Organic Infrared Photodetector Active Layer for Low-Noise NIR-SWIR Detection
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Solution Overview
Problem
Current organic photodetectors (OPDs) face challenges in detecting infrared light due to high dark current and noise, particularly in the near-infrared to shortwave infrared (NIR-SWIR) region, which limits their practical detectivity and compatibility with integrated circuit technologies.
Innovation Solution
Incorporating wide-bandgap insulating polymers within the bulk heterojunction (BHJ) of OPDs to suppress noise current by diluting transport and trapping sites, thereby improving specific detectivity under reverse bias conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If organic photodetectors operate in the NIR-SWIR region, then they can detect infrared light, but dark current and noise increase significantly
Solution Approach 1:
The patent changes the bandgap parameter of the active layer materials by incorporating wide-bandgap insulating polymers (such as polyimide, polyamide, polyester) into the bulk heterojunction. This parameter change reduces thermally generated carriers, thereby suppressing dark current and noise while maintaining infrared detection capability in the NIR-SWIR region
Solution Approach 2:
The patent creates a composite active layer combining organic semiconductors with wide-bandgap insulating polymers in a bulk heterojunction structure. This composite material approach leverages the infrared absorption properties of organic semiconductors while utilizing the noise-suppressing properties of wide-bandgap insulators, achieving both detection capability and low noise performance
2Measurement precision
If reverse bias is applied to enhance detection sensitivity, then signal detection improves, but noise current is amplified
Solution Approach 1:
The patent modifies the electrical parameters of the active layer by incorporating wide-bandgap insulating polymers, which reduce the density of trap states and carrier generation sites. This parameter change allows the device to operate under reverse bias with reduced noise amplification, maintaining detection sensitivity while suppressing noise current by two orders of magnitude
3Ease of manufacture
If conventional organic photodetector structures are used, then manufacturing is simple, but specific detectivity remains low
Solution Approach 1:
The patent develops a composite bulk heterojunction active layer combining organic semiconductors with wide-bandgap insulating polymers that can be processed using solution methods. This composite approach maintains the ease of manufacture through spin-coating and other solution processing techniques while dramatically improving specific detectivity from 10^8 Jones to 10^10 Jones
Solution Approach 2:
The patent optimizes the composition parameters of the bulk heterojunction, specifically the ratio of semiconductor to insulating polymer and the molecular weight of the insulating polymer, to achieve optimal balance between manufacturability and detectivity performance
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 incorporation of wide-bandgap insulating polymers reduces noise current by two orders of magnitude, enhancing specific detectivity from 10^8 Jones to 10^10 Jones in NIR-SWIR OPDs, making them suitable for practical utilization under reverse bias operation.
Implementation Method 1
Incorporating wide-bandgap insulating polymers within the bulk heterojunction (BHJ) of OPDs to suppress noise current by diluting transport and trapping sites
Implementation Method 2
one or more photoactive layers comprising one or more semiconducting materials that comprise a photoactive small molecule, an oligomeric, or polymeric electron donor and an electron acceptor
Data Source
AI summary
The present invention relates to a photodetector and methods for making a photodetector configured for converting light to an electronic signal. The photodetector includes a substrate containing a hole transport component and electron transport component; one or more photoactive layers including one or more semiconducting materials that comprise a photoactive small molecule, oligomeric, or polymeric electron donor and an electron acceptor, wherein the electron donor has a narrow bandgap of less than 1.4 eV; and one or more insulating materials, wherein the one or more semiconducting materials and the one or more insulating materials are present in a weight ratio of 1:0.1 to about 1:100; a cathode in electrical contact with the electron or hole transport component; and an anode in electrical contact with the hole or electron transport component.