Light-Emitting Device Hole Injection Layer Energy Alignment
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Solution Overview
Problem
Existing light-emitting devices often suffer from dark spots, limited lifespan, and high production costs due to complex manufacturing processes.
Innovation Solution
A light-emitting device structure comprising a first electrode, a second electrode, an emission layer, a hole transport layer, a hole injection layer, and an electron transport region, where the hole transport layer and hole injection layer have distinct energy levels and include specific inorganic materials, optimizing the energy level alignment to reduce driving voltage and enhance lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex manufacturing process is used to achieve perfect device performance, then device performance is improved, but production cost increases and manufacturing complexity increases
Solution Approach 1:
The patent combines the hole injection layer and hole transport layer into a single layer structure. This merged layer simultaneously performs hole injection and hole transport functions, eliminating the need for separate layers and simplifying the manufacturing process while maintaining device performance
Solution Approach 2:
The single layer structure serves multiple functions: it acts as both the hole injection layer and hole transport layer. This multi-functional design reduces the number of manufacturing steps and material layers required, thereby reducing production complexity and cost while preserving the necessary device performance
2Reliability
If multiple separate layers are used for hole injection and transport, then device performance is improved, but manufacturing complexity and production cost increase
Solution Approach 1:
The patent merges the hole injection layer and hole transport layer into a single integrated layer. This consolidation reduces the number of manufacturing steps, material deposition processes, and quality control checkpoints, thereby simplifying production while maintaining the functional performance of both hole injection and transport
3Duration of action of moving object
If energy level alignment is optimized between hole injection layer and hole transport layer, then driving voltage is reduced and lifespan is extended, but material selection and process complexity increase
Solution Approach 1:
The patent optimizes the energy levels of the single layer by carefully selecting materials with specific HOMO and LUMO parameters. By adjusting these energy level parameters within the unified layer, the device achieves reduced driving voltage and extended lifespan without requiring multiple separately optimized layers, thus managing material selection 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 proposed design eliminates dark spots, improves lifespan characteristics, and simplifies the production process, thereby reducing costs while maintaining excellent performance.
Implementation Method 1
the hole injection layer and the hole transport layer satisfy the following Equations 1 and 2: |ELUMO_HIL|>|ELUMO_HTL|+0.1 eV Equation 1, |EHOMO_HIL|>|EHOMO_HTL|+0.1 eV Equation 2
Implementation Method 2
When holes provided from the anode and electrons provided from the cathode combine in the emission layer, excitons are produced that may fall from an excited state to the ground state, thereby generating light
Data Source
AI summary
A light-emitting device includes: a first electrode; a hole injection layer; a hole transport layer; an emission layer; an electron transport region; and a second electrode, stacked in order, wherein the hole transport layer and the hole injection layer are different from each other, the hole injection layer includes a first inorganic material, the first inorganic material is an oxide of at least one metal selected from tungsten (W), molybdenum (Mo), zinc (Zn), copper (Cu), nickel (Ni), cobalt (Co), gallium (Ga), and germanium (Ge), the first inorganic material has a work function with an absolute value of about 4.3 eV to about 5.3 eV, and the hole injection layer and the hole transport layer satisfy Equations 1 and 2:|ELUMO_HIL|>|ELUMO_HTL|+0.1 eV Equation 1|EHOMO_HIL|>|EHOMO_HTL|+0.1 eV. Equation 2