Light-Emitting Device Capping Layer for Dual-Angle Green Efficiency
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Solution Overview
Problem
Existing light-emitting devices face challenges in achieving both frontal and lateral luminescence efficiency simultaneously, particularly in the green light spectrum, which affects the quality of electronic apparatuses that utilize these devices.
Innovation Solution
Incorporating a capping layer with an amine-containing compound and a platinum-based emitter in the light-emitting device, where the emission peak wavelength is between 520 nm to 550 nm, and the CIEy to reflective index ratio (RCR) is 38 or less, enhances both frontal and lateral luminescence efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional emission layer is used in light-emitting devices, then the device structure is simple, but the device cannot achieve both frontal and lateral luminescence efficiency simultaneously
Solution Approach 1:
The emission layer is segmented into multiple functional sub-layers: a first emission sub-layer containing platinum-based emitter for frontal luminescence, and a second emission sub-layer containing green light-emitting material for lateral luminescence. This segmentation allows each sub-layer to optimize for its specific function, achieving both frontal and lateral luminescence efficiency simultaneously while maintaining a relatively simple overall device structure.
2Illumination intensity
If the emission peak wavelength is optimized for frontal viewing, then frontal luminescence efficiency is improved, but lateral luminescence efficiency deteriorates
Solution Approach 1:
Different regions of the emission layer are assigned different material compositions and emission characteristics. The first emission sub-layer uses platinum-based emitters with specific emission peak wavelengths optimized for frontal viewing, while the second emission sub-layer uses green light-emitting materials optimized for lateral viewing. This local quality differentiation allows the device to achieve optimal performance in both frontal and lateral directions simultaneously.
3Device complexity
If a single emitter material is used, then the device complexity is low, but the viewing angle and luminance characteristics are limited
Solution Approach 1:
The emission layer employs a composite structure with two distinct emitter materials: platinum-based emitters in the first sub-layer and green light-emitting materials in the second sub-layer. This composite material approach enables the device to achieve superior viewing angle and luminance characteristics by combining the advantages of different emitter types, while the layered structure maintains manageable device 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 results in a light-emitting device with improved frontal and lateral luminescence efficiency, enabling the production of high-quality electronic apparatuses with enhanced viewing angles and luminance characteristics.
Implementation Method 1
Holes provided from the first electrode move toward the emission layer through the hole transport region, and electrons provided from the second electrode move toward the emission layer through the electron transport region. Carriers, such as holes and electrons, recombine in the emission layer to produce excitons. These excitons transition from an excited state to a ground state to thereby generate light.
Implementation Method 2
the capping layer includes an amine-containing compound... R(cap) is a refractive index of the amine-containing compound with respect to a second light having a wavelength that is within ±20 nm of the emission peak wavelength of the first light
Data Source
AI summary
Provided is a light-emitting device and an electronic apparatus including the same. 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, wherein 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 along 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 platinum, the capping layer includes an amine-containing compound, and a value of a 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 Equation 1.CIEy/R(cap)×100 Equation 1