawing or electron-donating groups) to achieve both high T1 energy and good vacuum deposition properties. This structural parameter optimization allows the material to maintain amorphous film formation while avoiding quenching of phosphorescent emission.
2Ease of manufacture
If materials having a triphenylsilyl group are used as host materials, then aptitude for vacuum deposition and amorphous property are improved, but charge injecting and transporting performances become low and driving voltage increases
Solution Approach 1:
The patent creates a composite molecular structure combining carbazole (known for good charge transport) with triphenylsilyl groups (known for vacuum deposition aptitude). This composite structure integrates the advantages of both components: the carbazole core provides excellent charge injecting and transporting properties, while the triphenylsilyl substituents ensure good vacuum deposition and amorphous film formation, thereby reducing driving voltage.
3Ease of manufacture
If compounds with aromatic heterocyclic ring and trimethylsilyl group substituted on ortho-position are used, then device structure is formed, but durability is insufficient
Solution Approach 1:
The patent optimizes the molecular structure by selecting specific substituent groups (beyond simple trimethylsilyl) and their positions on the carbazole and aromatic heterocyclic rings. This structural parameter refinement enhances the chemical and thermal stability of the host material, thereby improving device durability while maintaining the ability to form the required device structure through vacuum deposition.
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 electroluminescence device exhibits improved luminance, luminous efficiency, and durability, particularly in the blue region, with enhanced charge transporting properties and reduced driving voltage, utilizing the silicon substituent and platinum or iridium complexes.
Implementation Method 1
organic electroluminescence devices are capable of obtaining emission of light of high luminance by low voltage driving... electrons injected from the cathode and holes injected from the anode are recombined in the organic layer, and generated energy of exciton is used for emission of light
Implementation Method 2
increment in efficiency of devices has been advanced by the use of phosphorescent materials... As the phosphorescent materials, inventions in connection with phosphorescent devices using iridium complexes and platinum complexes
Data Source
AI summary
An organic electroluminescence device includes an anode; a cathode; and at least one organic layer, wherein the at least one organic layer includes a first organic layer which is a light-emitting layer being provided between the anode and the cathode and containing at least one light-emitting material, and the at least one organic layer contains at least one compound represented by formula (I):wherein Q1 represents an aromatic heterocyclic ring; each of R1, R2, R3 and R4 independently represents a hydrogen atom or a substituent; and each of R11, R12 and R13 independently represents an alkyl group, an aryl group, or an aromatic heterocyclic group, provided that at least one of R11, R12 and R13 represents an aryl group or an aromatic heterocyclic group.