Graphene Vertical OLED Transistors for Low-Voltage AMOLED Backplanes
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Solution Overview
Problem
Current active matrix OLED displays face limitations due to the low mobility and poor stability of amorphous silicon TFT backplanes, leading to high fabrication costs and size constraints, while solution-processible organic semiconductor materials require high source-drain voltages and complex fabrication steps.
Innovation Solution
The development of graphene-enabled vertical organic light emitting transistors (OLETs) and displays, featuring a light emitting layer, capacitor with a dielectric layer, and carbon electrodes, including graphene, graphene oxide, or fluorographene, to reduce voltage requirements and simplify fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If amorphous silicon TFT backplanes are used, then fabrication cost is reduced, but mobility and stability deteriorate
Solution Approach 1:
The patent changes the material parameter from amorphous silicon to carbon-based materials (graphene, carbon nanotubes) which fundamentally alters the electrical properties, achieving both low cost and high performance simultaneously
Solution Approach 2:
The invention uses composite carbon-based materials combining graphene and carbon nanotubes to create a backplane that achieves superior mobility and stability while maintaining fabrication simplicity
2Ease of manufacture
If solution processible organic semiconductor materials are used, then fabrication cost is reduced, but source-drain voltage requirement increases
Solution Approach 1:
The patent changes the semiconductor material from conventional organic semiconductors to carbon-based materials, fundamentally improving charge carrier mobility and reducing the voltage threshold for device operation
Solution Approach 2:
The invention adopts the solution-processable fabrication advantage of organic materials but copies the superior electrical properties of inorganic carbon materials, achieving both low cost and low voltage operation
3Reliability
If poly-Si TFTs are used, then mobility is improved, but fabrication cost and time increase
Solution Approach 1:
The patent changes the material system from polycrystalline silicon to carbon-based materials, achieving comparable or superior mobility through different physical mechanisms while enabling lower temperature, simpler fabrication processes
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 approach enables efficient, low-voltage operation and improved brightness and efficiency of OLEDs by tailoring the work function of graphene electrodes, reducing power dissipation and enhancing the stability and production yield of OLED displays.
Implementation Method 1
tailoring the work function of graphene electrodes
Implementation Method 2
light emitting layer formed of at least one light emitting material
Implementation Method 3
gate tunable carbon electrode
Implementation Method 4
at least one capacitor including a dielectric layer
Data Source
AI summary
Devices, structures, materials and methods for carbon enabled vertical light emitting transistors (VLETs) and light emitting displays (LEDs) are provided. In particular, architectures for vertical polymer light emitting transistors (VPLETs) for active matrix organic light emitting displays (AMOLEDs) and AMOLEDs incorporating such VPLETs are described. Carbon electrodes (such as from graphene) alone or in combination with conjugated light emitting polymers (LEPs) and dielectric materials are utilized in forming organic light emitting transistors (OLETs). Combinations of thin films of ionic gels, LEDs, carbon electrodes and relevant substrates and gates are utilized to construct LETs, including heterojunction VOLETs.