Polycyclic Compound Hole Transport Layer Exciton Energy Management

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Solution Overview

Problem

Current light emitting elements face challenges in achieving high emission efficiency and long device life while maintaining low driving voltage, particularly in suppressing exciton energy diffusion outside the emission layer.

Innovation Solution

A polycyclic compound is introduced for use in the hole transport region of light emitting elements, specifically represented by Formula 1, which includes various substituents and bonding configurations to enhance hole transport and injection properties, thereby improving emission efficiency and device longevity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional hole transport materials are used, then the device structure is simple, but exciton energy diffuses outside the emission layer reducing emission efficiency

Engineering Contradiction:

Improveexciton energy diffusionVSAvoiddevice structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent introduces a hole transport region comprising multiple layers (hole injection layer, hole transport layer, electron blocking layer) that act as intermediaries to manage exciton energy. These layers prevent exciton energy from diffusing into the hole transport region by creating energy barriers, thereby resolving the contradiction between preventing energy loss and maintaining structural simplicity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If materials that suppress exciton energy diffusion are introduced, then emission efficiency improves, but driving voltage increases

Engineering Contradiction:

Improveemission efficiencyVSAvoiddriving voltage

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent carefully selects materials with specific energy level parameters for each layer in the hole transport region. By optimizing the HOMO and LUMO energy levels of the hole injection layer, hole transport layer, and electron blocking layer, the patent achieves effective exciton energy confinement while maintaining acceptable driving voltage through parameter optimization rather than structural complexity.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If advanced hole transport materials are used, then emission efficiency increases, but device life decreases

Engineering Contradiction:

Improveemission efficiencyVSAvoiddevice life

Core Design Contradiction:

ProductivityVSDuration of action of stationary object

Solution Approach 1:

The patent employs a composite structure in the hole transport region with multiple layers having different material compositions and functions. This composite approach allows each layer to be optimized for its specific function (hole injection, hole transport, electron blocking) while working together to achieve both high emission efficiency and long device life through synergistic material combinations.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS20230139741A1Light emitting element and polycyclic compound for the same

Publication Date: 2023.05.04 SAMSUNG DISPLAY CO LTD

AI summary

A light emitting element according to an embodiment includes a first electrode, a second electrode disposed on the first electrode, and at least one functional layer disposed between the first electrode and the second electrode and including a polycyclic compound according to an embodiment, thereby showing high efficiency and long-life characteristics.