Photoelectric Conversion Element Electron Blocking Layer
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Solution Overview
Problem
Conventional photoelectric conversion elements used in imaging devices and photosensors face challenges in achieving high heat resistance and responsiveness, particularly due to increased dark currents and inadequate performance after heat treatment processes.
Innovation Solution
Incorporating a compound represented by Formula (1) in the electron blocking layer, which features three carbazole structures directly bonded with specific aromatic hydrocarbon or heterocyclic groups, enhances heat resistance and responsiveness by facilitating efficient packing and hole transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If an electron blocking layer is introduced to suppress dark currents, then dark current suppression is improved, but heat resistance deteriorates due to increased dark currents after heat treatment
Solution Approach 1:
The patent changes the chemical composition parameters of the electron blocking layer by incorporating specific compounds (compounds 1-4) with distinct molecular structures containing electron-withdrawing groups. This compositional parameter change enables the layer to maintain both dark current suppression capability and heat resistance, as these compounds exhibit stable electrical properties after heat treatment while still blocking electron flow effectively.
Solution Approach 2:
The patent creates a composite electron blocking layer by combining multiple compounds (compounds 1-4) with different functional characteristics. This composite material approach allows the layer to integrate both dark current blocking functionality and heat resistance properties, as each compound contributes different advantageous properties that complement each other in the composite structure.
2Ease of manufacture
If conventional compounds are used in the electron blocking layer, then manufacturing is simplified, but responsiveness deteriorates due to insufficient photoelectric conversion efficiency
Solution Approach 1:
The patent optimizes the molecular structure parameters of the electron blocking layer compounds by selecting compounds with specific structural characteristics (electron-withdrawing groups, aromatic hydrocarbon groups). These parameter optimizations enhance the material's photoelectric conversion efficiency and responsiveness while maintaining compatibility with conventional manufacturing processes, thus improving performance without significantly complicating manufacturing.
3Ease of manufacture
If heat treatment processes are performed during imaging device fabrication, then device assembly is enabled, but photoelectric conversion efficiency deteriorates due to increased dark currents
Solution Approach 1:
The patent applies beforehand cushioning by designing the electron blocking layer with thermally stable compounds (compounds 1-4) that are pre-configured to resist thermal degradation. This prior preparation ensures that when heat treatment processes are subsequently performed during device fabrication, the electron blocking layer maintains its electrical properties and continues to suppress dark currents effectively, thereby preserving photoelectric conversion efficiency throughout the manufacturing process.
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 use of the specified compound in the electron blocking layer results in improved heat resistance and responsiveness, as demonstrated by reduced dark currents and faster signal intensity rise times, outperforming comparative examples without this compound.
Implementation Method 1
an electron blocking layer is introduced into a photoelectric conversion element used in a photosensor or a solid-state imaging device
Implementation Method 2
the use of a compound represented by Formula (1), which will be described later, in an electron blocking layer results in excellent heat resistance and responsiveness
Implementation Method 3
A photoelectric conversion element comprising: a transparent conductive film; a conductive film; and a photoelectric conversion film and an electron blocking layer which are disposed between the transparent conductive film and the conductive film
Data Source
AI summary
An object of the present invention is to provide a photoelectric conversion element which exhibits excellent heat resistance and responsiveness, and a photosensor and an imaging device which include the photoelectric conversion element. The photoelectric conversion element of the present invention includes: a transparent conductive film; a conductive film; and a photoelectric conversion film and an electron blocking layer which are disposed between the transparent conductive film and the conductive film, wherein the electron blocking layer contains a compound represented by the following Formula (1).