Condensed Cyclic Compound for OLED Driving Voltage Reduction

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Solution Overview

Problem

Organic light-emitting devices (OLEDs) face challenges in achieving low driving voltage, high efficiency, high brightness, and long lifespan.

Innovation Solution

A novel condensed cyclic compound represented by Formula 1 is introduced, which is incorporated into the organic layer of OLEDs, exhibiting a relatively low highest occupied molecular orbital (HOMO) energy level and a high triplet state T1 energy level, enhancing hole injection and transport characteristics and luminous efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional organic compounds are used in OLEDs, then device structure and operation are maintained, but driving voltage remains high and efficiency is limited

Engineering Contradiction:

Improvedriving voltageVSAvoidmolecular structure complexity

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by modifying the molecular structure of organic compounds used in OLEDs. Specifically, it introduces condensed cyclic compounds with specific HOMO energy levels and triplet state T1 energy levels. By changing these molecular parameters (energy levels, cyclic structure), the patent achieves lower driving voltage and higher efficiency without significantly increasing device structural complexity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by combining specific functional groups within the condensed cyclic compound structure. The molecule integrates electron-transporting moieties, hole-transporting moieties, and specific cyclic structures (dibenzofuran, dibenzothiophene) to create a multifunctional material that simultaneously improves voltage characteristics and efficiency

Inventive Principle:

Principle #40Composite materials

2Productivity

If conventional organic compounds are used in OLEDs, then device operation is maintained, but luminous efficiency and power efficiency remain suboptimal

Engineering Contradiction:

Improveluminous efficiencyVSAvoidenergy efficiency

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent changes key molecular parameters including HOMO energy level and triplet state T1 energy level to optimize efficiency. By selecting compounds with specific energy level ranges and introducing condensed cyclic structures, the patent reduces energy loss and improves luminous efficiency and power efficiency simultaneously

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the typically harmful triplet excitons into beneficial light-emitting states by utilizing materials with appropriate triplet energy levels. The condensed cyclic compound structure enables triplet state utilization that previously represented energy loss, transforming it into enhanced luminous efficiency

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If conventional organic compounds are used in OLEDs, then basic device function is achieved, but hole injection and transport characteristics are insufficient

Engineering Contradiction:

Improvehole injection characteristicVSAvoidmolecular structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent optimizes hole injection characteristics by adjusting molecular parameters such as HOMO energy level and introducing specific functional groups (carbazolyl, pyridinyl) that facilitate hole transport. These parameter changes improve reliability of hole injection without requiring complex device architecture

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The condensed cyclic compound serves multiple functions simultaneously: it provides hole transport capability, electron transport capability, and appropriate energy level alignment. This multi-functionality improves hole injection characteristics while avoiding the need for additional complex molecular structures or separate functional layers

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 in OLEDs results in devices with low driving voltage, high luminous efficiency, high power efficiency, and long lifespan.

Implementation Method 1

exhibiting a relatively low highest occupied molecular orbital (HOMO) energy level and a high triplet state T1 energy level, enhancing hole injection and transport characteristics

Methodology Applied

Scientific EffectHole injection and transport:

Implementation Method 2

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

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS10580997B2Condensed cyclic compound and organic light-emitting device including the same

Publication Date: 2020.03.03 SAMSUNG ELECTRONICS CO LTD

AI summary

A condensed cyclic compound represented by Formula 1:wherein in Formula 1, a1, a2, Ar1, Ar2, R1, and R2 are the same as described in the specification.