Phosphorescent OLED Organic Layer for Extended Device Lifetime

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Solution Overview

Problem

Existing organic electroluminescent devices face challenges with non-saturated emitting colors, high operating voltages, short device lifetimes, and efficiency roll-off at high brightness, particularly in blue phosphorescent devices, limiting their commercialization and performance.

Innovation Solution

Incorporating a first metal complex with a specific ligand structure of Formula 1 and a first compound with a structure of Formula 2 into the organic electroluminescent device, enhancing the device's performance, especially its lifetime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If phosphorescent emitters are used in OLEDs, then internal quantum efficiency can reach 100%, but device lifetime remains short and operating voltage is high

Engineering Contradiction:

Improveinternal quantum efficiencyVSAvoiddevice lifetime

Core Design Contradiction:

Use of energy by moving objectVSDuration of action of stationary object

Solution Approach 1:

The patent modifies the molecular structure of phosphorescent emitters by introducing specific ligand configurations (Formula 1) and compound structures (Formula 2), changing chemical parameters to achieve both high efficiency and long lifetime. The structural modifications optimize the emitter properties without sacrificing quantum efficiency.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses composite material systems combining specially designed phosphorescent emitters with host materials and doping agents. This composite approach allows synergistic effects where the emitter-complex-host system achieves both 100% IQE and extended device lifetime simultaneously.

Inventive Principle:

Principle #40Composite materials

2Shape

If phosphorescent emitters are used to achieve saturated blue color, then color saturation improves, but device lifetime shortens and operating voltage increases

Engineering Contradiction:

Improveemitting color saturationVSAvoiddevice lifetime

Core Design Contradiction:

ShapeVSDuration of action of stationary object

Solution Approach 1:

The patent achieves saturated blue emission by precisely controlling the molecular parameters of the phosphorescent emitter, including ligand field strength and molecular geometry. These parameter optimizations enable color saturation while simultaneously improving device stability and lifetime through the same structural modifications.

Inventive Principle:

Principle #35Parameter changes

3Illumination intensity

If high brightness is achieved in phosphorescent OLEDs, then luminance output increases, but efficiency roll-off occurs

Engineering Contradiction:

Improveluminance outputVSAvoidelectrical efficiency

Core Design Contradiction:

Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent employs partial action by using doping concentrations and excitation conditions that prevent excessive triplet-triplet annihilation and exciton-polaron interactions. This approach maintains high electrical efficiency even at elevated luminance levels by operating in an optimized parameter regime.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The invention modifies key parameters including emitter concentration, host-guest ratio, and energy level alignment to suppress efficiency roll-off mechanisms. These parameter changes enable the device to maintain high electrical efficiency across a broader luminance range.

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 integration of the metal complex and compound significantly improves the device's overall performance, particularly extending its lifetime and potentially addressing issues of non-saturated colors and efficiency roll-off.

Implementation Method 1

In 1997, Forrest and Thompson reported phosphorescent OLED, which uses triplet emission from heavy metal containing complexes as the emitter

Methodology Applied

Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 2

Recently, Adachi achieved high efficiency through thermally activated delayed fluorescence (TADF) of organic compounds. These emitters have small singlet-triplet gap that makes the transition from triplet back to singlet possible. In the TADF device, the triplet excitons can go through reverse intersystem crossing to generate singlet excitons

Methodology Applied

Scientific EffectThermally activated delayed fluorescence:

Data Source

PatentUS20250311528A1Organic electroluminescent device, organic layer, display assembly, and electronic device

Publication Date: 2025.10.02 BEIJING SUMMER SPROUT TECH CO LTD

AI summary

Provided is an organic electroluminescent device and, in particular, an organic electroluminescent device comprising a metal complex having a ligand structure of Formula 1 and a first compound having a structure of Formula 2, an organic layer comprising the metal complex and the first compound, and a display assembly and electronic device comprising the organic electroluminescent device or organic layer. The organic electroluminescent device comprises an anode, a cathode, and an organic layer disposed between the anode and the cathode, wherein the organic layer comprises at least a first metal complex and a first compound; the first metal complex comprises a metal M and a ligand La coordinated to the metal Ma and La has a structure represented by Formula 1; and the first compound has a structure represented by Formula 2. The device has relatively good overall device performance, especially an improved device lifetime.