Luminescence Device Capping Layer for Light Extraction
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Solution Overview
Problem
Existing luminescence devices face challenges in maintaining reliability under high-temperature and high-humidity environments and achieving high light-extraction efficiency, particularly due to limitations with organic capping layers.
Innovation Solution
A luminescence device incorporating a capping layer composed of a metal atom and a metal halide compound, such as lanthanide or transition metals combined with alkali metals and halogens, which forms a ternary compound, enhancing reliability and allowing for adjustable refractive indices to improve light-extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an organic capping layer is used, then the device structure is simple and easy to manufacture, but the reliability deteriorates under high-temperature and high-humidity environments
Solution Approach 1:
The patent uses a composite capping layer structure consisting of an inorganic layer (alumina or silica) and an organic layer. The inorganic layer provides high reliability and environmental stability under harsh conditions, while the organic layer maintains ease of manufacture and deposition. This composite structure resolves the contradiction by combining materials with complementary properties.
2Ease of manufacture
If a conventional capping layer is used, then the manufacturing process is simple, but the light-extraction efficiency is insufficient
Solution Approach 1:
The patent changes the refractive index parameter of the capping layer by using inorganic materials (alumina with n≈1.7-1.9 or silica with n≈1.45) instead of conventional organic materials. This parameter change optimizes the optical properties for light extraction while maintaining a simple manufacturing process through atomic layer deposition (ALD) or chemical vapor deposition (CVD) methods.
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 device maintains high reliability under harsh conditions and achieves improved light-extraction efficiency by using an inorganic capping layer with adjustable refractive indices, reducing manufacturing costs and optical efficiency deterioration.
Implementation Method 1
The capping layer may have a refractive index of 1.4-2.0 in a wavelength range of 280-780 nm
Data Source
AI summary
A luminescence device includes a first electrode, a first emission portion disposed on the first electrode, a second electrode disposed on the first emission portion, and a capping layer disposed on the second electrode and including a metal atom and a metal halide compound, wherein the metal atom is a lanthanide metal, a transition metal, or a post-transition metal and the metal halide compound is formed by combining an alkali metal atom and a halogen atom.