Organic Photoelectric Conversion Element Buffer Layer Dark Current Suppression
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Solution Overview
Problem
Conventional organic photoelectric conversion elements suffer from insufficient suppression of dark currents.
Innovation Solution
A photoelectric conversion element is designed with a buffer layer made of amorphous inorganic material, having an energy level of 7.7 to 8.0 eV and a HOMO energy level difference of 2 eV or more from the organic photoelectric conversion layer, formed with metal oxides like zinc oxide and aluminum oxide, to create a high energy barrier and reduce dark currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional organic photoelectric conversion element structure is used, then the manufacturing process is simpler than inorganic semiconductor elements, but dark current suppression is insufficient
Solution Approach 1:
An inorganic buffer layer is introduced as an intermediary between the organic photoelectric conversion layer and the electrode. This buffer layer serves as a mediator to suppress dark current while maintaining the simplicity of the organic photoelectric conversion element structure and manufacturing process.
Solution Approach 2:
The photoelectric conversion element employs a composite structure combining organic semiconductor materials in the photoelectric conversion layer with inorganic materials in the buffer layer. This composite approach leverages the advantages of both material types to achieve low dark current while preserving manufacturing simplicity.
2Object-generated harmful factors
If the buffer layer energy level is increased to 7.7-8.0 eV with HOMO level difference of 2 eV or more, then dark current suppression is improved, but the device complexity increases
Solution Approach 1:
The buffer layer's energy level parameters are specifically controlled (energy level of 7.7-8.0 eV and HOMO level difference of 2 eV or more) to achieve optimal dark current suppression. By precisely adjusting these energy level parameters, effective dark current suppression is achieved without requiring complex device structural changes.
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 effectively suppresses dark currents and enhances the energy barrier, improving the performance and pressure resistance of the photoelectric conversion element, making it suitable for high-sensitivity imaging and infrared sensors.
Implementation Method 1
a buffer layer disposed in a layer upper than the organic photoelectric conversion layer, the buffer layer including an amorphous inorganic material and having an energy level of 7.7 to 8.0 eV and a difference in a HOMO energy level from the organic photoelectric conversion layer of 2 eV or more
Implementation Method 2
an organic photoelectric conversion layer disposed in a layer upper than the first electrode, the organic photoelectric conversion layer including one or two or more organic semiconductor materials
Data Source
AI summary
To provide an organic photoelectric conversion element, imaging device, and optical sensor having low dark currents, and a method of manufacturing a photoelectric conversion element. Provided is a photoelectric conversion element, including: a first electrode; an organic photoelectric conversion layer disposed in a layer upper than the first electrode, the organic photoelectric conversion layer including one or two or more organic semiconductor materials; a buffer layer disposed in a layer upper than the organic photoelectric conversion layer, the buffer layer including an amorphous inorganic material and having an energy level of 7.7 to 8.0 eV and a difference in a HOMO energy level from the organic photoelectric conversion layer of 2 eV or more; and a second electrode disposed in a layer upper than the buffer layer.