Spiroxanthene Matrix Materials for OLED Efficiency and Lifetime

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Solution Overview

Problem

Organic electroluminescent devices (OLEDs) face challenges in efficiency, operating voltage, and service life, particularly with triplet emission phosphorescent OLEDs, where existing matrix materials do not fully address these issues.

Innovation Solution

Development of specific spiroxanthene compounds with a fused carbazole unit and oxygen or sulfur bridges, which serve as matrix materials for phosphorescent emitters, enhancing charge transport properties and device performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional matrix materials (indolocarbazole, indenocarbazole, fluorene, spirobifluorene derivatives) are used in phosphorescent OLEDs, then device structure and material selection are established, but efficiency, lifetime, and operating voltage performance are insufficient

Engineering Contradiction:

Improvedevice lifetimeVSAvoiddevice efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent modifies the molecular structure of matrix materials by introducing spiroxanthene core with fused carbazole units and oxygen/sulfur bridges, changing the chemical and physical parameters of the material to achieve simultaneous improvement in efficiency, lifetime, and operating voltage characteristics

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates composite molecular structures combining spiroxanthene, carbazole, and heteroatom bridge components to develop new matrix materials that exhibit superior charge transport properties and device performance compared to conventional single-structure materials

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If phosphorescent emitters are used in OLEDs, then energy efficiency can be up to four times higher than fluorescence, but operating voltage and lifetime remain problematic

Engineering Contradiction:

Improveenergy efficiencyVSAvoidoperating voltage

Core Design Contradiction:

Use of energy by moving objectVSUse of energy by stationary object

Solution Approach 1:

The patent changes the energy transport and charge carrier mobility parameters of the matrix material through molecular structure optimization, enabling better control of operating voltage while maintaining the high energy efficiency of phosphorescent emission

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If existing matrix materials are used, then material selection is limited, but charge transport properties and device performance cannot be optimized further

Engineering Contradiction:

Improvematerial selection rangeVSAvoidcharge transport properties

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces specific functional groups and structural features (oxygen/sulfur bridges, fused carbazole units) at specific positions within the spiroxanthene core to locally enhance charge transport properties while maintaining overall material versatility

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

By systematically varying the spiroxanthene derivative structures with different substituents and bridge types, the patent expands material selection while optimizing charge transport parameters for improved device reliability

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP3160954B1Materials for organic electroluminescent devices

Publication Date: 2020.09.23 MERCK PATENT GMBH

AI summary

The invention relates to compounds which are suitable for use in electronic devices, and to electronic devices, in particular organic electroluminescent devices, containing said compounds.