Organic Functional Compounds for OLED Solvent Barrier Layers

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Solution Overview

Problem

Current solution-processed OLED devices face issues with interface miscibility and interface corrosion due to the solubility of organic materials in solvents, limiting their performance and requiring vacuum evaporation methods for certain layers, while crosslinkable polymers with lower triplet energy levels are not effective as exciton blocking layers.

Innovation Solution

An organic functional compound with a specific formula is developed, capable of undergoing a Bergman cycloaromatization reaction to form a solvent-insoluble layer, which is used to prepare functional layers for OLEDs via solution processing, avoiding miscibility and corrosion issues and enabling higher triplet energy levels for exciton blocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If solution processing method is used to prepare multi-layer OLED, then manufacturing cost is reduced and large-area production is enabled, but interface miscibility and interface corrosion problems occur due to solvent solubility

Engineering Contradiction:

Improvemanufacturing costVSAvoidinterface stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent converts the harmful effect of solvent solubility (which causes interface miscibility and corrosion) into a beneficial feature by designing the hole transport layer material with specific solubility characteristics. The material is soluble in the first solvent (toluene, chloroform, or chlorobenzene) used for the light emitting layer, allowing it to serve as a solvent barrier that prevents underlying layer dissolution while maintaining solution-processability for low-cost manufacturing

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the chemical structure parameters of the hole transport layer material by incorporating specific moieties (carbazole, triphenylamine, or dibenzofuran) and substituents (fluoroalkyl, deuterated alkyl, or deuterated fluoroalkyl groups) to achieve optimal solubility in the first solvent. This parameter optimization enables the material to function as an effective solvent barrier while maintaining compatibility with solution processing methods

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional crosslinking groups are used in polymer HTM, then solvent resistance is improved, but triplet energy level is reduced making them ineffective as exciton blocking layers

Engineering Contradiction:

Improvesolvent resistanceVSAvoidtriplet energy level

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent creates a composite material system by combining the hole transport layer material with a crosslinking agent that has high triplet energy level. The crosslinking agent (containing styryl, perfluorocyclobutane, epoxybutane, silicone, acrylate, or benzocyclobutane groups) provides solvent resistance through crosslinking, while the high triplet energy level of the crosslinking agent enables exciton blocking functionality that conventional low-triplet-energy polymers cannot achieve

Inventive Principle:

Principle #40Composite materials

3Reliability

If vacuum evaporation method is used to obtain multi-layer OLED, then device performance is improved, but manufacturing cost increases and large-area application becomes difficult

Engineering Contradiction:

Improvedevice performanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the vacuum evaporation method (mechanical/physical deposition process) with solution processing methods (chemical dissolution and deposition). By designing the hole transport layer material with appropriate solubility in the first solvent, the patent enables deposition via inkjet printing, spin coating, or other solution-based techniques, achieving both high device performance and low manufacturing cost with large-area production capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 organic functional compound allows for the formation of high-performance OLED devices with improved exciton blocking capabilities and solvent resistance, enabling large-area, flexible, and cost-effective production through solution processing methods.

Implementation Method 1

capable of undergoing a Bergman cycloaromatization reaction to form a solvent-insoluble layer

Methodology Applied

Scientific EffectBergman cycloaromatization reaction:

Implementation Method 2

the crosslinking group on the polymer initiates cross-linking reaction of the crosslinkable groups such as the perfluorocyclobutane group under conditions of light, heat, and the like, forming an insoluble and infusible interpenetrating network polymer film with excellent solvent resistance

Methodology Applied

Scientific EffectCrosslinking reaction:

Data Source

PatentUS11404644B2Organic functional compounds, mixtures, formulations, organic functional thin films and preparation methods therefor and organic electronic devices

Publication Date: 2022.08.02 GUANGZHOU CHINARAY OPTOELECTRONICS MATERIALS LTD

AI summary

An organic functional compound, having a general formula of ASG)p; wherein A is an organic group having an optoelectronic function; the structural formula of SG is selected from the group consisting ofwhereinis selected from the group consisting of an aryl containing 5-40 ring-forming atoms and a heteroaryl containing 5-40 ring-forming atoms; R1 and R2 are each independently selected from the group consisting of H, D, F, CN, an alkyl, an aromatic ring group, an aromatic heterocyclic group, an amino, a silyl, a germyl, an alkoxy, an aryloxy, and a siloxy group; and p is an integer greater than or equal to 1.