Quantum dot fiber gas sensor and preparation method thereof

A gas sensor and quantum dot technology, which is used in instruments, measuring devices, scientific instruments, etc., can solve the problems of low gas sensitivity of optical fiber gas sensors, and is suitable for remote sensing and networking, easy to array, and transmits a large amount of information. Effect

Active Publication Date: 2017-05-10
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Aiming at the above defects or improvement needs of the prior art, the present invention provides a quantum dot optical fiber gas sensor and its preparation method. The problem of low gas sensitivity

Method used

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  • Quantum dot fiber gas sensor and preparation method thereof
  • Quantum dot fiber gas sensor and preparation method thereof
  • Quantum dot fiber gas sensor and preparation method thereof

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Experimental program
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Effect test

Embodiment 1

[0044] The structure of the quantum dot fiber optic gas sensor that embodiment 1 provides is as figure 1 As shown, it includes a fiber optic probe and a gas-sensitive layer; the gas-sensitive layer is coated on the hemispherical end of the fiber-optic probe;

[0045] In Example 1, the optical fiber probe is composed of a single-mode optical fiber and a photonic crystal optical fiber; the fusion site has a fusion bubble with a radius of 10 μm to 30 μm, and inside the PCF, there is a photonic crystal with a length of 100 μm to 300 μm at a distance of 200 μm from the fusion bubble. Optical fiber air hole structure, the end of the optical fiber probe is a hemispherical fusion ball with a radius of 60 μm to 100 μm obtained by melting PCF; the total length of the optical fiber probe (from the fusion bubble to the end) is 400 μm to 700 μm; the fiber probe’s The spectrum is multi-beam interference, which changes with the change of the refractive index at the end of the fiber probe; in...

Embodiment 3

[0056] The optical fiber probe that adopts in embodiment 3, its structure is as Figure 4 As shown; the SMF is fused with the thin optical fiber, the length of the thin optical fiber is controlled to be 300 μm to 500 μm, and the Bragg grating (FBG) is etched on the thin optical fiber; the preparation process is as follows;

[0057] (1) Connect SMF and thin fiber (T-F);

[0058] (2) cutting the thin optical fiber part, and retaining the thin optical fiber with a length of 300 μm to 500 μm;

[0059] (3) Use a femtosecond laser to periodically etch the thin fiber according to the designed FBG parameters;

[0060] The optical fiber probe interference structure prepared by the above method can measure the refractive index change at the end of the FBG central wavelength.

[0061] The preparation method of the quantum dot fiber optic gas sensor provided by the present invention will be described in detail below in conjunction with specific examples.

Embodiment 4

[0062] The preparation method of the quantum dot fiber optic gas sensor provided by embodiment 4 comprises the steps:

[0063] (1) With lead oxide (PbO) as lead source, bistrimethylsilylsulfane (TMS) is as sulfur source, adopts colloid chemical method reaction to prepare PbS colloidal quantum dot solution;

[0064] Specifically, 0.9g (4mmol) PbO was dissolved in 3ml oleic acid (OA) and 17ml octadecene (ODE) under a nitrogen atmosphere and heated to 90°C to prepare the precursor of lead oleate as a lead source; After reaching 8 hours, the temperature of the precursor was raised to 120°C; 180ul (1mmol) TMS was dissolved in 10ml ODE as a sulfur source;

[0065] Inject the sulfur source into the lead source at 120°C. After the color of the reaction system turns black completely (about 15s), put the solution into cold water to quickly lower the temperature to room temperature; add acetone to the cooled solution, and remove it after centrifugal stirring. The supernatant is then dis...

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Abstract

The invention discloses a quantum dot fiber gas sensor and a preparation method thereof. The quantum dot fiber gas sensor comprises a fiber probe and a gas-sensitive layer comprising colloidal quantum dots, a refractive index sensitive area of the fiber probe is uniformly coated with the gas-sensitive layer, carrier concentration changes when the gas-sensitive layer of the fiber probe adsorbs gas, so that gas-sensitive layer refractive index change, optical fields in the fiber probe change, extinction ratio of spectrums change, the spectrums drift, gas concentration is obtained according to variation of the extinction ratio and the spectrums, the quantum dot fiber gas sensor has the advantages that the sensor is high gas-sensitive responsibility, distributed networking is easily achieved. According to the preparation method, the gas-sensitive layer is uniform and excellent in adhesive force and obtained by the aid of a layer-by-layer electrostatic self-assembly method, the thickness of the gas-sensitive layer can be adjusted, doping or surface decoration is achieved by the aid of short-chain ligand solution, adjusting and controlling are achieved according to characteristics of different target gases, and sensitivity and selectivity of the target gases are further improved.

Description

technical field [0001] The invention belongs to the technical field of gas detection and sensing, and more specifically relates to a quantum dot optical fiber gas sensor and a preparation method thereof. Background technique [0002] Gas sensors are widely used in the detection of flammable and explosive gases and toxic and harmful gases. The currently widely used semiconductor resistive gas sensor has the characteristics of simple use and good portability, but it has the disadvantages of high working temperature (usually needs to be heated to 200°C), and the detection accuracy is not high, making it difficult to accurately detect ppb-level low concentrations Gas; on the other hand, semiconductor resistive gas sensors rely heavily on carrier mobility to obtain a faster response, and their electrical response signals are susceptible to electromagnetic interference; and are not suitable for detecting gases dissolved in liquids. [0003] Optical gas sensors based on gas non-di...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/45G01N27/12
CPCG01N21/45G01N27/12G01N2021/458
Inventor 刘欢唐明高峰王阳张鹏张文楷
Owner HUAZHONG UNIV OF SCI & TECH
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