TWI675197B - Gas-sensing apparatus - Google Patents

Abstract

A gas sensing device includes a gas sensing device and a light-emitting member spaced from the gas sensing device. The gas sensing device includes a light and gas sensing element for interacting with a gas to be measured and includes an organic semiconductor material, a first electrode connected to the light and gas sensing element, and a distance from the first electrode. The second electrode of the light and gas sensor is connected. The light-emitting element is used to provide light that is irradiated toward the light and gas sensing element and can be absorbed by the light and gas sensing element after the light and gas sensing element interacts with the gas to be measured.

Description

Gas sensing equipment

The invention relates to a sensing device, in particular to a gas sensing device.

In the conventional gas sensors, after gas is sensed by a gas sensing film formed of an inorganic semiconductor material, nitrogen, air, heating (such as infrared light), and the like are used to restore the current value generated after sensing to before sensing Current value for the next sensing. However, this method has (1) the response time is too long; (2) when the response time is not enough, it will cause the current signal generated after the next sensing to be reduced and not obvious, or the variation of the current signal will be used with the use The number of times increases, so that the repeatability is poor or can no longer be used.

Nano letters , 2003, vol. 3, NO. 7, 929-933 disclose a gas sensor capable of sensing gas or organic volatiles at room temperature, and using a carbon nanotube as a sensing film. The gas sensor can use UV light to promote the desorption of the gas, so that the current value generated after the sensing is restored to the current value before the sensing, thereby reducing the recovery time.

An article entitled "Single Zinc Oxide Nanowire Nitric Oxide Gas Sensor Production and Adsorption Kinetics, Zheng Yizheng, National Tsinghua University" revealed a gas sensor that can sense gases at room temperature, and A zinc oxide nanowire was used as a sensing film. The gas sensor can use a fluorescent lamp to illuminate the sensing film, so that the current value generated after the sensing is restored to the current value before the sensing, and compared with UV light, it is convenient and quick to return.

US Patent Publication No. 5448906 discloses a gas sensor capable of sensing a gas at room temperature. The gas sensor includes a polycrystalline semiconductor oxide film for a gas to be measured, two electrodes connected to the polycrystalline semiconductor oxide film and located on the left and right sides of the polycrystalline semiconductor oxide film, respectively, and a A UV lamp located above the polycrystalline semiconductor oxide film. The light source provided by the UV lamp can be absorbed by the polycrystalline semiconductor oxide film, and the adsorbed gas to be measured can be photodesorption on the polycrystalline semiconductor oxide film.

Although the above-mentioned gas sensor can remove the gas to be measured from the inorganic semiconductor film through a fluorescent lamp and a UV lamp, so that the current value generated after the sensing returns to the current value before the sensing, but the recovery time is still too long, and During the recovery process, the current value changes slowly.

Therefore, an object of the present invention is to provide a gas sensing device having a short current recovery time.

Therefore, the gas sensing device of the present invention includes a gas sensing device and a light-emitting member disposed at a distance from the gas sensing device. The gas sensing device includes a light and gas sensing element for interacting with a gas to be measured and includes an organic semiconductor material, a first electrode connected to the light and gas sensing element, and a distance from the first electrode. The second electrode of the light and gas sensor is connected. The light-emitting element is used to provide light that is radiated toward the light and gas sensing element and can be absorbed by the light and gas sensing element.

The effect of the present invention is that through the combination of the light-emitting element and the light and gas sensing element, the light-emitting element is turned on after sensing. During the recovery process, since the light and gas sensing element can absorb light, The optical signal writes the current signal, and at the same time, the light can also promote the desorption of the gas to be measured, so that the current value generated after sensing can be quickly recovered and restored to the current value before sensing, and then the recovery efficiency is improved to perform the following Once sensing. Therefore, the gas sensing device of the present invention has a short current recovery time.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are represented by the same numbers.

Referring to FIG. 1 and FIG. 2, a first embodiment of the gas sensing device of the present invention is installed in a transparent glass container 3 filled with nitrogen or air, and includes a sensing device 1 and a light-emitting element 2. The volume of the glass container 3 is 30 mm ³ and includes an air inlet 31 for the gas to be measured to enter, and an air outlet 32 provided opposite to the air inlet 31. The test gas is, for example, but not limited to, an oxidizing gas or a reducing gas. The gas to be measured is, for example, but not limited to, ammonia, acetone, nitric oxide, or nitrogen dioxide.

The gas sensing device 1 includes a first electrode layer 11, a second electrode layer 12 disposed at a distance from the first electrode layer 11, and a first electrode layer 11 and a second electrode layer 12 which are located between and connected to each other. The light and gas sensor 13 of the first electrode layer 11 and the second electrode layer 12.

The first electrode layer 11 has two oppositely disposed surfaces 111 and a plurality of through holes 10 penetrating through the surfaces 111 and used to expose the light and gas sensor 13. The material of the first electrode layer 11 is, for example, but not limited to, a metal, a metal compound, or a conductive organic material. The metal is, for example, but not limited to, aluminum, gold, silver, calcium, nickel, or chromium. The metal compound is, for example, but not limited to, zinc oxide, molybdenum oxide, or lithium fluoride. The conductive organic material is, for example, but not limited to, polydioxyethylthiophene-polystyrenesulfonic acid. The thickness of the first electrode layer 11 ranges from 0.01 μm to 1 μm. The size of the through holes 10 ranges from 10 nm to 1000 nm. In the first embodiment, the first electrode layer 11 is made of aluminum and has a thickness of 60 nm, and the sizes of the through holes 10 are 200 nm.

The material of the second electrode layer 12 is, for example, but not limited to, indium tin oxide, a metal, a metal compound, or a conductive organic material. The metal is, for example, but not limited to, aluminum, gold, silver, calcium, nickel, or chromium. The metal compound is, for example, but not limited to, zinc oxide, molybdenum oxide, or lithium fluoride. The conductive organic material is, for example, but not limited to, polydioxyethylthiophene-polystyrenesulfonic acid [PEDOT: PSS]. The thickness of the second electrode layer 12 ranges from 2 nm to 1000 nm. In the first embodiment, the material of the second electrode layer 12 is indium tin oxide, and the thickness is 200 nm.

The light and gas sensor 13 is located on one surface 111 of the first electrode layer 11. The light and gas sensor 13 is used to interact with the gas to be measured, and includes an organic semiconductor material. The organic semiconductor material is, for example but not limited to, poly (9,9-dioctylfluorene) [poly (9,9-dioctylfluorene), PFO for short], 9,9-dioctylfluorene-benzothiadiazole copolymer [ poly (9,9-dioctylfluorene-co-benzothiadiazole), referred to as F8BT], 9,9-dioctylfluorene-N- (4-butylphenyl) diphenylamine copolymer {poly [9,9-dioctylfluorene-co -N- (4-butylphenyl) diphenylamine], referred to as TFB}, poly (3-hexylthiophene) [poly (3-hexylthiophene), referred to as P3HT], poly {4,8-bis (5- (2-ethyl Hexyl) thiophen-2-yl) benzo [1,2-b; 4,5-b '] dithiophene-2,6-diyl-4- (2-ethylhexyloxycarbonyl) -3- Fluoro-thieno [3,4-b] thiophene-2,6-diyl)} {poly [4,8-bis (5- (2-ethylhexyl) thiophene-2-yl) -benzo [1,2 -b; 4,5-b '] dithiophene-2,6-diyl-4- (2-ethylhexyloxycarbonyl) -3-fluoro-thieno [3,4-b] -thiophene))-2,6-diyl], PBDTTT-EFT}, poly {4,8-bis [(2-ethylhexyl) oxy] benzo [1,2-b; 4,5-b '] dithiophene-2,6-diyl} {3-Fluoro-2-[(2-ethylhexyl) carbonyl] -thieno [3,4-b] thiophene diyl)} {poly [4,8-bis [(2-ethylhexyl) oxy] benzo [1,2-b: 4,5-b '] dithiophene-2,6-diyl] [3-fluoro-2-[(2-ethylhexyl) carbonyl] thie no [3,4-b] -thiophenediyl], referred to as PTB7}, or poly {4,8-bis (5- (2-ethylhexyl) thiophen-2-yl) benzo [1,2-b; 4,5-b '] dithiophene-2,6-diyl-4- (2-ethylhexyl) -thieno [3,4-b] thiophene-2,6-diyl} {poly [ 4,8-bis (5- (2-ethylhexyl) thiophene-2-yl) -benzo [1,2-b; 4,5-b '] dithiophene-2,6-diyl-4- (2-ethylhexanoyl) -thieno [3,4-b] -thiophene) -2,6-diyl], referred to as PBDTTT-CT}, etc. The 9,9-dioctylfluorene-benzothiadiazole copolymer, such as, but not limited to, 9,9-dioctylfluorene-2,1,3-benzothiadiazole copolymer, or 9,9-bis Octylfluorene-1,2,3-benzothiadiazole copolymers and the like. The thickness of the light and gas sensor 13 ranges from 10 nm to 300 nm. In the first embodiment, the thickness of the light and gas sensor 13 is 20 nm.

The light-emitting element 2 is located above the first electrode layer 11 of the gas sensing device 1, and is used to provide the light and gas sensing element after the light and gas sensing element 13 interacts with the gas to be measured. 13 irradiates and passes through the through holes 10 of the first electrode layer 11 to contact the light and the gas sensor 13. The light-emitting element 2 is, for example, a visible light lamp, an ultraviolet light lamp, or an infrared light lamp.

Referring to FIG. 1 and FIG. 3, a second embodiment of a gas sensing device according to the present invention is installed in a glass container 3 as described in the first embodiment, and includes a gas sensing device 1 and a light-emitting element 2.

The gas sensing device 1 includes a first electrode layer 11, a second electrode layer 12 spaced from the first electrode layer 11, a light and gas sensing element 13, and a dielectric layer 14.

The first electrode layer 11 is the same as the first electrode layer 11 of the first embodiment, so it will not be described again. The second electrode layer 12 is spaced from the first electrode layer 11. The second electrode layer 12 is the same as the second electrode layer 12 of the first embodiment, so it will not be described again.

The dielectric layer 14 is located between one surface 111 of the first electrode layer 11 and the second electrode layer 12, and is connected to one surface 111 of the first electrode layer 11 and the second electrode layer 12. The material of the dielectric layer 14 is, for example, but not limited to, poly (vinylphenol) (PVP), polymethylmethacrylate (PMMA), or poly (vinyl alcohol) (PVA) )Wait. The thickness of the dielectric layer 14 ranges from 200 nm to 400 nm. The dielectric layer 14 has a plurality of through-holes 20 communicating with the through-holes 10 of the first electrode layer 11 respectively. The size of the perforations 20 of the dielectric layer 14 ranges from 100 nm to 300 nm.

The light and gas sensing element 13 is disposed opposite to the dielectric layer 14 and is connected to the other surface 111 of the first electrode layer 11 and extends into the through holes 10 and the dielectric of the first electrode layer 11. The through holes 20 of the layer 14 are connected to the second electrode layer 12. The light and gas sensing element 13 is similar to the light and gas sensing element 13 of the first embodiment, so it will not be described again.

The light-emitting element 2 is located above the light and gas sensing element 13 of the gas sensing device 1, and is used to provide a sense of light and gas after the light and gas sensing element 13 interacts with the gas to be measured. Light irradiated by the test piece 13. The light-emitting element 2 is the same as the light-emitting element 2 of the first embodiment, so it will not be described again.

When operating the gas sensing devices of the first and second embodiments, the first electrode layer 11 and the second electrode layer 12 of the gas sensing device 1 are connected to an electrical device (not shown), The electrical equipment includes a voltage supply (not shown) and a current detector (not shown), so as to provide a voltage through the voltage supply and output a current through the current detector. The voltage of the voltage supplier is adjusted according to the light and the gas sensing element 13 selected in the gas sensing device 1. Next, the gas to be measured is introduced into the glass container 3, and the gas to be measured is brought into contact with the light and the gas sensing element 13 of the gas sensing device 1 of the gas sensing device within a sensing period, and here At the same time, the current detector continuously outputs the sensed current value during this sensing period. Then, the gas to be measured is stopped from contacting the light and gas sensing element 13, and the light emitting element 2 is turned on. The light-emitting element 2 emits light irradiated toward the light and gas sensing element 13, and the light is in contact with the light and gas sensing element 13 during a recovery period, and during this recovery period, the current detector It will continuously output the recovery current value.

Referring to Table 1, in the present invention, experimental data of gas sensing devices numbered 1 to 7 is provided. The gas sensing devices of the numbers 1 to 5 are the gas sensing devices of the first embodiment, and the numbers 1 to 5 are different in the material of the sensing member 13 of the gas sensing device 1 and the light emitted by the light emitting member 2. See Table 1. The gas sensing devices of the numbers 6 to 7 are the gas sensing devices of the first embodiment, and are different from the numbers 1 to 5 in that there is no light-emitting member 2 and the air is used for recovery. The test gas is ammonia and its concentration is 300 ppb.

Table 1 Numbering Light and gas sensor 13 Sensing period Illumination 2 During the reply Total time (seconds) 0 second 30 seconds Total time (seconds) 0 second 30 seconds when finished Material Current value (μA) Current value (μA) Light Wavelength (nm) Strength (W / m ² ) Current value (μA) Current value (μA) Current value (μA) 1 PBDTTT-CT 30 0.91 0.78 Ultraviolet light 365 1 32 Current value during the 30th second during induction 2.04 0.93 2 PBDTTT-CT 30 0.91 0.77 Visible light 465 1 41 0.77 0.91 3 PBDTTT-CT 30 0.82 0.69 Infrared light 940 1 250 0.82 0.69 4 P3HT 30 2.40 2.04 Ultraviolet light 365 1 31 2.04 3.35 5 P3HT 30 2.31 1.94 Visible light 465 1 32 1.94 2.44 6 PBDTTT-CT 30 0.76 0.63 no - - 265 0.76 0.63 7 P3HT 30 1.90 1.43 no - - 305 1.90 1.90

In order to explain why the gas sensing device of the present invention can quickly increase the current value generated after sensing and return to the current value before sensing, one of the main contributions is from being able to write a light signal into the current signal. The present invention provides a The test example of the gas sensing device can be used to obtain the desorption amount of the gas to be measured during the recovery period. The gas sensing device of this test example is installed in a transparent glass container 3 filled with nitrogen or air, and includes a gas sensing device 1 and a light-emitting element 2. The glass container 3 is as described above. Referring to FIG. 4, the gas sensing device 1 includes a first electrode layer 11, a second electrode layer 12 spaced from the first electrode layer 11, and a second electrode layer located on the first electrode layer 11 and opposite to the second electrode. The light and gas sensing element 13 of the layer 12 and a light and gas sensing element 13 located between the first electrode layer 11 and the second electrode layer 12 and opposite to the light and gas sensing element 13 and connected to the first electrode layer 11 and the first The piezoelectric layer 15 of the two electrode layers 12.

The first electrode layer 11 has two opposite surfaces 111. The material of the first electrode layer 11 is gold. The material of the second electrode layer 12 is gold. The light and gas sensor 13 and the piezoelectric layer 15 are respectively located on the surfaces 111 of the first electrode layer 11, and the piezoelectric layer 15 is located between the first electrode layer 11 and the second electrode layer 12. The material of the light and gas sensor 13 is the same as that of the light and gas sensor 13 of the first embodiment. The material of the piezoelectric layer 15 is quartz. The light-emitting element 2 is the same as the light-emitting element 2 of the first embodiment. The first electrode layer 11, the second electrode layer 12 and the piezoelectric layer 15 of the gas sensing device 1 are wafers in a crystal oscillator measurement system using a model QCM922A of Seiko EG & G, Japan.

When operating the gas sensing device of the test example, the first electrode layer 11 and the second electrode layer 12 of the gas sensing device 1 are connected to an electrical device (not shown), and the electrical device includes a frequency Counter (not shown). The gas to be measured is introduced into the glass container 3, and the gas to be measured is brought into contact with the light and gas sensing element 13 of the gas sensing device 1 of the gas sensing device within a sensing period, and at the same time, The frequency counter continuously outputs a sensed frequency value during this sensing period. Then, the gas to be measured is stopped from contacting the light and gas sensing element 13, and the light emitting element 2 is turned on. The light-emitting element 2 emits light irradiated toward the light and the gas sensing element 13, and the light is in contact with the light and the gas sensing element 13 during a recovery period, and during this recovery period, the frequency counter The response frequency value is continuously output. The sensing frequency value and the recovery frequency value are brought into a sauerbrey equation, and the adsorption amount and desorption amount of the gas to be measured are converted.

Refer to FIG. 5, which is a data chart obtained by using a gas sensing device of No. 2 under illuminated and unlit conditions, with a peak bottom as a boundary line, and the current change rate during the sensing period before the peak bottom. After the peak bottom is the current change rate during the recovery period, where the upper line is performed under the condition with light, and the lower line is performed under the condition without light. The current change rate is [(AB) / A ] × 100%, A represents the current value when the light and gas sensing element 13 does not interact with the gas to be measured, and B represents the current value during the sensing period or the current value during the recovery period. Refer to FIG. 6, which is a data chart obtained by using a gas sensing device of a test example under illuminated and unlit light, with a peak bottom as a boundary line, and before the peak bottom, a frequency difference value during the sensing period. After the bottom of the peak is the frequency difference during the recovery period, where the upper line is performed with light, and the lower line is performed without light. The frequency difference is (CD), and C indicates the light. And the frequency value when the gas sensing element 13 is not interacting with the gas to be measured, and D represents the frequency value during the sensing period or the frequency value during the recovery period. It can be seen from the upper line in FIG. 6 that at the 30th second of the recovery period, the frequency value generated after the sensing rises but does not return to the frequency value before the sensing, indicating that the gas to be measured is at the 30th second of the recovery period. It is not completely desorbed from the light and gas sensor 13, but it can be seen from the upper line of FIG. 5 that at the 30th second of the recovery period, the current value generated after sensing has picked up and has returned to the value before the sensing. It can be known from this that during the recovery process, the contribution of the current value generated after sensing is not only the desorption of the gas to be measured by light, but also the light and the gas sensing element 13 can absorb light. The optical signal can be written into the current signal, so that the current value generated after sensing can be quickly recovered and returned to the current value before sensing.

In summary, through the combination of the light-emitting element 2 and the light and gas sensing element 13, the light-emitting element 2 is turned on after sensing. During the recovery process, since the light and gas sensing element 13 can absorb light The light signal can be written into the current signal, and at the same time, the light can also promote the desorption of the gas to be measured, so that the current value generated after the sensing can be quickly recovered and restored to the current value before the sensing, thereby improving the recovery efficiency. For the next sensing. Therefore, the gas sensing device of the present invention has a short current recovery time, so it can indeed achieve the purpose of the present invention.

However, the above are only examples of the present invention. When the scope of implementation of the present invention cannot be limited by this, any simple equivalent changes and modifications made according to the scope of the patent application and the contents of the patent specification of the present invention are still Within the scope of the invention patent.

1‧‧‧Gas sensing device

11‧‧‧first electrode layer

111‧‧‧ surface

10‧‧‧ through hole

12‧‧‧Second electrode layer

13‧‧‧Light and gas sensor

14‧‧‧ Dielectric layer

15‧‧‧piezoelectric layer

20‧‧‧ perforation

2‧‧‧lighting parts

3‧‧‧ glass container

31‧‧‧air inlet

32‧‧‧air outlet

Other features and effects of the present invention will be clearly presented in the embodiment with reference to the drawings, in which: FIG. 1 is a schematic diagram of a first embodiment of a gas sensing device of the present invention; FIG. 2 is a schematic view of the embodiment A schematic diagram of a gas sensing device; FIG. 3 is a schematic diagram of a gas sensing device of a second embodiment of a gas sensing device of the present invention; FIG. 4 is a schematic diagram of a gas sensing device of a test example; FIG. 5 is a data diagram illustrating the current recovery of an embodiment of the gas sensing device of the present invention with and without light; and FIG. 6 is a data diagram illustrating a test example of a gas sensing device. Current recovery with and without light.

Claims (5)

A gas sensing device includes: a gas sensing device including a light and gas sensing element for interacting with a gas to be measured and including an organic semiconductor material; a first electrode layer connected to the light and gas sensing A light source and a second electrode layer spaced apart from the first electrode layer and connected to the light and gas sensing element; and a light emitting element spaced from the sensing device and positioned between the light and gas sensing element and the The gas to be measured is used to provide light that is irradiated toward the light and the gas sensing element and can be absorbed by the light and the gas sensing element. The gas sensing device according to claim 1, wherein the light-emitting element is an ultraviolet light lamp or a visible light lamp. The gas sensing device according to claim 1, wherein the light and gas sensing element is located between the first electrode layer and the second electrode layer, and the first electrode layer has light passing through the light emitting element to communicate with At least one through hole contacted by the light and gas sensing element. The gas sensing device according to claim 1, wherein the first electrode layer has at least one through hole; the gas sensing device further comprises a layer located between the first electrode layer and the second electrode layer and connected to the first electrode layer An electrode layer and a dielectric layer of the second electrode layer, the dielectric layer having at least one perforation communicating with the at least one through hole; the light and gas sensing element and the dielectric layer are respectively located on the first electrode layer Two oppositely disposed surfaces, and the light and gas sensing element is connected to the surface of the first electrode layer and extends into the at least one through hole of the first electrode layer and the at least one perforation of the dielectric layer to connect The second electrode layer. The gas sensing device according to claim 1, wherein the organic semiconductor material is selected from the group consisting of poly (9,9-dioctylfluorene), 9,9-dioctylfluorene-benzothiadiazole copolymer, 9,9-dioctylfluorene-N- (4-butylphenyl) diphenylamine copolymer, poly (3-hexanethiothiophene), poly {4,8-bis (5- (2-ethylhexyl) ) Thiophen-2-yl) benzo [1,2-b; 4,5-b '] dithiophene-2,6-diyl-4- (2-ethylhexyloxycarbonyl) -3-fluoro -Thieno [3,4-b] thiophen-2,6-diyl)}, poly {4,8-bis [(2-ethylhexyl) oxy] benzo [1,2-b; 4, 5-b '] dithiophene-2,6-diyl} {3-fluoroyl-2-[(2-ethylhexyl) carbonyl] -thieno [3,4-b] thiophenediyl)}, or , Poly {4,8-bis (5- (2-ethylhexyl) thiophen-2-yl) benzo [1,2-b; 4,5-b '] dithiophene-2,6-diyl- 4- (2-ethylhexyl) -thieno [3,4-b] thiophene-2,6-diyl}.