Semiconductor resistance-type gas sensor and preparation method thereof

A gas sensor and semiconductor technology, applied in the direction of material resistance, can solve the problems of high working temperature and low sensitivity, and achieve the effect of low cost, high sensitivity and real-time monitoring.

Active Publication Date: 2014-03-26
HUAZHONG UNIV OF SCI & TECH
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  • Description
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Problems solved by technology

Obviously, the operating temperature of th

Method used

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  • Semiconductor resistance-type gas sensor and preparation method thereof
  • Semiconductor resistance-type gas sensor and preparation method thereof

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preparation example Construction

[0024] The preparation method of the semiconductor resistive gas sensor of an embodiment of the present invention comprises the following steps:

[0025] (1) Coating the semiconductor colloidal quantum dot solution on the insulating substrate printed with electrodes to form a uniform film. Specifically, the colloidal quantum dots can be coated on the substrate to form a film at room temperature by means of drop coating, spin coating, soaking and pulling, spray coating, printing, and the like.

[0026] (2) Treat the quantum dot film with a short-chain ligand solution to replace the long-chain oleic acid on the surface of the quantum dot, so that gas molecules can easily enter the quantum dot film.

[0027] (3) Removal of residual short-chain ligands and their by-products.

[0028] (4) Steps (1) to (3) are repeatedly performed to obtain a semiconductor colloidal quantum dot film with a desired thickness, and the preparation of the gas sensor is completed.

[0029] The preparat...

Embodiment 1

[0037] (1) Preparation of PbS colloidal quantum dot solution. PbO is used as the lead source, bistrimethylsilathane (TMS) is used as the sulfur source, and the colloid chemical method is used to generate it.

[0038] Specifically, 0.9 g (4 mmol) PbO was dissolved in 3 ml oleic acid (OA) and 17 ml octadecene (ODE) under nitrogen atmosphere and heated to 90 °C to prepare the precursor of lead oleate as the lead source. After evacuating for 8 hours, the temperature of the precursor was raised to 120°C. Dissolve 180ul (1mmol) TMS into 10ml ODE as sulfur source. Quickly inject the sulfur source into the lead source at 120°C, and after the color of the reaction system turns black (about 15s), put the solution into cold water to quickly drop the temperature to room temperature. Add an appropriate amount of acetone to the cooled solution, centrifuge and stir to remove the supernatant, then disperse with toluene and centrifuge with acetone for multiple cycles until the supernatant is...

Embodiment 2

[0042] The PbS colloidal quantum dot solution prepared in Example 1 is evenly dropped on the PET plastic substrate printed with electrodes, and spin-coated for 15s at a speed of 2500rpm; the sodium nitrite (NaNO 2 ) methanol solution to cover the entire quantum dot film, soak for 45s and dry, repeat twice; wash off residual NaNO with anhydrous methanol 2 Particles and their reaction by-products, soaked for 5s and dried, repeated three times; repeated all the above steps twice to obtain three layers of NaNO 2 The processed lead sulfide quantum dot thin film completed the preparation of the gas sensor.

[0043] The response curve of the gas sensor prepared in Example 2 of the present invention to 50 ppm nitrogen dioxide at room temperature was tested.

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Abstract

The invention discloses a semiconductor resistance-type gas sensor and a preparation method thereof. The preparation method comprises the following steps: (1) coating a colloidal semiconductor quantum dot solution on an insulating substrate printed with electrodes, and forming a uniform film; (2) processing a quantum dot film by using a short-chain ligand solution; (3) removing the residual short-chain ligand and byproducts thereof; (4) repeating steps (1)-(3) for many times to obtain a colloidal semiconductor quantum dot film with a required thickness so as to complete preparation of the gas sensor. In the preparation method, the film can be formed on the insulating substrate directly, and the electrodes are prepared on the final colloidal semiconductor quantum dot film. The gas sensor comprises the insulating substrate, the electrodes and a gas-sensitive layer, wherein the gas-sensitive layer is the colloidal semiconductor quantum dot film. The gas sensor can detect instantaneous or subtle change of gas concentration at room temperature, and is high in response and restoration speed, high in sensitivity, safe and portable; therefore, the gas sensor has a good application prospect.

Description

technical field [0001] The invention belongs to the technical field of gas-sensing materials and components, and more specifically relates to a semiconductor resistive gas sensor using a colloidal quantum dot film as a gas-sensing material and a preparation method thereof. Background technique [0002] Traditional semiconductor resistive gas sensors often use metal oxides (such as SnO 2 , ZnO, TiO 2 etc.) are gas-sensitive materials, which have the characteristics of simple measurement method, high sensitivity, fast response, convenient operation, good portability, and low cost. However, this type of gas sensor must be heated to a higher working temperature (200~ 600 ℃), the power consumption is large, which reduces the portability of the sensor, and also increases the safety hazard, which greatly limits its application. In recent years, using the special activity of nanomaterials to realize room temperature gas sensors is becoming a research hotspot and focus. While makin...

Claims

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Application Information

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IPC IPC(8): G01N27/04
Inventor 刘欢唐江傅邱云李敏周东祥
Owner HUAZHONG UNIV OF SCI & TECH
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