Light-Emitting Device Block Layer Oxidation Prevention
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Solution Overview
Problem
Existing light-emitting devices face challenges with oxidation and electrical continuity issues, leading to increased driving voltage over time and reduced reliability, especially in high-resolution displays where crosstalk narrows the displayable color gamut.
Innovation Solution
A light-emitting device structure featuring a second electrode over a first electrode with an EL layer sandwiched in between, including an oxidation-resistant layer and a block layer to prevent oxidation and electrical continuity, using materials like molybdenum oxide and organic compounds with electron-withdrawing groups, and a block layer with a hole-transport material to manage electrical flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the EL layer is exposed to the atmosphere during manufacturing, then the manufacturing process becomes simpler, but oxidation of the EL layer occurs leading to increased driving voltage and reduced reliability
Solution Approach 1:
A block layer comprising a hole-transport material is introduced as an intermediary between the EL layer and the atmosphere during manufacturing. This block layer prevents oxidation of the EL layer when exposed to atmosphere, while being removable afterward, thus enabling both simplified manufacturing and maintained reliability
2Device complexity
If the second electrode is in direct contact with the side surface of the EL layer, then device structure is simplified, but electrical continuity occurs between electrodes causing short circuit
Solution Approach 1:
The block layer serves as an intermediary that prevents electrical continuity between the second electrode and the EL layer side surface. It provides electrical insulation while allowing the simplified structure of direct contact to be maintained, and can be selectively removed in non-critical areas
3Reliability
If oxidation prevention measures are implemented, then device reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The block layer acts as a temporary intermediary that provides oxidation protection during manufacturing without requiring complex vacuum or inert atmosphere systems. After serving its protective function, it can be selectively removed, thus providing reliability improvement with minimal permanent structural complexity
Solution Approach 2:
The block layer is applied selectively to specific areas where oxidation protection is needed during manufacturing, rather than requiring comprehensive protection measures across the entire device structure, thus maintaining local quality while avoiding unnecessary complexity
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 provides a reliable and efficient light-emitting device with low driving voltage, reduced oxidation risk, and enhanced color gamut in high-resolution displays by preventing electrical continuity and oxidation, thus improving device stability and performance.
Implementation Method 1
The oxidation-resistant layer can prevent oxidation of the EL layer even in the case where the EL layer is exposed to the atmosphere
Implementation Method 2
the block layer can prevent electrical continuity between the first electrode and the second electrode
Data Source
AI summary
A novel light-emitting device that is highly convenient, useful, or reliable is provided. A light-emitting device including a second electrode over a first electrode with an EL layer sandwiched therebetween is provided. The EL layer includes a light-emitting layer and an oxidation-resistant layer over the light-emitting layer. The EL layer includes a side surface. The light-emitting device includes a block layer in contact with a top surface and the side surface of the EL layer. The second electrode is in contact with the side surface of the EL layer through the block layer. The oxidation-resistant layer includes any one or a plurality of oxides of metals belonging to Group 4 to Group 8 of the periodic table and an organic compound having an electron-withdrawing group.