Light-Emitting Device Host-Guest Emission Layer

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Solution Overview

Problem

Current light-emitting devices face limitations in emission efficiency and lifespan characteristics, particularly in achieving balanced hole and electron injection and efficient light generation.

Innovation Solution

A composition comprising specific first and second compounds, along with a transition metal-containing compound or delayed fluorescence compound, is used to form a layer in a light-emitting device, optimizing phase transition temperatures and energy levels for improved emission efficiency and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional emission layers are used, then device structure is simple, but emission efficiency is insufficient

Engineering Contradiction:

Improveemission efficiencyVSAvoidemission layer structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The emission layer uses a composite material system comprising a host compound and a guest compound (phosphorescent or fluorescent material). This composite structure enables efficient energy transfer from the host to the guest, achieving high emission efficiency while maintaining a relatively simple two-component system that can be deposited using conventional vacuum deposition techniques.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes emission efficiency by carefully selecting and adjusting key parameters including the triplet energy level (T1) of the host compound, the phosphorescence quantum efficiency, and the concentration ratio of host to guest compounds. These parameter optimizations enable efficient phosphorescence emission without requiring complex device structures.

Inventive Principle:

Principle #35Parameter changes

2Duration of action of stationary object

If conventional emission layers are used, then manufacturing process is simple, but lifespan characteristics are limited

Engineering Contradiction:

Improvelifespan characteristicsVSAvoidmanufacturing process

Core Design Contradiction:

Duration of action of stationary objectVSEase of manufacture

Solution Approach 1:

The emission layer employs a composite material system with a host compound and guest compound where the host provides structural stability and the guest provides phosphorescence emission. This composite structure enhances device lifespan by improving material stability and reducing degradation, while the materials can still be deposited using standard vacuum deposition processes.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent extends device lifespan by optimizing the triplet energy level of the host compound to be higher than that of the guest compound, preventing energy back-transfer and degradation. The phosphorescence quantum efficiency and compound concentration ratios are also optimized to enhance material stability during operation, all while maintaining compatibility with conventional manufacturing processes.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If balanced hole and electron injection is achieved, then emission efficiency improves, but device complexity increases

Engineering Contradiction:

Improveemission efficiencyVSAvoidinjection control mechanism

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent achieves balanced carrier injection by selecting materials with specific HOMO and LUMO energy levels that are locally optimized for the emission layer. The host compound and guest compound are chosen with complementary energy levels that facilitate balanced hole and electron injection, eliminating the need for complex external injection control mechanisms.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent optimizes emission efficiency by adjusting key energy level parameters including the HOMO and LUMO values of the host and guest compounds. By carefully selecting compounds with appropriate energy level alignments, balanced carrier injection is achieved inherently through material selection rather than complex device structure, maintaining simplicity while improving performance.

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 composition enhances emission efficiency and lifespan characteristics by ensuring balanced hole and electron injection, leading to improved electrical characteristics and durability in light-emitting devices.

Implementation Method 1

Holes provided from the first electrode move toward the emission layer through the hole transport region, and electrons provided from the second electrode move toward the emission layer through the electron transport region. 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 to thereby generate light.

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

Methodology Applied

Scientific EffectPhase transition: Phase Change

Data Source

PatentUS20240196637A1Composition, light-emitting device, and electronic device including light-emitting device

Publication Date: 2024.06.13 SAMSUNG DISPLAY CO LTD

AI summary

Provided are a composition including a first compound represented by Formula 1 and a second compound represented by Formula 2, a light-emitting device, and an electronic device and an apparatus each including the light-emitting device. Formulae 1 and 2 are the same as described in the specification.