Stacked OLED Charge Generation Layer with Dopant-Blocking Interlayer

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Solution Overview

Problem

Stacked organic light-emitting devices face issues with charge generation regions prone to degradation, leading to higher operating voltages, reduced efficiency, and lower durability due to the diffusion of n-dopants in heterocyclic compounds and metal complexes.

Innovation Solution

Incorporating a charge generation layer with a metal atom and an intermediate layer containing a fused polycyclic hydrocarbon compound to inhibit the diffusion of n-type dopants, thereby enhancing the durability of the device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a charge generation region is composed of a heterocyclic compound and a metal complex, then charge generation is achieved, but n-dopant diffusion occurs leading to reduced durability

Engineering Contradiction:

ImprovedurabilityVSAvoidn-dopant diffusion

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces an intermediate layer between the charge generation layer and the second light-emitting layer. This intermediate layer acts as a mediator that blocks the diffusion of n-dopants from the charge generation region into the light-emitting layer, thereby preventing degradation while maintaining charge generation functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The charge generation region is divided into two distinct layers: a charge generation layer containing heterocyclic compound and metal complex, and an intermediate layer containing fused polycyclic hydrocarbon compound. This segmentation allows each layer to perform its specific function - charge generation and dopant blocking, respectively - without interfering with each other.

Inventive Principle:

Principle #1Segmentation

2Illumination intensity

If stacked organic light-emitting devices are used, then light emission is achieved, but driving voltage increases

Engineering Contradiction:

Improvelight emissionVSAvoiddriving voltage

Core Design Contradiction:

Illumination intensityVSStress or pressure

Solution Approach 1:

The patent modifies the chemical composition and energy level parameters of the intermediate layer to optimize charge transport and reduce energy barriers. By selecting fused polycyclic hydrocarbon compounds with appropriate HOMO-LUMO levels, the device achieves lower driving voltages while maintaining efficient light emission.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20260033131A1Organic light-emitting device

Publication Date: 2026.01.29 CANON KK

AI summary

The present disclosure provides an organic light-emitting device including, in this order, a first electrode, a first light-emitting layer, a charge transport layer, a charge generation region including a charge generation layer and an intermediate layer, a second light-emitting layer, and a second electrode, in which the charge generation layer contains a metal atom, the intermediate layer is disposed between the charge generation layer and the second light-emitting layer, and the intermediate layer contains a fused polycyclic hydrocarbon compound.