Organometallic Emitter and Amine Capping Layer for OLED Luminescence
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Solution Overview
Problem
Current organic light-emitting devices face challenges in achieving high efficiency and suitable luminescence characteristics, particularly in terms of frontal and lateral luminescence efficiency, due to limitations in the emission layer and capping layer materials.
Innovation Solution
A light-emitting device structure incorporating a first electrode, a second electrode, an interlayer with an emission layer, and a capping layer, where the emission layer includes an organometallic compound represented by Formula 1 and the capping layer includes an amine compound with specific refractive index and energy level conditions, optimizing the luminescence efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional emission layer materials are used, then device structure is simple, but frontal and lateral luminescence efficiency are insufficient
Solution Approach 1:
The emission layer uses a composite system comprising an organometallic compound (Formula 1) as dopant and a host material, where the organometallic compound contains specific ligands (L11-L13) that tune emission properties. This composite approach enables simultaneous achievement of high frontal and lateral luminescence efficiency while maintaining manageable device structure
Solution Approach 2:
The patent optimizes specific parameters including the organometallic compound's HOMO energy level (−4.5 eV or less) and LUMO energy level (−1.0 eV or less), along with the capping layer's refractive index (1.84 or more at 450 nm). These parameter adjustments enhance charge carrier injection and light extraction efficiency, resolving the contradiction between structural simplicity and luminescence performance
2Productivity
If emission layer materials with improved luminescence characteristics are used, then frontal and lateral luminescence efficiency are enhanced, but device complexity increases
Solution Approach 1:
The patent applies local quality by positioning specific functional components in targeted locations: the organometallic compound with tuned HOMO/LUMO levels is placed in the emission layer to optimize charge carrier recombination, while the high refractive index capping layer is positioned at the top to enhance light extraction. This localized optimization achieves high luminescence efficiency without requiring complex structures throughout the entire device
Solution Approach 2:
The capping layer acts as an intermediary between the emission layer and the external environment, with its high refractive index (≥1.84 at 450 nm) serving as a optical mediator that enhances light extraction efficiency. This intermediary layer simplifies the overall device structure by providing a single, optimized component rather than multiple complex layers
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 proposed structure enhances both frontal and lateral luminescence efficiency, achieving excellent luminescence characteristics by leveraging the properties of the organometallic compound and amine compound in the emission and capping layers.
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 the holes and the electrons, recombine in the emission layer to produce excitons. The excitons may transition (i.e., relax) from an excited state to a ground state, thereby generating light.
Implementation Method 2
the amine compound has a refractive index of 1.84 or more with respect to light of 450 nm
Data Source
AI summary
A light-emitting device, an electronic apparatus including the light-emitting device, and a consumer product including the light-emitting device are provided. The light-emitting device includes a first electrode, a second electrode facing the first electrode, an interlayer arranged between the first electrode and the second electrode and including an emission layer, and a capping layer arranged outside the first electrode or outside the second electrode. The emission layer includes a first emitter, the first emitter emits first light having a maximum emission wavelength of 470 nm or less, the first emitter includes platinum (Pt), and the capping layer includes an amine compound.