Pulsed Laser Deposition of Transparent Conducting Oxide on OLED Layers
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Solution Overview
Problem
Conventional physical vapor deposition methods, such as sputtering and pulsed laser deposition, damage organic electroluminescent layers in OLEDs due to high kinetic energy particles and UV light, leading to reduced transparency and efficiency in producing transparent OLEDs.
Innovation Solution
A method using pulsed laser deposition to control the maximum particle velocity of target material particles, depositing a first layer at a lower velocity to protect the organic material and a second layer at a higher velocity, while maintaining a supersaturated plasma to reduce damage, and adjusting pressure regimes to ensure a 'soft landing' and UV protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical vapor deposition methods (sputtering or pulsed laser deposition) are used to deposit transparent conducting oxide layers, then the conducting layer can be formed, but the high kinetic energy particles damage the organic electroluminescent layer, causing reduced light emission efficiency or complete failure
Solution Approach 1:
The patent segments the deposition process into two distinct stages: a first deposition stage using low kinetic energy particles to form an initial layer without damaging the organic material, and a second deposition stage using higher kinetic energy particles to complete the conducting oxide layer. This segmentation allows each stage to be optimized for its specific purpose, resolving the contradiction between forming a functional conducting layer and protecting the sensitive organic layer.
Solution Approach 2:
The patent applies preliminary action by first depositing a protective initial layer of transparent conducting oxide material at low particle velocity before depositing the remaining layer at higher velocity. This preliminary layer acts as a protective barrier that shields the organic electroluminescent layer from damage by subsequent high-energy particles, enabling the complete deposition process to proceed without compromising the organic material.
2Manufacturing precision
If high kinetic energy particles are used to deposit target material, then the particles can penetrate and adhere to the substrate, but they damage the organic electroluminescent layer through bombardment and penetration
Solution Approach 1:
The patent applies dynamics by varying the kinetic energy of deposited particles during the deposition process. The method dynamically adjusts particle velocity between two distinct regimes: a first regime with lower velocity (below a predetermined threshold) for the initial layer, and a second regime with higher velocity for subsequent layers. This dynamic adjustment allows the deposition process to achieve good adhesion and layer quality while protecting the organic material from excessive damage.
3Quantity of substance
If sputtering deposition is used to create the plasma, then target material particles are released, but the plasma density is low causing particles to arrive as distinct reactive ions with high kinetic energy that damage the electroluminescent layer
Solution Approach 1:
The patent applies parameter changes by modifying the kinetic energy parameter of the deposited particles. By controlling the maximum velocity of particles during the first deposition stage to remain below a predetermined value, the method changes the energy parameter to reduce damage while still achieving adequate deposition. This parameter adjustment resolves the contradiction between maintaining sufficient deposition rate and minimizing harmful effects on the organic layer.
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 method allows for the deposition of transparent conducting oxides like indium tin oxide on organic electroluminescent layers without damage, enabling the production of efficient and transparent OLEDs by minimizing material penetration and UV impact.
Implementation Method 1
creating a vapor plume of target material by pulsed laser deposition; depositing a first layer of target material on the organic electrically functional material, while maintaining the maximum particle velocity of the deposited particles below a preset value
Implementation Method 2
maintaining the maximum particle velocity of the deposited particles below a preset value; ensuring that the maximum velocity of the particles is below a predetermined value, so that the particles only marginally penetrate and/or damage the organic electrically functional material
Data Source
AI summary
The invention relates to a method for depositing a target material onto an organic electrically functional material. The method includes the steps of: providing a substrate with an organic electrically functional material, like an emissive electroluminescent layer; creating a vapor plume of target material by pulsed laser deposition; depositing a first layer of target material on the organic electrically functional material, while maintaining the maximum particle velocity of the deposited particles below a preset value; and depositing a second layer of target material on the first layer of target material, while the maximum particle velocity of the deposited particles is above the preset value. The invention also relates to an intermediate product and to an organic light emitting diode.