Light-Emitting Device Amine-Free Capping Layer Luminescence Efficiency
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Solution Overview
Problem
Current light-emitting devices struggle to achieve concurrent frontal and lateral luminescence efficiency, with existing solutions failing to optimize light extraction and emission spectrum effectively.
Innovation Solution
A light-emitting device design featuring a first electrode, a second electrode, an interlayer with an emission layer, and a capping layer containing an amine-free compound, where the emission layer includes an iridium-based emitter with specific ligands and a capping layer refractive index optimized for enhanced light extraction, achieving a balanced emission spectrum between 520 nm and 550 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional capping layer with amine-containing compounds is used, then the refractive index can be adjusted, but the lateral luminescence efficiency deteriorates due to insufficient light extraction
Solution Approach 1:
The patent changes the chemical composition parameters of the capping layer by using amine-free compounds instead of conventional amine-containing compounds. This parameter change enables simultaneous optimization of both frontal and lateral luminescence efficiency by achieving the desired refractive index while maintaining effective light extraction properties.
Solution Approach 2:
The patent employs composite material design by combining specific amine-free compounds (such as mCP and TCTA) in the capping layer with iridium-based emitters in the emission layer. This composite structure achieves balanced optical properties that improve both frontal extraction and lateral emission characteristics.
2Illumination intensity
If the refractive index of the capping layer is increased to improve light extraction, then frontal luminescence efficiency is improved, but the emission spectrum balance deteriorates
Solution Approach 1:
The patent optimizes the refractive index parameter of the capping layer to a specific range (1.7-1.9) by selecting appropriate amine-free compounds. This parameter optimization achieves improved light extraction while maintaining stable emission spectrum balance in the green region (520-550 nm).
Solution Approach 2:
The patent applies local quality optimization by designing the capping layer with specific compounds (mCP, TCTA) that have tailored optical properties. This localized optimization ensures that the refractive index and emission spectrum characteristics are balanced in the specific region where light extraction occurs.
3Ease of manufacture
If amine-containing compounds are used in the capping layer, then the device structure is simpler, but the concurrent optimization of frontal and lateral luminescence efficiency is not achieved
Solution Approach 1:
The patent changes the material selection parameter from amine-containing to amine-free compounds, which maintains structural simplicity while dramatically improving luminescence efficiency. The amine-free compounds provide the necessary optical properties without requiring complex additional layers or structures.
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 achieves excellent frontal and lateral luminescence efficiency simultaneously, improving the quality of electronic apparatuses by optimizing light extraction and emission spectrum through the use of an iridium-based emitter and amine-free compound in the capping layer.
Implementation Method 1
the emission layer includes an iridium-based emitter with specific ligands... the first emitter emits first light having a first emission spectrum... an emission peak wavelength of the first light is from about 520 nm to about 550 nm
Implementation Method 2
a capping layer... the capping layer is in the path on which the first light travels... a capping layer refractive index optimized for enhanced light extraction... R(cap) is the refractive index of the amine-free compound
Data Source
AI summary
A light-emitting device and an electronic apparatus including the same are provided. The light-emitting device includes a first electrode, a second electrode facing the first electrode, an interlayer between the first electrode and the second electrode and including an emission layer, and a capping layer. The emission layer includes a first emitter, the first emitter emits a first light having a first emission spectrum, the capping layer is in a path on which the first light travels, an emission peak wavelength of the first light is about 520 nm to about 550 nm. The first emitter includes iridium, the capping layer includes an amine-free compound, and the value of ratio of CIEy to reflective index (RCR value) of the first light extracted to the outside through the capping layer is 38 or less, and the RCR value is calculated according to CIEy/R(cap)×100.