Organometallic Blue OLED Emission Layer for Low-Voltage Color Purity

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Solution Overview

Problem

Current light-emitting devices face challenges in achieving optimal performance in terms of driving voltage, color purity, and lifespan, particularly in emitting blue light with high efficiency and purity.

Innovation Solution

Incorporating an organometallic compound represented by Formula 1, which includes platinum (Pt), palladium (Pd), or gold (Au) as the metal component, within the emission layer of the light-emitting device, along with other compounds to form an exciplex, enhancing the energy gap and molecular stability, thereby reducing driving voltage and improving luminescence efficiency and color purity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional emission layer materials are used, then device structure is simple, but driving voltage is high and luminescence efficiency is low

Engineering Contradiction:
Improvedriving voltageVSAvoidemission layer composition
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The emission layer employs a composite system comprising an exciplex-forming compound (Formula 1) and a host compound (Formula 2), where the exciplex complex between these two materials enables efficient energy transfer and reduced driving voltage while maintaining structural organization

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If conventional emission materials are used, then manufacturing is simple, but color purity is insufficient especially for blue light

Engineering Contradiction:
Improvecolor purityVSAvoidemission layer formulation
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention optimizes the energy gap parameter between the exciplex-forming compound and host compound, ensuring the energy gap is 0.1-2.0 eV, which enables precise control over emission wavelength and achieves high color purity in the blue region (430-480 nm)

Inventive Principle:
Principle #35Parameter changes

3Duration of action of stationary object

If conventional emission layer compounds are used, then device lifespan is limited, but using stable compounds increases driving voltage

Engineering Contradiction:
Improvedevice lifespanVSAvoiddriving voltage
Core Design Contradiction:
Duration of action of stationary objectVSPower

Solution Approach 1:

The host compound acts as an intermediary that accepts energy from the exciplex-forming compound and facilitates efficient energy transfer to generate light emission, while the exciplex complex itself serves as an intermediary state that enables low-voltage operation and high efficiency simultaneously

Inventive Principle:
Principle #24Intermediary (Mediator)

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 organometallic compound in the light-emitting device decreases driving voltage, increases photoluminescence quantum yield, and enhances the device's lifespan while maintaining high efficiency and color purity, particularly in emitting blue light within the 430 nm to 480 nm range.

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

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

Incorporating an organometallic compound represented by Formula 1, which includes platinum (Pt), palladium (Pd), or gold (Au) as the metal component, within the emission layer of the light-emitting device, along with other compounds to form an exciplex, enhancing the energy gap and molecular stability, thereby reducing driving voltage and improving luminescence efficiency and color purity.

Methodology Applied
Scientific EffectExciplex formation:

Data Source

PatentEP4529393A1Light-emitting device including organometallic compound, electronic apparatus including the light-emitting device, and the organometallic compound
Publication Date: 2025.03.26 SAMSUNG DISPLAY CO LTD
  • EP4529393A1 patent drawingFigure 1
  • EP4529393A1 patent drawingFigure 2~3
  • EP4529393A1 patent drawingFigure 4~5

AI summary

A light-emitting device includes a first electrode, a second electrode facing the first electrode, and an interlayer between the first electrode and the second electrode and including an organometallic compound represented by Formula 1. In addition, there are provided an electronic apparatus including the light-emitting device, and the organometallic compound represented by Formula 1.