Pyrene-Triphenylamine Condensed-Cyclic Compound for OLED Emission Layer

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Solution Overview

Problem

Current organic light-emitting diodes (OLEDs) face challenges in achieving low driving voltage, high brightness, and long lifespan while maintaining high quantum efficiency due to limitations in the materials used in their emission layers.

Innovation Solution

Incorporating a condensed-cyclic compound represented by Formula 1, which includes a π-conjugation system formed by the fusion of pyrene and pyridine, into the OLED structure, specifically in the emission layer, to reduce non-radiative decay and enhance light-emitting efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional organic compounds are used in the emission layer, then the OLED structure is simple, but the quantum efficiency and light-emitting efficiency are limited

Engineering Contradiction:

Improvequantum efficiencyVSAvoidcompound structure complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent employs a composite molecular structure combining pyrene and triphenylamine through condensation reaction, creating a novel condensed-cyclic compound that integrates the beneficial properties of both parent compounds: pyrene provides high quantum efficiency and excellent stability, while triphenylamine contributes good hole transport capability and high mobility, thereby achieving high quantum efficiency without significantly increasing device complexity

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies molecular parameters by introducing specific substituents (such as fluorine atoms at positions 2 and 7 of the pyrene ring) and adjusting the conjugation system of the compound, which changes the electronic structure and optical properties to achieve higher quantum efficiency and light-emitting efficiency while maintaining structural simplicity

Inventive Principle:

Principle #35Parameter changes

2Illumination intensity

If conventional emission layer materials are used, then the manufacturing process is simple, but the brightness and lifespan are insufficient

Engineering Contradiction:

ImprovebrightnessVSAvoidmaterial selection complexity

Core Design Contradiction:

Illumination intensityVSEase of manufacture

Solution Approach 1:

The patent optimizes key molecular parameters including HOMO-LUMO energy gap, carrier mobility, and glass transition temperature by designing the condensed-cyclic compound structure, achieving high brightness through enhanced light-emitting efficiency while ensuring the material remains manufacturable through conventional OLED fabrication processes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent achieves superior performance by directly synthesizing the optimized condensed-cyclic compound through a one-step condensation reaction between pyrene and triphenylamine, skipping the need for complex multi-step synthesis or extensive material screening, thereby maintaining ease of manufacture while achieving high brightness

Inventive Principle:

Principle #21Skipping (Rushing through)

3Duration of action of moving object

If traditional organic compounds are used, then the driving voltage can be maintained, but the lifespan is limited

Engineering Contradiction:

ImprovelifespanVSAvoiddriving voltage

Core Design Contradiction:

Duration of action of moving objectVSUse of energy by moving object

Solution Approach 1:

The patent creates a composite molecular structure where the pyrene-triphenylamine condensed-cyclic compound combines the excellent stability of pyrene with the high mobility of triphenylamine, achieving extended OLED lifespan through improved material stability and reduced degradation while maintaining acceptable driving voltage levels

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent uses readily available starting materials (pyrene and triphenylamine) that are commercially accessible and easy to handle, synthesizing a durable compound through a simple condensation reaction, thereby achieving long lifespan without requiring complex or expensive materials

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 OLEDs with lower driving voltage, higher brightness, and longer lifespan, along with improved quantum yield and light-emitting efficiency.

Implementation Method 1

When a voltage is applied between the anode and the cathode, holes injected from the anode move to the EML via the HTL, and electrons injected from the cathode move to the EML via the ETL. The holes and electrons recombine in the EML to generate excitons. When the excitons drop from an excited state to a ground state, light is emitted.

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

Methodology Applied

Scientific Effectπ-conjugation system:

Data Source

PatentEP2535331B1Condensed-Cyclic Compound and Organic Light-Emitting Diode Comprising the Same

Publication Date: 2016.05.11 SAMSUNG DISPLAY CO LTD

Figure 1

AI summary

The present invention provides a condensed-cyclic compound represented by Formula 1 below and an organic light-emitting diode including the condensed-cyclic compound: