Photoelectric Conversion Layer Energy Level Modification
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Solution Overview
Problem
Silicon photodiodes face sensitivity reduction due to decreased absorption area with smaller pixel sizes, and organic materials, while promising, exhibit unpredictable characteristics making it challenging to control properties for effective photoelectric conversion.
Innovation Solution
A photoelectric conversion device is designed with a first and second electrode and a photoelectric conversion layer comprising a mixture of materials forming a pn junction, where a third material with a high dipole moment modifies the energy level distribution, optimizing absorption in specific wavelength regions and improving charge carrier extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel size is reduced to achieve higher resolution, then measurement precision is improved, but absorption area decreases resulting in sensitivity reduction
Solution Approach 1:
The patent uses a composite photoelectric conversion layer comprising multiple organic materials (first material, second material, and third material with high dipole moment) to achieve both high resolution and high sensitivity. The composite structure allows for optimized light absorption and charge carrier generation even in reduced pixel sizes, preventing sensitivity loss that would normally occur with smaller pixels.
Solution Approach 2:
The patent modifies the energy level distribution by introducing a third material with high dipole moment (≥5.5 Debye) into the photoelectric conversion layer. This parameter change in the molecular structure and energy levels enhances the photoelectric conversion efficiency, allowing small pixels to maintain high sensitivity through improved charge carrier generation and extraction mechanisms.
2Reliability
If organic material is used to replace silicon, then sensitivity and integration are improved, but characteristics become unpredictable making property control difficult
Solution Approach 1:
The patent systematically controls the properties of organic materials by selecting materials with specific parameters: the third material must have a dipole moment of ≥5.5 Debye, and its HOMO energy level must be positioned relative to the first material's HOMO level (deeper or within 0.3 eV shallower). These parameter specifications provide predictable control over photoelectric conversion characteristics despite using organic materials.
Solution Approach 2:
The patent assigns specific functional roles to different materials in the composite layer: the first material forms a pn junction for charge separation, the second material complements the photoelectric conversion, and the third material with high dipole moment specifically modifies energy level distribution. This localized functional assignment enables predictable overall performance from individual material properties.
3Reliability
If remaining charge carriers are reduced, then sensitivity is improved, but charge carrier extraction characteristics must be optimized
Solution Approach 1:
The patent improves charge carrier extraction by introducing the third material with high dipole moment (≥5.5 Debye) that modifies the energy level distribution in the photoelectric conversion layer. This parameter change creates more favorable energy gradients for charge carrier extraction, reducing remaining charge carriers and improving sensitivity without requiring complex external extraction mechanisms.
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 enhances charge carrier extraction and reduces remaining charge carriers, leading to improved sensitivity and performance in photoelectric conversion devices, particularly in high-resolution sensors and electronic devices.
Implementation Method 1
A photoelectric conversion device converts light into an electrical signal using photoelectric effects
Implementation Method 2
The third material is different from the first material and the second material and the third material is configured to modify a distribution of energy levels of the first material or the second material. In some embodiments, a dipole moment of the third material may be greater than or equal to about 5.5 Debye
Data Source
AI summary
Disclosed are a photoelectric conversion device, and a sensor and an electronic device including the same. The photoelectric conversion device may include a first electrode and a second electrode and a photoelectric conversion layer between the first electrode and the second electrode. The photoelectric conversion layer includes a first material and a second material, which form a pn junction, and a third material that is different from the first material and the second material. The third material is configured to modify a distribution of energy levels of the first material or the second material.