Organic Light-Emitting Device Auxiliary Layer Triplet Quenching

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Solution Overview

Problem

Organic light-emitting devices face challenges in improving the lifespan and efficiency due to triplet excitons concentrated in the light emission zone, which affect the device's performance and efficiency.

Innovation Solution

Incorporating an auxiliary layer with a material having a lowest excitation triplet energy level within a specific range between the emission layer and the hole blocking layer, which reduces triplet exciton concentration through triplet quenching, thereby enhancing the device's efficiency and lifespan without increasing the driving voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If triplet excitons are concentrated in the light emission zone, then light emission efficiency is improved, but device lifespan deteriorates due to exciton accumulation

Engineering Contradiction:

Improvelight emission efficiencyVSAvoiddevice lifespan

Core Design Contradiction:

ProductivityVSDuration of action of stationary object

Solution Approach 1:

An auxiliary layer is introduced as an intermediary component between the emission layer and electron transport region. This auxiliary layer contains materials with specific triplet energy levels that act as mediators to manage triplet exciton distribution, allowing efficient light emission while preventing harmful exciton accumulation through controlled energy transfer

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the energy level parameters of the auxiliary layer materials, specifically selecting compounds with triplet energy levels (T1) in the range of 2.7-3.2 eV. By changing these energy level parameters, the auxiliary layer can effectively quench triplet excitons and transfer them to safer energy states, resolving the contradiction between emission efficiency and device lifespan

Inventive Principle:

Principle #35Parameter changes

2Reliability

If auxiliary layer materials with specific triplet energy levels are used, then triplet exciton concentration is reduced, but device complexity increases

Engineering Contradiction:

Improvedevice efficiency and lifespanVSAvoidlayer structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of redesigning the entire device structure, the patent applies a partial solution by adding only a thin auxiliary layer (5-50 nm) with specific properties. This partial action approach maintains the overall simple structure while achieving the desired exciton management function, minimizing the increase in device complexity

Inventive Principle:

Principle #16Partial or excessive action

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 auxiliary layer effectively disperses triplet excitons and blocks excitons from moving to the electron transport region, improving the organic light-emitting device's efficiency and lifespan by reducing triplet exciton concentration at the emission zone.

Implementation Method 1

Methodology Applied

Scientific EffectTriplet quenching:

Implementation Method 2

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

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS20200274073A1Organic light-emitting device

Publication Date: 2020.08.27 SAMSUNG DISPLAY CO LTD

AI summary

Provided is an organic light-emitting device including an auxiliary layer between an emission layer and a hole blocking layer.