Pyrene Compound Substitution for OLED Blue Purity

Solution Overview

Problem

Existing organic electroluminescent elements using pyrene compounds struggle with achieving high blue color purity and luminous efficiency, particularly when substituents are placed on the long axis of the pyrene ring, and exhibit poor performance when used as light emitting materials.

Innovation Solution

The development of organic electroluminescent elements incorporating pyrene compounds with specific substituents on the short axis of the pyrene ring, where electron-donating groups are present, and the absence of such groups on the long axis, along with the use of anthracene-based host materials, to enhance chromaticity and luminous efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If pyrene compounds with substituents on the long axis (positions 1, 2, 3, 6, 7, 8) are used, then blue color purity is improved, but luminous efficiency deteriorates

Engineering Contradiction:

Improveblue color purityVSAvoidluminous efficiency

Core Design Contradiction:

Illumination intensityVSLoss of energy

Solution Approach 1:

The patent applies local quality by placing electron-donating substituents specifically at positions 4 and 9 (short axis) of the pyrene ring, while keeping positions 1, 2, 3, 6, 7, 8 (long axis) unsubstituted or with electron-withdrawing groups. This localized substitution strategy optimizes both color purity and luminous efficiency by assigning different functional roles to different regions of the molecule.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces asymmetry by using non-equivalent substitution patterns on the pyrene ring. Specifically, it places substituents at positions 4 and 9 which are asymmetrically positioned relative to the long axis, creating an asymmetric electron distribution that improves both chromaticity and efficiency simultaneously.

Inventive Principle:

Principle #4Asymmetry

2Illumination intensity

If pyrene compounds with electron-donating groups on the long axis are used, then chromaticity is improved, but power consumption increases

Engineering Contradiction:

ImprovechromaticityVSAvoidpower consumption

Core Design Contradiction:

Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by placing electron-donating substituents specifically at positions 4 and 9 (short axis) of the pyrene ring, while keeping positions 1, 2, 3, 6, 7, 8 (long axis) unsubstituted or with electron-withdrawing groups. This localized substitution strategy optimizes both color purity and luminous efficiency by assigning different functional roles to different regions of the molecule.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the electronic parameters of the pyrene compound by selecting substituents with specific electron-donating capabilities and placing them at optimized positions. This parameter optimization allows achieving high chromaticity with reduced power consumption by fine-tuning the HOMO-LUMO gap and charge transport properties.

Inventive Principle:

Principle #35Parameter changes

3Loss of energy

If pyrene compounds with substituents at positions 4 and 9 are used, then luminous efficiency is improved, but blue color purity deteriorates

Engineering Contradiction:

Improveluminous efficiencyVSAvoidblue color purity

Core Design Contradiction:

Loss of energyVSIllumination intensity

Solution Approach 1:

The patent introduces asymmetry by using non-equivalent substitution patterns on the pyrene ring. Specifically, it places substituents at positions 4 and 9 which are asymmetrically positioned relative to the long axis, creating an asymmetric electron distribution that improves both chromaticity and efficiency simultaneously.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent creates a composite molecular structure by combining the pyrene core with specific substituents (such as carbazole, triphen胺, or their derivatives) at positions 4 and 9. This composite structure integrates the advantages of both the pyrene framework (for efficiency) and the substituent groups (for color tuning), achieving high luminous efficiency and blue color purity simultaneously.

Inventive Principle:

Principle #40Composite materials

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 proposed solution results in organic electroluminescent elements with improved luminous efficiency, excellent chromaticity, and reduced power consumption, specifically achieving high blue color purity and stability.

Implementation Method 1

utilize, for light emitting, energy of the exciton generated as a result of recombination of the electron injected from the cathode and the hole injected from the anode in the organic layer

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS11563178B2Organic electroluminescent element, compound for use in the element, and light emitting device, display device, and illumination device using the element

Publication Date: 2023.01.24 UDC IRELAND

AI summary

The disclosure relates to organic electroluminescent elements, compounds for use in the elements, and devices using the elements, which include a compound represented by the following General Formula (1):where R1 to R3 and R6 to R8 each independently represents a hydrogen atom, which may be a deuterium atom, or a substituent with a Hammett substituent constant σp value of −0.15 or more, R5, R9 and R10 each independently represents a hydrogen atom or a substituent, L1 represents a divalent linking group, DG1 represents a donor group, and n1 represents 1 or 2, and where R1 to R3, R5 to R10, L1, and DG1 are not bound to each other to form a ring.