Carbazole Condensed Cyclic Compounds for Deep Blue OLEDs

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Solution Overview

Problem

Current organic light-emitting devices (OLEDs) face challenges in achieving low driving voltage, high efficiency, high brightness, and long lifespan while maintaining high color purity and deep blue light emission.

Innovation Solution

The development of novel condensed cyclic compounds, represented by Formula 1, which are integrated into the organic layer of OLEDs, enabling high triplet energy levels and thermally activated delayed fluorescence (TADF) emission, thereby enhancing the device's efficiency and lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional organic compounds are used in OLEDs, then device structure is simple, but driving voltage is high and efficiency is low

Engineering Contradiction:

Improvedriving voltageVSAvoidcompound structure

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The patent modifies molecular parameters by introducing specific heteroatoms (N, O, S) and functional groups (carbazole, dibenzofuran, dibenzothiophene) to optimize HOMO/LUMO energy levels and triplet energy, thereby reducing driving voltage and improving efficiency

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite molecular structures combining multiple heterocyclic rings and functional groups in defined configurations (Formula 1) to achieve synergistic effects that simultaneously improve electrical properties, emission characteristics, and device performance

Inventive Principle:

Principle #40Composite materials

2Productivity

If conventional organic compounds are used in OLEDs, then manufacturing is simple, but luminous efficiency and quantum efficiency are low

Engineering Contradiction:

Improveluminous efficiencyVSAvoidsynthesis complexity

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent optimizes molecular parameters including triplet energy levels (T1 > 2.1 eV) and HOMO/LUMO gaps to enhance luminous efficiency and quantum efficiency through improved charge carrier transport and recombination mechanisms

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent divides the molecular structure into distinct functional segments (core heterocyclic rings, linking groups, terminal substituents) that can be independently optimized and assembled through modular synthesis approaches

Inventive Principle:

Principle #1Segmentation

3Duration of action of stationary object

If conventional organic compounds are used in OLEDs, then device operation is simple, but lifespan is short

Engineering Contradiction:

Improvedevice lifespanVSAvoidmolecular design

Core Design Contradiction:

Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The patent adjusts molecular parameters such as triplet energy levels and molecular weight to improve operational stability and lifespan by reducing degradation mechanisms while maintaining emission performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent designs molecules with inherent stability features that prevent degradation without requiring complex protective structures, effectively creating self-protecting materials

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Illumination intensity

If conventional organic compounds are used in OLEDs, then color emission is achieved, but color purity and deep blue emission are insufficient

Engineering Contradiction:

Improvecolor purityVSAvoidmolecular structure

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The patent precisely controls molecular parameters including HOMO-LUMO gap and triplet energy level to tune emission wavelength into the deep blue region (450-480 nm) with high color purity by optimizing orbital energy differences

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces specific local functional groups and heteroatom arrangements within the molecular structure to create localized electronic states that emit at specific wavelengths with narrow bandwidths for high color purity

Inventive Principle:

Principle #3Local quality

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 use of these compounds results in OLEDs with low driving voltage, high luminance, high quantum efficiency, and extended lifespan, while achieving deep blue light emission with high color purity.

Implementation Method 1

enabling high triplet energy levels and thermally activated delayed fluorescence (TADF) emission

Methodology Applied

Scientific EffectThermally activated delayed fluorescence (TADF):

Implementation Method 2

Carriers, such as holes and electrons, are recombined in the emission layer to produce excitons. These excitons change from an excited state to a ground state, thereby generating light.

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3109247B1Carbazole compound or analogues thereof and organic light-emitting device including the same

Publication Date: 2020.04.22 SAMSUNG ELECTRONICS CO LTD

Figure 1

AI summary

A condensed cyclic compound represented by Formula 1: wherein, in Formula 1, groups and variables are the same as described in the specification.