Low Refractive Index Organic Compound for OLED Outcoupling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic light-emitting devices (OLEDs) face challenges with low outcoupling efficiency due to refractive index differences between layers, which affects device efficiency and reliability, as a low refractive index is difficult to achieve without compromising carrier-transport properties.
Innovation Solution
Development of organic compounds with a specific molecular structure, such as those represented by General Formula (G1), (G2), and (G3), which incorporate pyrimidine, pyrazine, or triazine skeletons with a high proportion of sp3 hybridized carbon atoms, balancing low refractive index with high electron-transport properties and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a low refractive index material is used in the EL layer, then outcoupling efficiency is improved, but carrier-transport property deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the organic compound by introducing sp3-hybridized carbon atoms into the molecular structure. This parameter change reduces the refractive index from conventional values (typically 1.7-1.9) to below 1.7, thereby improving outcoupling efficiency while maintaining adequate carrier-transport properties through careful molecular design
Solution Approach 2:
The patent creates a composite molecular structure combining sp2-hybridized aromatic rings (for carrier transport) with sp3-hybridized carbon atoms (for reducing refractive index). This composite approach at the molecular level allows simultaneous optimization of optical properties and electrical properties that were previously traded off against each other
2Loss of energy
If a low refractive index material is used in the EL layer, then device efficiency is improved, but reliability deteriorates
Solution Approach 1:
The patent modifies molecular parameters by incorporating sp3-hybridized carbon atoms in specific proportions (1-60% of total carbon atoms) into the organic compound structure. This controlled parameter change achieves lower refractive index for improved efficiency while maintaining thermal stability and device reliability through appropriate molecular design
Solution Approach 2:
The patent applies local quality by introducing sp3-hybridized carbon atoms at specific positions within the molecular structure rather than uniformly throughout. This localized modification allows reduction of refractive index in specific regions while preserving carrier-transport pathways and maintaining overall device reliability
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
These compounds enhance outcoupling efficiency and emission efficiency while maintaining high reliability and low power consumption in OLEDs, offering a trade-off between refractive index and carrier-transport properties.
Implementation Method 1
Light-emitting devices (organic EL devices) including organic compounds and utilizing electroluminescence (EL) have been put to more practical use. Carriers are injected by application of voltage to the device, and recombination energy of the carriers is used, whereby light emission can be obtained from the light-emitting material.
Implementation Method 2
Low outcoupling efficiency is often a problem in an organic EL device. In particular, the attenuation due to reflection which is caused by a difference in refractive index between adjacent layers is a main cause of a reduction in device efficiency.
Data Source
AI summary
An electron-transport layer material with a low refractive index is provided. An organic compound represented by General Formula (G1) is provided. In General Formula (G1), one to three of Q1 to Q3 represent N and when one or two of Q1 to Q3 represent N, the remaining two or one of Q1 to Q3 represent CH. Furthermore, R0 represents any of hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, and a group represented by Formula (G1-1). At least one of R1 to R15 represents a substituted or unsubstituted group including any one of a pyrimidinyl group, a pyrazinyl group, and a triazinyl group, and the others each independently represent any of hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 14 carbon atoms forming a ring, and a substituted or unsubstituted pyridinyl group.