Fullerene Electron Blocking Layer for Thermal Stability in Organic Photoelectric Devices
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Solution Overview
Problem
Conventional organic photoelectric conversion devices suffer from reduced sensitivity and increased dark current when exposed to heat, lacking sufficient heat resistance and high-speed response properties.
Innovation Solution
Incorporating a pair of electrodes with a photoelectric conversion layer sandwiched between them, and at least one electron blocking layer containing fullerene or fullerene derivatives, specifically with a mixed layer configuration that includes a first electron blocking layer with 0-10% fullerene volume ratio and a second layer with an electron donating organic material, enhancing thermal stability and charge transportability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fullerene is used in the electric charge blocking layer to improve electron transport, then electron transport efficiency is improved, but heat resistance deteriorates when exposed to temperatures of 200°C or more
Solution Approach 1:
The patent uses composite materials by combining fullerene (C60) with electron-donating organic materials (such as TPD, TCTA, or mCP) in the electron blocking layer. This composite structure allows the layer to maintain electron transport capabilities while gaining thermal stability from the organic materials that can withstand temperatures of 200°C or more.
Solution Approach 2:
The patent changes the compositional parameters of the electron blocking layer by controlling the mixing ratio of fullerene and electron-donating organic materials. By optimizing these parameters, the layer achieves both sufficient electron transport performance and adequate heat resistance for manufacturing processes.
2Reliability
If mixed layers of electron acceptor and electron donor are used throughout the photoelectric conversion layer to increase photoelectric conversion efficiency, then photoelectric conversion efficiency is improved, but heat resistance deteriorates
Solution Approach 1:
The patent applies local quality by differentiating the composition of different layers. The photoelectric conversion layer uses mixed layers of electron acceptor and donor for high efficiency, while the electron blocking layer uses a specific composite of fullerene and electron-donating materials for heat resistance. Each layer has optimized local composition suitable for its function.
Solution Approach 2:
The patent segments the device into functionally distinct layers with different material compositions. The photoelectric conversion layer is separated from the electron blocking layer, allowing each to be optimized independently - one for efficiency and one for heat resistance.
3Reliability
If conventional organic photoelectric conversion films are used to achieve high photoelectric conversion efficiency and low dark current, then sensitivity is improved, but heat resistance deteriorates when exposed to manufacturing process temperatures
Solution Approach 1:
The patent introduces electron-donating organic materials as intermediary substances in the electron blocking layer. These materials act as mediators that protect the sensitive photoelectric conversion layer from thermal degradation during manufacturing while allowing the device to maintain its sensitivity and photoelectric conversion efficiency.
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 configuration achieves high sensitivity, low dark current, and rapid response properties while maintaining heat resistance, suitable for applications requiring high photoelectric conversion efficiency and stability.
Implementation Method 1
fullerene is used for transporting electrons using a characteristic of an n-type organic semiconductor
Implementation Method 2
a photoelectric conversion layer generating an electric charge by absorbing light
Data Source
Figure 1A~1B
Figure 2
AI summary
A photoelectric conversion device having: a pair of electrodes (11;15); a photoelectric conversion layer (12) sandwiched between the pair of electrodes; and at least one electron blocking layer (16Ab) provided between one electrode of the pair of electrodes and the photoelectric conversion layer, wherein the photoelectric conversion layer contains at least one organic material, and the at least one electron blocking layer has a mixed layer (16Aa) containing fullerene or fullerene derivatives.