Organic Light Emitting Device with N-Type Interlayer
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Solution Overview
Problem
Organic light emitting devices face challenges with unstable interfaces between metal electrodes and organic compound layers, leading to increased driving voltage and reduced performance due to energy barriers for hole injection, which limits material selection for hole injection layers and affects charge transport efficiency.
Innovation Solution
An organic light emitting device is designed with a first electrode featuring a conductive layer and an n-type organic compound layer, forming an NP junction with a p-type organic compound layer to reduce energy barriers for hole injection, and additional organic compound layers are n-doped with inorganic materials to enhance charge transport efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electron/hole injection layer or transport layer is added to improve device performance, then the interface stability improves, but the driving voltage increases due to energy level differences
Solution Approach 1:
An n-type organic compound layer is introduced as an intermediary between the metal electrode and the p-type organic compound layer. This intermediary layer facilitates charge injection by forming an NP junction that reduces the energy barrier, allowing efficient charge transport without requiring high driving voltage. The n-type layer acts as a mediator that bridges the energy level mismatch between the metal electrode and the organic compound layers.
Solution Approach 2:
The energy level parameters of the electrode interface are modified by introducing the n-type organic compound layer with specific LUMO and HOMO energy levels. The LUMO level of the n-type layer is positioned to create a favorable energy gradient for electron injection, while the HOMO level forms an NP junction with the p-type layer, effectively changing the energy landscape to reduce injection barriers and driving voltage.
2Productivity
If the Fermi energy level of the anode is adjusted to match the HOMO level of the hole injection layer, then hole injection efficiency improves, but material selection becomes limited
Solution Approach 1:
Instead of adjusting the anode's Fermi energy level to match the HOMO level of the hole injection layer (conventional approach), the invention inverts the approach by introducing an n-type organic compound layer that actively modifies the energy level alignment. The n-type layer's LUMO and HOMO levels are positioned to create favorable energy gradients, allowing the use of conventional anode materials without requiring precise Fermi level matching, thus expanding material selection flexibility while maintaining high hole injection efficiency.
3Reliability
If doping is applied to organic compound layers to improve charge transport, then conductivity increases, but the manufacturing complexity increases
Solution Approach 1:
Doping is applied to the organic compound layers to modify their electrical parameters, specifically increasing charge carrier concentration and conductivity. By controlling the doping level and type (n-type or p-type), the charge transport efficiency is significantly improved. The doping process integrates into the existing manufacturing workflow, allowing for precise control of electrical properties without requiring fundamentally new manufacturing techniques.
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 device with reduced energy barriers for hole injection, improved charge transport, and high luminance at low driving voltage, simplifying the manufacturing process and allowing for efficient hole and electron transport to the light emitting region.
Implementation Method 1
an n-type organic compound layer is formed in a hole injection electrode, and at least one layer of organic compound layers is n-doped or p-doped with an organic or inorganic material
Implementation Method 2
at least one layer of organic compound layers is n-doped or p-doped with an organic or inorganic material
Implementation Method 3
n-doped or p-doped with an organic or inorganic material
Implementation Method 4
electrons and holes are injected into the organic compound layer from the two electrodes, and a current is converted into visible light
Data Source
Figure 1(a)~2
Figure 3~4
Figure 5~6
AI summary
Disclosed is an organic light emitting device and a method for manufacturing the same. The organic light emitting device includes a first electrode, one or more organic compound layers, and a second electrode. The first electrode includes a conductive layer and an n-type organic compound layer disposed on the conductive layer. A difference in energy between an LUMO energy level of the n-type organic compound layer of the first electrode and a Fermi energy level of the conductive layer of the first electrode is 4 eV or less. One of the organic compound layers interposed between the n-type organic compound layer of the first electrode and the second electrode is a p-type organic compound layer forming an NP junction along with the n-type organic compound layer of the first electrode. A difference in energy between the LUMO energy level of the n-type organic compound layer of the first electrode and an HOMO energy level of the p-type organic compound layer is 1 eV or less. One or more layers interposed between the conductive layer of the first electrode and the second electrode is n-doped or p-doped with an organic material or an inorganic material.