Organic Light-Emitting Device Electron Injection Layer with Lanthanide Halide
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Solution Overview
Problem
Existing organic light-emitting devices face challenges in reducing driving voltage and enhancing light-emitting efficiency.
Innovation Solution
An organic light-emitting device structure is developed with an electron injection layer comprising a halide of an alkali metal and a lanthanide or alkaline earth metal, and a cathode made of specific metals, where the electron injection layer is formed by co-depositing these materials to improve electron injection efficiency and reduce driving voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional electron injection layers are used, then device structure is simple, but driving voltage is high and electron injection efficiency is low
Solution Approach 1:
The electron injection layer is constructed as a composite material system combining alkali metal halide (first material) with lanthanide or alkaline earth metal (second material). This composite structure enables synergistic effects where the alkali metal halide provides good electron injection properties while the lanthanide/alkaline earth metal enhances electron mobility and reduces driving voltage, achieving both low voltage operation and improved electron injection efficiency without excessive structural complexity
Solution Approach 2:
The invention optimizes specific parameters including the thickness of each layer in the electron injection region (first layer: 1-20 nm, second layer: 0.1-5 nm), the volume ratio of first to second material (1:9 to 9:1), and the composition of cathode metals. These parameter optimizations enable the composite structure to achieve low driving voltage while maintaining manufacturability
2Productivity
If electron injection efficiency is improved through material optimization, then light-emitting efficiency increases, but manufacturing complexity increases
Solution Approach 1:
The electron injection layer is divided into two distinct functional layers: a first layer containing alkali metal halide (3-20 nm thick) for electron injection, and a second layer containing lanthanide or alkaline earth metal (0.1-5 nm thick) for electron mobility enhancement. This segmentation allows each layer to be optimized independently for its specific function while maintaining compatibility with existing vacuum deposition manufacturing processes
Solution Approach 2:
The invention specifies optimal parameter ranges including layer thicknesses (first layer: 1-20 nm, second layer: 0.1-5 nm), material volume ratios (1:9 to 9:1), and cathode metal compositions. These parameter specifications enable consistent high-performance manufacturing while maintaining compatibility with standard vacuum deposition techniques, balancing light-emitting efficiency with ease of manufacture
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 results in improved electron injection efficiency, lower driving voltage, and enhanced light-emitting characteristics, as demonstrated by increased current density at reduced voltage levels.
Implementation Method 1
an electron injection layer including: a first material including at least one of a halide of an alkali metal (Group 1); and a second material including at least one of a lanthanide metal and an alkaline earth metal (Group 2)
Implementation Method 2
the cathode contacts the electron injection layer and includes a first metal including at least one of silver (Ag), gold (Au), platinum (Pt), copper (Cu), manganese (Mn), titanium (Ti), cobalt (Co), nickel (Ni), and tungsten (W); and a second metal including at least one of a lanthanide metal and an alkaline earth metal
Data Source
AI summary
An organic light-emitting device includes a substrate, an anode on the substrate, a hole transport region on the anode, an emission layer on the hole transport region, an electron transport region on the emission layer, and a cathode on the electron transport region, wherein the electron transport region includes an electron injection layer including a first material including at least one of a halide of an alkali metal, and a second material including at least one of a lanthanide metal and a alkaline earth metal, and wherein the cathode contacts the electron injection layer and includes a first metal including at least one of silver, gold, platinum, copper, manganese, titanium, cobalt, nickel, and tungsten, and a second metal including at least one of a lanthanide metal and an alkaline earth metal, wherein an amount of the first metal is equal to or greater than that of the second metal.