Organic Image Sensor Stack for Low-Light Infrared Sensing
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Solution Overview
Problem
Conventional silicon photodiode-based CMOS image sensors have limitations in low illumination sensitivity and infrared absorption, particularly in mobile image sensors, due to their dependence on operating voltage and limited utility in expanding RGB color image sensing regions.
Innovation Solution
A stack-type organic image sensor with a simplified structure, incorporating an infrared absorption and hole transport composite monolayer formed by codepositing a hole transport material and a metal oxide, which enhances infrared absorption and hole transport functions, and an electron transport layer to improve sensitivity under low illumination conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional silicon photodiode-based CMOS image sensor is used, then visible light absorption is achieved, but infrared light absorption and sensitivity in low illumination conditions are limited
Solution Approach 1:
The patent combines visible light absorption layer and infrared light absorption layer into a single stacked structure, where the visible light absorption layer (e.g., silicon photodiode) and infrared absorption layer (e.g., organic photoelectric material) are vertically integrated. This merging enables simultaneous absorption of both visible and infrared wavelengths, expanding the wavelength range while maintaining sensitivity through the complementary absorption characteristics of each layer.
Solution Approach 2:
The patent employs composite material structures including stacked layers of different photoelectric materials (silicon, organic compounds) with distinct absorption characteristics. The composite structure leverages the high visible light absorption of silicon and the infrared absorption capability of organic materials, creating a system that achieves broadspectral response and improved low illumination sensitivity through material composition rather than单一材料.
2Adaptability or versatility
If an infrared absorption layer is added beneath a visible absorption layer, then infrared absorption is reinforced, but device structure complexity increases
Solution Approach 1:
The patent resolves structural complexity by transitioning from horizontal integration to vertical stacking architecture. Instead of placing infrared and visible absorption layers side-by-side in the plane, the invention stacks them in the vertical dimension, with the visible absorption layer on top and the infrared absorption layer beneath. This dimensional change enables functional integration while maintaining a compact footprint and simplifying the overall device structure.
Solution Approach 2:
The stacked structure serves multiple functions simultaneously: the upper visible absorption layer captures visible light, the lower infrared absorption layer captures infrared radiation, and the interface between layers facilitates charge separation and transport. This multi-functional design achieves both visible and infrared sensing capabilities within a unified structure, reducing the need for separate processing channels and simplifying the overall system architecture.
3Adaptability or versatility
If a dual system is driven by visible light at low voltage and by visible light and infrared ray at high voltage, then organic molecule structure properties are utilized, but utility in mobile image sensors is limited
Solution Approach 1:
The patent implements dynamic voltage control where the operating voltage can be adjusted to switch between different sensing modes. At low voltage, the system operates in visible light sensing mode utilizing the visible absorption layer. At higher voltage, the infrared absorption layer is activated, enabling simultaneous visible and infrared sensing. This dynamic operation allows the device to adapt to different application requirements while maintaining compatibility with low-voltage mobile platforms by defaulting to low-power visible mode.
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 organic image sensor increases efficiency by separating and transporting charge carriers effectively, enabling improved performance in low light conditions and expanding the sensing capabilities to include infrared and ultraviolet regions, suitable for applications like night vision and non-destructive inspection.
Implementation Method 1
an infrared absorption and hole transport composite monolayer between the anode and the cathode
Implementation Method 2
The hole transport material may be a material having a highest occupied molecular orbital (HOMO) level that is between a work function of the anode and a work function of the metal oxide
Implementation Method 3
hole transport composite monolayer... including a hole transport material and a metal oxide
Implementation Method 4
an electron transport layer to enhance sensitivity under low illumination
Implementation Method 5
Organic photoelectric devices... enabling efficient absorption of both visible and infrared light at low voltage
Data Source
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AI summary
An IR organic photoelectric device having a simplified device structure may include an anode and a cathode facing each other and an infrared absorption and hole transport composite monolayer between the anode and the cathode. An organic image sensor including the IR organic photoelectric device may include an absorption layer between the infrared absorption and hole transport composite monolayer and the cathode.