OLED Electron Injection Layer Halogen Dipole Materials
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Solution Overview
Problem
Conventional organic light emitting devices face limitations due to high driving voltages, low light emission brightness, low luminance, and short life spans, as well as requiring additional backlights and having limitations in response speed and viewing angle.
Innovation Solution
An organic light emitting diode structure is developed with a first and second electrode, an emission layer, and an electron injection layer containing halogen dipole materials based on transition or post-transition metals and metals with a work function of 4.0 eV or less, along with an electron transport layer and a hole transport layer, enhancing electron injection and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional organic light emitting devices are used, then device structure is simple, but driving voltage is high and lifespan is short
Solution Approach 1:
The electron injection layer uses a composite structure combining a transition metal halide layer (CuI, TlI, AgI, CdI2, HgI2, SnI2, PbI2, BiI3, ZnI2, MnI2, FeI2, CoI2, NiI2, AlI3, ThI4, or UI3) with a low work function metal layer (Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, Yb, or Sm). This composite material approach enables efficient electron injection while stabilizing the device structure, thereby extending lifespan without significantly increasing structural complexity
Solution Approach 2:
The invention optimizes the work function parameter of the electron injection layer by selecting materials with work functions of 4.0 eV or less, and specifically 3.0-3.5 eV for the low work function metal. This parameter optimization enables efficient electron injection at lower driving voltages while improving device stability and lifespan
2Device complexity
If conventional organic light emitting devices are used, then device structure is simple, but luminance and light emission efficiency are low
Solution Approach 1:
The composite electron injection layer with transition metal halide and low work function metal creates optimal conditions for electron-hole recombination in the emission layer, significantly improving light emission efficiency and luminance while maintaining a relatively simple overall device structure
Solution Approach 2:
By optimizing the work function parameter to 3.0-3.5 eV and controlling the thickness of the electron injection layer at 0.1-5 nm, the invention achieves efficient electron injection that enhances carrier balance in the emission layer, thereby improving luminance and light emission efficiency
3Weight of moving object
If LCD is used, then weight and thickness are reduced, but response speed is limited and viewing angle is restricted
Solution Approach 1:
The organic light emitting diode is a self-emitting device that generates its own light through electroluminescence in the emission layer, eliminating the need for external backlights. This self-service capability enables fast response speeds and wide viewing angles while maintaining lightweight and thin form factors
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 an organic light emitting diode with improved efficiency and extended lifespan, overcoming the limitations of conventional devices by providing good element stability and long lifespan while maintaining wide viewing angles and fast response times.
Implementation Method 1
an electron injection layer between the second electrode and the emission layer. The electron injection layer may include a first halogen dipole material based on a transition or post-transition metal, and a second halogen dipole material based on a metal having a work function of 4.0 eV or less
Implementation Method 2
a second halogen dipole material based on a metal having a work function of 4.0 eV or less
Implementation Method 3
The organic light emitting element forms excitons from the combination of electrons injected from one electrode and holes injected from another electrode into the emission layer, and the excitons emit energy in the form of visible light
Data Source
AI summary
An organic light emitting diode according to an example embodiment of the present disclosure includes: a first electrode; a second electrode facing the first electrode; an emission layer between the first electrode and the second electrode; and an electron injection layer between the second electrode and the emission layer. The electron injection layer includes a first halogen dipole material based on a transition or post-transition metal I, and a second halogen dipole material based on a metal having a work function of 4.0 eV or less.