Light-Emitting Device Electron-Transport Layer Crystallization Control
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Solution Overview
Problem
In patterning organic layers for light-emitting devices using photolithography, the application of heat can cause crystallization defects, limiting the achievable resolution due to insufficient curing of the photomask.
Innovation Solution
Incorporating heteroaromatic compounds with heteroaromatic rings and organic compounds in the electron-transport layers, which improves heat resistance and inhibits crystallization, allowing for higher resolution and reliable light-emitting devices with reduced defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat is applied at the time of forming a photomask, then the photomask can be properly cured, but crystallization defects occur in the organic layer
Solution Approach 1:
The patent modifies the chemical composition parameters of the electron-transport layer by incorporating heteroaromatic compounds with specific molecular structures. This changes the thermal properties of the layer, raising its crystallization temperature and allowing it to withstand photomask curing heat without crystallizing, thus resolving the contradiction between proper photomask curing and prevention of crystallization defects
Solution Approach 2:
The patent creates a composite electron-transport layer by combining heteroaromatic compounds (such as those containing triazine, pyrimidine, or pyridine rings) with other organic compounds. This composite structure provides both the thermal stability needed to resist crystallization during heating and the proper electron-transport functionality, simultaneously achieving photomask curing reliability and defect prevention
2Object-affected harmful factors
If heat application is reduced to prevent crystallization, then crystallization defects are reduced, but resolution is insufficient due to inadequate photomask curing
Solution Approach 1:
By changing the chemical composition parameters of the electron-transport layer to include heteroaromatic compounds with high thermal stability, the patent enables the layer to maintain its amorphous state at higher temperatures. This allows sufficient heat application for complete photomask curing while preventing crystallization, thus achieving both high resolution patterning and defect reduction
Solution Approach 2:
The patent applies local quality by specifically designing the electron-transport layer with heteroaromatic compounds that have different thermal properties than conventional organic compounds. This localized modification of material properties in the electron-transport region enables it to withstand curing temperatures without crystallization, allowing high-resolution patterning without the compromise of reduced heat application
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 use of heteroaromatic compounds and organic compounds in electron-transport layers enhances the heat resistance and electron-transport properties, enabling higher resolution and more reliable light-emitting devices with improved patterning capabilities and reduced crystallization defects.
Implementation Method 1
crystallization proceeds at a low temperature owing to its stacked-layer structure in some cases, which might cause a defect, crystallization of the organic layer due to the heat applied at the time of forming the photomask
Implementation Method 2
heat is sometimes applied at the time of forming a photomask
Implementation Method 3
Light-emitting devices (organic EL devices) including organic compounds and utilizing electroluminescence (EL) have been put to more practical use. Carriers are injected by application of a voltage to the device, and recombination energy of the carriers is used, whereby light emission can be obtained from the light-emitting material
Data Source
AI summary
A light-emitting device with a high resolution and favorable characteristics manufactured by a photolithography method is provided. In the light-emitting device, a first light-emitting device and a second light-emitting device are adjacent each other. The first light-emitting device includes a first EL layer, and the second light-emitting device includes a second EL layer. The first EL layer includes at least a first light-emitting layer and a first electron-transport layer, and the second EL layer includes at least a second light-emitting layer and a second electron-transport layer. The first electron-transport layer contains a first heteroaromatic compound and a first organic compound, and the second electron-transport layer contains a second heteroaromatic compound and a second organic compound. Edge portions of the first light-emitting layer and the first electron-transport layer are aligned, and edge portions of the second light-emitting layer and the second electron-transport layer are substantially aligned. The distance between the first light-emitting device and the second light-emitting device facing each other is 2 μm to 5 μm.