Organic Electroluminescent Material for OLED Efficiency

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Solution Overview

Problem

Current organic electroluminescence (EL) devices face challenges with shorter half-life times, lower efficiency, and higher power consumption, particularly in phosphorescent dopants used for full-colored flat panel displays and OLED lighting, where conventional materials fail to efficiently transport charges and block holes effectively, leading to suboptimal performance.

Innovation Solution

A novel material with a specific formula is introduced, serving as a phosphorescent emitting host, delayed fluorescent dopant, and hole blocking layer (HBL) for organic EL devices, enhancing charge carrier mobility, thermal stability, and operational durability, thereby reducing driving voltage and power consumption while increasing efficiency and half-life time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If conventional phosphorescent dopants are used in organic EL devices, then the device can emit light, but the half-life time is short and efficiency is low

Engineering Contradiction:

Improvehalf-life timeVSAvoidluminance efficiency

Core Design Contradiction:

Duration of action of stationary objectVSProductivity

Solution Approach 1:

The patent modifies the molecular structure of phosphorescent dopants by introducing specific substituents (carbazolyl, dibenzofuranyl, dibenzothiophenyl groups) to change the energy levels and charge transport properties, thereby improving both half-life time and luminance efficiency simultaneously

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials combining organic metallic complexes with specific ligand structures (formulas 1 and 2) that integrate both phosphorescent emission and charge transport capabilities, resolving the contradiction between durability and efficiency

Inventive Principle:

Principle #40Composite materials

2Reliability

If conventional phosphorescent dopants are used, then the device can operate, but power consumption is high

Engineering Contradiction:

Improveoperational durabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the HOMO and LUMO energy levels of the phosphorescent dopant molecules to improve charge injection efficiency and reduce energy losses, thereby lowering power consumption while maintaining operational durability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the traditionally harmful non-radiative decay pathways into beneficial charge transport mechanisms by designing molecules with appropriate energy level alignments, reducing energy waste and improving overall device efficiency

Inventive Principle:

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

3Device complexity

If conventional electron transporting layer is used, then the device structure is simple, but hole blocking ability is insufficient

Engineering Contradiction:

Improvelayer structureVSAvoidhole blocking ability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent develops electron transporting materials that simultaneously possess hole blocking capability through specific molecular structures (formulas 3 and 4 with carbazole and triazine groups), eliminating the need for separate HBL and simplifying the overall device structure while maintaining reliability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the functions of electron transport and hole blocking into a single material layer, reducing device complexity while ensuring adequate hole confinement in the emitting layer for improved efficiency

Inventive Principle:

Principle #5Merging (Combining)

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 novel material significantly improves the luminance efficiency, half-life time, and operational durability of organic EL devices, achieving higher performance and efficiency compared to conventional materials, with specific examples demonstrating improved performance in organic EL device testing.

Implementation Method 1

phosphorescent organic EL device make use of spin-orbit interactions to facilitate intersystem crossing between singlet and triplet states, thus obtaining emission from both singlet and triplet states

Methodology Applied

Scientific EffectSpin-orbit interaction:

Implementation Method 2

converting spin-forbidden triplet excitons up to the singlet level by the mechanism of reverse intersystem crossing(RISC)

Methodology Applied

Scientific EffectReverse intersystem crossing:

Implementation Method 3

Methodology Applied

Scientific EffectPhosphorescence: Phosphorescence

Data Source

PatentUS20180315932A1Organic electroluminescent material and using the same

Publication Date: 2018.11.01 LUMINESCENCE TECH

AI summary

There is provided a novel material of formula(1) or formula(2) and the organic EL device employing the novel material as phosphorescent light emitting host of emitting layer, delayed fluorescence dopant of emitting layer, and hole blocking layer can display good performance like as lower driving voltage and power consumption, increasing efficiency and life time of organic EL device.wherein p, X, Z, R1, Ar and A are the same definition as described in the present invention.