Pb5s2i6 nanowire self-assembled film, preparation method thereof and application thereof in two-factor fire alarm
By preparing a self-assembled Pb5S2I6 nanowire film and applying it to an optoelectronic sensor, fire detection is achieved by combining gas and smoke factors, thus solving the problem of high false alarm rate in traditional fire alarms and realizing highly accurate fire early warning.
Patent Information
- Application Number
- CN202210074675.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-01-21
- Publication Date
- 2025-11-04
- Estimated Expiration
- 2042-01-21
AI Technical Summary
Traditional fire alarms are susceptible to interference from environmental factors, have a high false alarm rate, and lack accuracy in single-factor fire detection. Existing semiconductor metal oxide materials have high operating temperatures and low selectivity.
A self-assembled Pb5S2I6 nanowire film was prepared and applied to a photoelectric sensor. Fire was detected by combining gas and smoke factors through a logic gate analog circuit. The photoelectric response characteristics of Pb5S2I6 nanowires were used to realize dual-mode fire early warning.
It improves the accuracy of fire alarms by identifying fires based on both gas and smoke factors, reducing false alarm rates and enhancing the precision of fire early warning.
Smart Images
Figure CN116524671B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the field of photoelectric thin films, and particularly relates to a Pb5S2I6 nanowire self-assembled film, a preparation method thereof and application thereof in a double-factor fire alarm. BACKGROUND
[0002] Fire is one of the most frequent and common disasters that endanger public safety and social development. The number of deaths caused by fire each year is 20 times the total number of deaths caused by hurricanes, tornadoes, floods and earthquakes. The occurrence of fire is usually accompanied by the generation of harmful gases, smoke particles or high temperatures, and a fire alarm is made according to the changes in these factors. However, the traditional alarm only detects one of these factors, and these factors are easily disturbed by environmental factors and misreported, such as cigarette smoke, water vapor, dust, etc. Frequent false alarms can reduce public confidence and waste public resources. The accurate detection of fire by a single-factor fire alarm remains a great challenge.
[0003] Gas and light are the two main substances generated in the early stage of fire, and accurate detection of these two factors can greatly improve the accuracy of fire warning. Semiconductor metal oxides have excellent optical and electrical properties. However, as the most important and most widely used gas sensor material, these materials have the disadvantages of high working temperature and low selectivity. The methods reported in the literature usually use ultraviolet or visible light to enhance the gas sensing performance. In this case, light can only assist gas sensing and cannot function independently. SUMMARY
[0004] The application provides a preparation method of a Pb5S2I6 nanowire self-assembled film, comprising the following steps:
[0005] Lead iodide, guanidinium isothiocyanate and methanol are mixed, a clean substrate is placed in the mixed system, and ultrasonic is performed. After the ultrasonic is completed, the mixed system with the substrate is packaged in a sealed reactor for solvothermal reaction to prepare the Pb5S2I6 nanowire self-assembled film.
[0006] According to an embodiment of the application, the molar volume ratio of the lead iodide, guanidinium isothiocyanate and methanol is 1 mmol:(1.2-2) mmol:(120-200) mL, for example, 39 mmol:65 mmol:6000 mL.
[0007] According to an embodiment of the application, the material of the substrate is alumina.
[0008] According to an embodiment of the application, the ultrasonic time is 3-10 minutes, for example, 5 minutes.
[0009] According to an embodiment of the application, the temperature of the solvothermal reaction is 110-130℃, for example, 120℃.
[0010] According to an embodiment of the present application, the time of the solvothermal reaction is 10-40h, for example 20-30h, such as 24h.
[0011] According to an embodiment of the present application, after the solvothermal reaction is completed, the system is naturally cooled to room temperature.
[0012] According to a preferred embodiment of the present application, the method for preparing the Pb5S2I6 nanowire self-assembled film comprises the following steps:
[0013] Lead iodide is added to a glass bottle containing methanol, and guanidinium isothiocyanate is added dropwise; the cleaned substrate is loaded into the glass bottle, ultrasonic treatment is performed for 5 minutes, then the system is packaged in a 25mL polytetrafluoroethylene reactor, and reaction is performed at 120℃ for 24h, and the system is naturally cooled to room temperature to obtain a Pb5S2I6 nanowire self-assembled film.
[0014] The present application also provides a Pb5S2I6 nanowire self-assembled film, which is preferably prepared by the above method.
[0015] According to an embodiment of the present application, the Pb5S2I6 nanowire self-assembled film is formed by Pb5S2I6 nanowires with an average diameter of 70-150 nm (for example 100nm).
[0016] According to an embodiment of the present application, the Pb5S2I6 nanowire self-assembled film has photoelectric properties.
[0017] According to an embodiment of the present application, in terms of photoelectric response, the Pb5S2I6 nanowire self-assembled film has a wide detection spectrum range, and the photocurrent is obviously improved within the light illumination range of 250-1500nm wavelength.
[0018] According to an embodiment of the present application, the Pb5S2I6 nanowire self-assembled film has a high on-off ratio (10 3 ) and a fast response recovery speed (1.6 / 1.25s).
[0019] The present application also provides the use of the above-mentioned Pb5S2I6 nanowire self-assembled film in a photoelectric gas sensor.
[0020] The present application also provides a photoelectric gas sensor comprising the above-mentioned Pb5S2I6 nanowire self-assembled film.
[0021] The present application also provides the use of the above-mentioned Pb5S2I6 nanowire self-assembled film or photoelectric gas sensor in a dual-mode fire alarm.
[0022] According to an embodiment of the present application, the method for dual-mode fire alarm comprises:
[0023] I: In the absence of fire, that is, in the normal state, the current is at a low level;
[0024] II: After detecting the gas, the current rises, and then it is necessary to further judge the occurrence of fire by whether there is smoke production; by using the reflection ability of smoke on light, if there is no smoke production, the current change is caused by environmental interference, and under light, there is no reflection of smoke, so it will not cause further change of the current, and it is judged as a non-true fire signal;
[0025] III: When there is fire smoke, the current further rises due to reflected light, and after exceeding the set fire warning line, fire alarm will be caused.
[0026] The application also provides a dual-mode fire warning device containing the Pb5S2I6 nanowire self-assembled film or the photoelectric gas sensor.
[0027] Advantages of the application
[0028] The application synthesizes a Pb5S2I6 nanowire self-assembled film, and makes the self-assembled film into a photoelectric gas sensor device. Through a logic gate simulation circuit, on the basis of gas sensing in a fire, the signal of smoke in a fire is further judged through the photoelectric response characteristics of the sensor device containing the self-assembled film. That is, the method needs both gas and smoke to cause fire warning, which greatly improves the accuracy of the alarm. Compared with the single factor detection in the prior art which is easy to cause false alarm, the application of the Pb5S2I6 nanowire self-assembled film / photoelectric gas sensor device can judge the occurrence of fire by both gas and smoke, and is more accurate. BRIEF DESCRIPTION OF DRAWINGS
[0029] Figure 1 SEM image of the Pb5S2I6 nanowire self-assembled film prepared in Example 1.
[0030] Figure 2 Photoelectric response graph of the Pb5S2I6 nanowire self-assembled film prepared in Example 1.
[0031] Figure 3 Structure schematic diagram of the sensing test device in Example 2.
[0032] The figure legend: 1-air steel cylinder, 2-standard gas steel cylinder, 3-flow meter, 4-cavity, 5-photoelectric gas sensor containing Pb5S2I6 nanowire self-assembled film, 6-Keithley 2602B, 7-computer.
[0033] Figure 4 Dual-mode fire warning method and current change. DETAILED DESCRIPTION
[0034] The technical solutions of the present application will be further described in detail below in combination with specific examples. It should be understood that the following examples are only illustratively described and explained, and should not be interpreted as limiting the scope of protection of the present application. Any technology achieved based on the above description of the present application is covered within the scope of protection intended by the present application.
[0035] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.
[0036] Example 1
[0037] Lead iodide (0.018 g) was added to a glass bottle containing 6 mL of methanol solvent, and 7 μL of guanidinium isothiocyanate was added dropwise. The cleaned substrate was loaded into the bottle, ultrasonicated for 5 minutes, and then packaged in a 25 mL polytetrafluoroethylene reactor. By reacting at 120°C for 24 h, and naturally cooling to room temperature, a Pb5S2I6 nanowire self-assembled film was obtained.
[0038] As shown in Figure 1 , the average diameter of the Pb5S2I6 nanowires in the Pb5S2I6 nanowire self-assembled film is 100 nm.
[0039] As shown in Figure 2 , in terms of photoelectric response, the Pb5S2I6 nanowire self-assembled film has a wide detection spectral range, and has obvious photocurrent improvement within the light illumination range of 250-1500 nm wavelength. At the same time, it also has a high on-off ratio (10 3 ), and a fast response recovery speed (1.6 / 1.25 s).
[0040] Example 2
[0041] The Pb5S2I6 nanowire self-assembled film prepared in Example 1 was made into a photoelectric gas sensor, which was used to assemble a sensing test device as shown in Figure 3 , which is used for dual-mode fire warning. As shown in Figure 4 (a) and (b),
[0042] I: When there is no fire, that is, in the normal state (also known as the safe state), the current is at a relatively low level;
[0043] II: After detecting the gas, the current rises. Next, it is necessary to further judge the occurrence of fire by whether there is smoke. Based on the reflection ability of smoke to light. If there is no smoke, that is, the change in current is caused by environmental interference, then after adding light, there will be no further change in current because there is no reflection of smoke. That is, it is not a real fire signal at this time;
[0044] III: When there is fire smoke, the current caused by the reflected light further rises, and after exceeding the set fire warning line, fire alarm is caused.
[0045] Therefore, by the photoelectric response characteristics under different conditions, the signal of the smoke in the fire can be judged, and the accuracy of the fire alarm is greatly improved.
[0046] The above describes the embodiments of the present application. However, the present application is not limited to the above-described embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A self-assembled Pb5S2I6 nanowire film, characterized in that, The Pb5S2I6 nanowire self-assembled film is formed by the self-assembly of Pb5S2I6 nanowires with an average diameter of 70-150 nm, and is prepared by a method comprising the following steps: Lead iodide, guanidine isothiocyanate and methanol were mixed, a clean substrate was placed in the mixture, and the mixture was sonicated. After sonication, the mixture with the substrate was encapsulated in a closed reactor for solvothermal reaction to prepare the Pb5S2I6 nanowire self-assembled film. The molar volume ratio of lead iodide, guanidine isothiocyanate and methanol is 1 mmol:(1.2-2) mmol:(120-200) mL; The substrate is made of aluminum oxide; The temperature of the solvothermal reaction is 110-130℃, and the time of the solvothermal reaction is 10-40h.
2. The Pb5S2I6 nanowire self-assembled film according to claim 1, characterized in that, The Pb5S2I6 nanowire self-assembled film was prepared by a method comprising the following steps: Lead iodide was added to a glass bottle containing methanol, and guanidine isothiocyanate was added dropwise. The cleaned substrate was placed into the glass bottle, sonicated for 5 minutes, and then the system was encapsulated in a 25 mL polytetrafluoroethylene reactor. The reaction was carried out at 120 °C for 24 h and then naturally cooled to room temperature to obtain a Pb5S2I6 nanowire self-assembled film.
3. The Pb5S2I6 nanowire self-assembled film according to claim 1 or 2, characterized in that, The Pb5S2I6 nanowire self-assembled film has photoelectric properties; The Pb5S2I6 nanowire self-assembled film has a wide detection spectral range, with a significant increase in photocurrent in the light irradiation range of 250–1500 nm. The Pb5S2I6 nanowire self-assembled film has a high on / off ratio (10). 3 It also features fast response and recovery speed (1.6 / 1.25s).
4. The application of the Pb5S2I6 nanowire self-assembled film according to any one of claims 1-3 in photoelectric sensors.
5. A photoelectric sensor, characterized in that, It includes the Pb5S2I6 nanowire self-assembled film according to any one of claims 1-3.
6. The application of the Pb5S2I6 nanowire self-assembled film according to any one of claims 1-3 or the photoelectric sensor according to claim 5 in a dual-mode fire early warning device, wherein the dual-mode fire early warning is a fire early warning caused by both gas and smoke factors.
7. A dual-mode fire early warning device, characterized in that, The device contains a Pb5S2I6 nanowire self-assembled film as described in any one of claims 1-3 or a photoelectric sensor as described in claim 5, wherein the dual-mode fire warning is a fire warning caused by both gas and smoke factors.