Light-Emitting Device Interception Layer Fluorine Management
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Solution Overview
Problem
Conventional EL display devices experience increased contact resistance between the power supply wire and the common electrode due to fluorine from bank material dross, leading to decreased voltage supply and brilliance variation across the light-emitting layer.
Innovation Solution
A light-emitting device structure incorporating a transition metal oxide layer, an interception layer to block migrating fluorine, and an organic layer doped with alkali metal, which separates the bank material dross and prevents fluoridation of the alkali metal, thereby constraining the increase in contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a power supply wire is used to supply electricity to the common electrode, then voltage supply stability is improved, but contact resistance increases due to fluorine from bank material dross
Solution Approach 1:
An interception layer made of aluminum oxide or aluminum hydroxide is introduced between the bank material dross and the organic electron transport layer. This intermediary layer captures fluorine atoms that migrate from the bank material, preventing them from reaching and fluoridating the alkali metal in the organic layer, thus maintaining low contact resistance while preserving voltage supply stability
Solution Approach 2:
The harmful fluorine atoms migrating from the bank material dross are converted into beneficial aluminum fluoride compounds within the interception layer. By allowing fluorine to react with the aluminum oxide/aluminum hydroxide interception layer instead of reaching the organic electron transport layer, the harmful fluorine is transformed into a stable compound that protects the device
2Illumination intensity
If ITO is used as transparent conductive material in the common electrode, then transparency is improved, but electrical conductivity deteriorates due to high resistance
Solution Approach 1:
The common electrode is constructed as a composite structure combining ITO (for transparency) with an organic electron transport layer doped with alkali metal and an aluminum oxide/aluminum hydroxide interception layer. This composite structure achieves both high transparency from the ITO and improved electrical conductivity through the organic layer, while the interception layer ensures stable electrical properties by preventing fluorine-induced contact resistance
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 solution effectively reduces contact resistance and maintains consistent voltage supply to the common electrode, minimizing brilliance variation and ensuring stable light emission.
Implementation Method 1
an interception layer formed on a portion of the transition metal oxide layer that is exposed through the opening, and intercepting migrating fluorine
Data Source
AI summary
A light-emitting device comprises a substrate, a light-emitting layer, a wire formed on the substrate and supplying electric power to the light-emitting layer; a transition metal oxide layer formed on the substrate and over the wire; a bank formed on the transition metal oxide layer defining an opening over the wire; an interception layer formed on a portion of the transition metal oxide layer that is exposed through the opening and intercepting migrating fluorine; an organic layer formed on the interception layer and doped with an alkali metal; and an electrode formed on the organic layer, electrically connected to the wire via the organic layer, the interception layer, and the transition metal oxide layer, and providing the electric power supplied by the wire to the organic layer.