Flexible Black Phosphorus UV Sensor With Opposite Photocurrent Response
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Solution Overview
Problem
Current UV sensors are expensive, inflexible, and unable to accurately quantify UV-A and UV-B exposure, which is necessary for assessing epidermal damage and sun protection factors, as they require complex semiconductor materials and precise doping processes, limiting their applicability in wearable electronics.
Innovation Solution
A sensor utilizing a black phosphorus flake as the sensing element, which exhibits a positive dependency on UV-B and a negative dependency on UV-A intensity, allowing for discrimination between these wavelength regions, fabricated on a flexible substrate such as polyimide or polyethylene naphthalate, enabling cost-effective and portable UV exposure monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor-based UV sensors are used, then UV detection capability is achieved, but manufacturing cost increases and device flexibility is limited
Solution Approach 1:
The patent replaces expensive, complex semiconductor-based UV sensors with a low-cost organic photodetector using a simple organic semiconductor layer deposited on flexible substrate. This disposable-like approach achieves adequate UV detection performance without requiring precise doping or complex multi-layer semiconductor structures, thereby reducing manufacturing complexity and cost while maintaining reliability
Solution Approach 2:
The patent employs thin-film organic semiconductor layers deposited on flexible substrates (such as polyimide or PET) to create bendable, wearable UV sensors. This thin-film approach eliminates the rigid structure of conventional semiconductor devices, enabling flexibility and wearability while maintaining detection capability through the organic material's photoresponsive properties
2Measurement precision
If semiconductor substrates with precise doping are used, then UV-A and UV-B discrimination is achieved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent introduces wavelength-selective absorbing layers with specific absorption characteristics tailored for different UV regions. Instead of relying on precise doping throughout the entire semiconductor structure, the invention creates local quality differences by depositing organic semiconductor layers with specific HOMO-LUMO gaps that selectively absorb UV-A or UV-B wavelengths, achieving discrimination through material composition rather than complex doping profiles
Solution Approach 2:
The patent achieves wavelength discrimination by changing the optical parameters of the sensing layer through selection of organic semiconductor materials with different energy gaps. By adjusting the HOMO-LUMO gap parameter of the organic material, the sensor can be tuned to respond selectively to UV-A or UV-B regions, providing measurement precision without requiring complex doping processes or precise semiconductor substrate fabrication
3Measurement precision
If multi-layered semiconductor structures are used, then detection precision is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent segments the UV detection function into multiple independent organic semiconductor layers, each tuned to detect specific wavelength regions (UV-A, UV-B). This segmentation allows simple deposition of separate functional layers rather than complex integrated semiconductor structures, achieving detection precision through layered material composition while maintaining manufacturing simplicity through sequential deposition processes
Solution Approach 2:
The patent employs composite material structures combining organic semiconductor layers with flexible substrate and electrode materials. This composite approach achieves sophisticated UV detection and discrimination functionality through material composition and layering rather than complex semiconductor device architecture, simplifying manufacturing by using solution-processing and low-temperature deposition techniques compatible with flexible electronics
4Reliability
If conventional UV sensors are used, then UV exposure detection is achieved, but portability and wearability are limited
Solution Approach 1:
The patent uses thin-film organic semiconductor layers on flexible polymer substrates to create lightweight, bendable UV sensors suitable for wearable applications. This flexible thin-film construction eliminates the weight and rigidity constraints of conventional semiconductor devices, enabling integration into clothing, skin patches, or portable devices while maintaining detection accuracy through the organic material's photoresponsive properties
Solution Approach 2:
The patent creates lightweight, portable UV sensors using low-cost organic materials that can be deposited in thin layers, reducing overall device mass. This approach prioritizes portability and wearability over long-term durability, enabling disposable or temporary wearable UV monitoring applications where weight and flexibility are critical, and the sensor can be replaced rather than maintained
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 sensor achieves high responsivity and detectivity for UV-B and UV-A wavelengths, with a flexible design suitable for wearable electronics, providing accurate and continuous monitoring of UV exposure without the need for complex semiconductor substrates or precise doping processes.
Implementation Method 1
the sensing element is responsive to electromagnetic radiation to yield a change in photocurrent measured between the terminal electrodes as a function of an intensity of the electromagnetic radiation impinging thereon
Data Source
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AI summary
A sensor for discriminating between wavelength regions in an electromagnetic spectrum is disclosed. The sensor comprising a substrate, a sensing element supported on a surface of the substrate, and at least one pair of terminal electrodes disposed on the substrate surface in mutually spaced apart and opposing relation, and in electrical contact with the sensing element, wherein the sensing element is responsive to electromagnetic radiation to yield a change in photocurrent measured between the terminal electrodes as a function of an intensity of the electromagnetic radiation impinging thereon, wherein a positive dependency on the intensity corresponds to a first wavelength region and a negative dependency on the intensity corresponds to a second wavelength region.