Electroluminescent Device Nanoparticle Electron Transport Layer
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Solution Overview
Problem
Existing electroluminescent devices face challenges in preventing leakage current and achieving charge carrier balance, which affects the luminous efficiency of quantum dot emission layers.
Innovation Solution
An electroluminescent device structure is developed with a hole transport layer, an emission layer containing light emitting particles, an electron transport layer featuring nanoparticles with an inorganic oxide core, an organic ligand, and a metal-organic compound chemically bound to the core, and a second electrode, where the LUMO energy level difference between the emission and electron transport layers is optimized to enhance electron transport capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electron transport layer with conventional materials is used, then the device structure is simple, but leakage current occurs and charge carrier balance is poor
Solution Approach 1:
The electron transport layer uses composite nanoparticles comprising an inorganic oxide core (such as ZnO) coated with an organic ligand shell. This composite structure combines the high electron mobility of inorganic materials with the tunable energy levels of organic materials, preventing leakage current while maintaining device simplicity
Solution Approach 2:
The patent adjusts the LUMO energy level of the electron transport layer by selecting specific organic ligands with appropriate energy levels. By changing the ligand parameters (energy level, molecular structure), the charge carrier balance is optimized without significantly increasing device complexity
2Manufacturing precision
If quantum dots with optimized size are used, then light emission wavelength is controlled, but charge carrier balance deteriorates
Solution Approach 1:
The organic ligand on the quantum dot surface acts as an intermediary that mediates charge transfer between the quantum dot and the electron transport layer. By selecting ligands with appropriate HOMO and LUMO energy levels, charge carrier balance is maintained while preserving the wavelength control achieved through quantum dot size optimization
Solution Approach 2:
The patent changes the energy level parameters of the ligand shell to match the electron transport layer, creating favorable energy level alignment. This allows quantum dots of various sizes (different emission wavelengths) to maintain good charge carrier balance through ligand engineering
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
This configuration improves luminous efficiency by preventing leakage current and balancing charge carriers, resulting in enhanced device characteristics and photoluminescence performance.
Implementation Method 1
an electron transport layer disposed on the emission layer and including nanoparticles having electron transport capability
Implementation Method 2
a metal-organic compound chemically bound to the surface of the inorganic oxide core
Implementation Method 3
an organic ligand attached to a surface of the inorganic oxide core
Implementation Method 4
Quantum dots emit light while the excited electrons are transitioned from a conduction band to a valance band
Data Source
AI summary
An electroluminescent device, a method of manufacturing the same, and a display device including the same.The electroluminescent device includes a first electrode, a hole transport layer disposed on the first electrode, an emission layer disposed on the hole transport layer and including light emitting particles, an electron transport layer disposed on the emission layer and including nanoparticles having electron transport capability, and a second electrode disposed on the electron transport layer, wherein at least a portion of the nanoparticles having electron transport capability include an inorganic oxide core represented by Chemical Formula 1, an organic ligand attached to a surface of the inorganic oxide core, and a metal-organic compound chemically bound to the surface of the inorganic oxide core.MxOy Chemical Formula 1