Condensed Cyclic Compound for OLED Thermal Stability

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Solution Overview

Problem

Existing organic light-emitting devices face challenges in achieving high durability and electrical stability due to limitations in glass transition temperature and charge transport ability, which affect their performance and lifespan.

Innovation Solution

A condensed cyclic compound represented by Formula 1 is integrated into the light-emitting device, featuring a structure with a central cyclic group condensed with three cyclic groups, enhancing the glass transition temperature and allowing for improved electrical stability and charge transport, thereby increasing the device's durability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional organic light-emitting devices are used, then device structure is simple, but glass transition temperature is low and electrical stability is insufficient

Engineering Contradiction:

Improveglass transition temperatureVSAvoidcompound structure complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The patent modifies the molecular structure parameters of organic compounds by introducing condensed cyclic groups (such as dibenzofuran, dibenzothiophene, carbazole) to increase the glass transition temperature from typical values below 100°C to above 150°C, thereby improving electrical stability without fundamentally changing the device architecture

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite molecular structures combining electron-donating groups (carbazole, dibenzofuran) with electron-accepting groups (dibenzothiophene, triphenylene) to create compounds with both high glass transition temperature and excellent charge transport properties, resolving the contradiction between thermal stability and electrical performance

Inventive Principle:

Principle #40Composite materials

2Reliability

If conventional organic compounds are used in emission layers, then charge transport ability is limited, but device manufacturing is easier

Engineering Contradiction:

Improveelectrical stabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent introduces specific functional groups at localized positions within the molecular structure (such as carbazole groups for hole transport, dibenzothiophene for electron transport) to enhance charge transport ability in specific regions while maintaining overall molecular stability and ease of fabrication

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent optimizes molecular weight, glass transition temperature, and HOMO-LUMO energy levels of organic compounds to achieve balanced charge transport properties, enabling reliable device operation while maintaining compatibility with conventional vacuum deposition and solution processing manufacturing methods

Inventive Principle:

Principle #35Parameter changes

3Duration of action of stationary object

If existing organic light-emitting devices are used, then device lifespan is limited, but driving voltage is currently acceptable

Engineering Contradiction:

Improvedevice lifespanVSAvoiddriving voltage

Core Design Contradiction:

Duration of action of stationary objectVSUse of energy by moving object

Solution Approach 1:

The patent adjusts the glass transition temperature parameter of organic compounds to above 150°C and optimizes molecular structure for enhanced thermal and electrical stability, which extends device lifespan by preventing material degradation while maintaining driving voltage within acceptable ranges through balanced charge transport properties

Inventive Principle:

Principle #35Parameter changes

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 the condensed cyclic compound results in a light-emitting device with increased resistance to high temperatures, improved electrical stability, and extended lifespan, along with reduced driving voltage and enhanced luminance efficiency.

Implementation Method 1

enhancing the glass transition temperature

Methodology Applied

Scientific EffectGlass transition:

Implementation Method 2

allowing for improved electrical stability and charge transport

Methodology Applied

Scientific EffectCharge transport: Conduction (electrical)

Implementation Method 3

Carriers (such as holes and electrons) may recombine in the emission layer to produce excitons. These excitons may transition from an excited state to the ground state, thereby generating light.

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS20230051889A1Condensed cyclic compound, light-emitting device including the same, and electronic apparatus including the light-emitting device

Publication Date: 2023.02.16 SAMSUNG DISPLAY CO LTD

AI summary

A light-emitting device and an electronic apparatus including the light-emitting device include a novel condensed cyclic compound represented by Formula 1, in which Z1 is a group represented by Formula 2. The condensed cyclic compound represented by Formula 1 may have a high glass transition temperature (Tg) and/or a high melting point, and may thus provide high durability during storage and driving.