RO135493A2

RO135493A2 - Ternary sensitive layer for resistive humidity sensor

Info

Publication number: RO135493A2
Application number: RO202000481A
Authority: RO
Inventors: Bogdan Cătălin Serban; Octavian Buiu; Cornel Cobianu; Viorel Marian Avramescu; Niculae Dumbravescu
Original assignee: Institutul Naţional De Cercetare-Dezvoltare Pentru Microtehnologie-Imt Bucureşti
Priority date: 2020-07-31
Filing date: 2020-07-31
Publication date: 2022-01-28

Abstract

The invention relates to a resistive sensor for measuring relative humidity in various fields of domestic and industrial activities, such as the textile and paper industry, the medical field, the pharmaceutical industry, the food industry, agriculture, the electronics industry and the like. According to the invention, the sensor consists of a dielectric substrate which may be made of Si/SiO2, glass or polyimide with a thickness of between 50 μm and 5 mm, over which electrodes which may have a linear or interdigitated configuration are deposited, by direct printing, cathode sputtering or by evaporation, where the electrodes may be made of the same material of Al, Cr, Cu or Au or of different materials, and finally, a sensitive layer consisting of a thin film of ternary nanocomposite such as oxidized carbon nanohorns/SnO2/polyvinylpyrrolidone or oxidized carbon materials such as nano onion/SnO2/polyvinylpyrrolidone is deposited over the electrode substrate, the oxidized carbon nanohorns and onion-type oxidized carbon materials being in a percentage of 50% by mass, and the SnO2 and polyvinylpyrrolidone in equimass ratios, the deposition of the sensitive layer being made from ethyl alcohol solution, by drop casting.

Description

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DescriereDescription

Umiditatea este unul dintre parametrii fizici monitorizați cel mai frecvent și are o mare importanță în multiple domenii de activitate casnică și industrială, precum industria textilă și a hârtiei, domeniul medical (centre de transfuzie, incinte de sterilizare), controlul calității aerului în spații închise, meteorologie (radiosonde, baloane meteorologice), industria farmaceutică (sinteza și controlul calității medicamentelor, monitorizarea spațiilor de depozitare a medicamentelor), agricultură (controlul umidității solului, silozuri), industria alimentară (spații de producție și stocare a alimentelor), industria electronică, industria auto, etc. [1 - 3]. Astfel, fabricarea unor senzori performanți de umiditate a devenit o direcție prioritară în ultimele decade.Humidity is one of the most frequently monitored physical parameters and is of great importance in many areas of domestic and industrial activity, such as the textile and paper industry, the medical field (transfusion centers, sterilization premises), indoor air quality control, meteorology (radiosondes, balloons), pharmaceutical industry (synthesis and quality control of medicines, monitoring of drug storage facilities), agriculture (soil moisture control, silos), food industry (food production and storage facilities), electronics industry, industry car, etc. [1 - 3]. Thus, the manufacture of high-performance humidity sensors has become a priority in recent decades.

Polielectroliții [4-6], sărurile anorganice[7,8], polimerii[ 9-12] sunt materiale utilizate pe scară largă în monitorizarea umidității relative. Oxizii metalici semiconductori pot fi, de asemenea, folosiți ca straturi senzitive în manufacturarea senzorilor de umiditate, oxidul de staniu fiind unul dintre cei mai utilizați[l3-27],Polyelectrolytes [4-6], inorganic salts [7,8], polymers [9-12] are materials widely used in monitoring relative humidity. Semiconductor metal oxides can also be used as sensitive layers in the manufacture of humidity sensors, with tin oxide being one of the most widely used [l3-27],

Cererea de brevet de invenție KR20020029030A cu titlul Humidity sensor using nanostructured SnChiTiCh multilayer thin fllms ( EH§is) se referă la un senzor rezistiv de umiditate utilizând ca straturi senzitive matrice nanocompozită de tipul SnO2-TiO2 monostrat și multistrat. Substratul este constituit din alumină, iar electrozii sunt realizați din argint. Monostratul are o grosime ce variază între 480 și 500 nm (cu o dimensiune a particulelor de 7,9 - 10,8 nm), multistratul având o grosime ce variază între 620 to 670nm (cu o dimensiune a particulelor de 7,6- 11,5 nm).Patent application KR20020029030A entitled Humidity sensor using nanostructured SnChiTiCh multilayer thin fllms (EH§is) relates to a moisture resistive sensor using as monolayer and multilayer SnO2-TiO2 nanocomposite matrix as sensitive layers. The substrate is made of alumina and the electrodes are made of silver. The monolayer has a thickness ranging from 480 to 500 nm (with a particle size of 7.9 - 10.8 nm), the multilayer having a thickness ranging from 620 to 670nm (with a particle size of 7.6 - 11 , 5 nm).

Cererea de brevet de invenție KR20020023937A cu titlul Humidity sensor using nanosized andporous TiOj-SnCh thin films (EH ξ) se referă la un senzor rezistiv de umiditate utilizând ca straturi senzitive matrice nanocompozită de tipul TiO2-SnO2 ( procentul masic de SnO2 variind între 0 -40%).Substratul este constituit din alumină, iar electrozii sunt realizați din argint. După depunerea soluției prin metoda “spin coating”, stratul senzitiv ( cu o grosime cuprinsă între 480 și 580 nm) este înc ă Izit la 500°C timp de 30 de minute. Dimensiunea particulelor variază între 10.8-13.1nm. Rezistența stratului senzitiv variază cu schimbarea nivelului umidității relative.Patent application KR20020023937A entitled Humidity sensor using nanosized and porous TiOj-SnCh thin films (EH ξ) relates to a resistive humidity sensor using as sensitive layers a nanocomposite matrix type TiO2-SnO2 (mass percentage of SnO2 ranging from 0 - The substrate is made of alumina and the electrodes are made of silver. After depositing the solution by the spin coating method, the sensitive layer (with a thickness between 480 and 580 nm) is still heated at 500 ° C for 30 minutes. The particle size varies between 10.8-13.1nm. The resistance of the sensitive layer varies with the change of the relative humidity level.

Cererea de brevet de invenție CN85107480A cu titlul Ceramic moisture sensor $^) se referă la un senzor rezistiv de umiditate utilizând ca straturi senzitive matrice nanocompozită de tipul ZnCr2O4-LiZnVO4, dopată cu Y2O3 și SnO2. Timpul de răspuns al senzorului (în intervalul 50-90% RH) este de 20 secunde, acuratețea măsurătorii fiind < 4% RH. Coeficientul de temperatură al senzorului revendicat este 0.3% RH/C°.Patent application CN85107480A entitled Ceramic moisture sensor $ ^) relates to a moisture resistive sensor using as sensitive layers a ZnCr2O4-LiZnVO4 nanocomposite matrix, doped with Y2O3 and SnO2. The response time of the sensor (in the range of 50-90% RH) is 20 seconds, the accuracy of the measurement being <4% RH. The temperature coefficient of the claimed sensor is 0.3% RH / C °.

Nanohornurile carbonice sunt materiale cu o structură tubulară, înrudite cu nanotuburile de carbon [28, 29], Ele se pot sintetiza prin ablația laser a grafitului. Nanohornurile carbonice oxidate (Fig. 1) au un caracter hidrofil, sunt ușor dispersabile în apă și solvenți organici (etanol, alcool izopropilic) și prezintă o suprafață specifică mare (1300-1400 m²/g) [30, 31], în pofida paletei largi de aplicații, există un număr relativ mic de studii privind utilizările nanohomurilor carbonice (simple și oxidate) ca straturi senzitive pentru diverse tipuri de gaze [32, 33],Carbon nanohorns are materials with a tubular structure, related to carbon nanotubes [28, 29]. They can be synthesized by laser ablation of graphite. Oxidized carbon nanohorns (Fig. 1) have a hydrophilic character, are easily dispersible in water and organic solvents (ethanol, isopropyl alcohol) and have a large specific surface area (1300-1400 m ² / g) [30, 31], despite a wide range of applications, there are a relatively small number of studies on the use of carbon nanoparticles (simple and oxidized) as sensitive layers for various types of gases [32, 33],

Cererea de brevet de invenție RO133636A2 cu titlul Senzor chemirezistiv de etanol, (Bogdan Cătălin Serban, Octavian Buiu, Cornel Cobianu Octavian Narcis lonescu, Maria Roxana Marinescu Niculae Dumbravescu) se referă la un senzor rezistiv de etanol utilizând ca straturi senzitive matrice nanocompozite de tip T1O2/ La2O3/nanohomuri carbonice oxidate. Sinteza nanohomurilor oxidate se realizează prin două metode diferite, utilizând tratamentul în plasma de oxigen și respectiv oxidarea cu apă oxigenată la 100°C.The patent application RO133636A2 with the title Ethanol chemoresistive sensor, (Bogdan Cătălin Serban, Octavian Buiu, Cornel Cobianu Octavian Narcis lonescu, Maria Roxana Marinescu Niculae Dumbravescu) refers to an ethanol resistive sensor using nanocomposite T / La2O3 / oxidized carbon nanowires. The synthesis of oxidized nanowires is performed by two different methods, using plasma oxygen treatment and oxidation with hydrogen peroxide at 100 ° C, respectively.

Materialele nanocarbonice de tip ceapă (“carbon nano-onions”- CNOs) au fost sintetizate în premieră de către Ugarte în 1992 prin iradierea cu electroni a funinginei [34], Din punct de vedere structural, CNOs fac parte din familia fulerenelor și sunt constituite din straturi grafitice cvasi-sferice sau de formă poliedrică [35].Onion-type carbon nano-onions (CNOs) were first synthesized by Ugarte in 1992 by electron irradiation of soot [34]. Structurally, CNOs are part of the fullerene family and are from quasi-spherical or polyhedral graphitic layers [35].

Oxidările cu ozon sau acid azotic conduc la formarea unor structuri nanocarbonice de tip ceapă, funcționalizate cu grupări polare de tip carboxil, hidroxil, carbonil (Ox- CNOs) care măresc substanțial solubilitatea CNOs (Fig. 2) în solvenți polari precum metanol, apă, tetrahidrofuran, etc.Oxidations with ozone or nitric acid lead to the formation of onion-type nanocarbon structures, functionalized with polar groups such as carboxyl, hydroxyl, carbonyl (Ox-CNOs) which substantially increase the solubility of CNOs (Fig. 2) in polar solvents such as methanol, water, tetrahydrofuran, etc.

Datorită excelentelor proprietăți fizico-chimice (suprafață specifică ridicată, remarcabilă conductivitate electrică, mezoporozitate mare), CNOs se utilizează în designul senzorilor chimici [36-38].Due to the excellent physico-chemical properties (high specific surface area, remarkable electrical conductivity, high mesoporosity), CNOs are used in the design of chemical sensors [36-38].

Problema tehnică pe care o rezolvă invenția prezentă constă în obținerea de noi straturi senzitive la variația valorii umidității relative, utilizate în designul unor senzori de tip rezistiv. Straturile senzitive descrise în această invenție, care pot fi utilizate pentru obținerea unor senzori rezistivi de umiditate relativă, sunt matrice nanocompozite de tipul nanohornuri carbonice oxidate/SnO2/ polivinilpirolidonă și, respectiv, nanocarbonice oxidate de tip ceapă /SnO2/ polivinilpirolidonă. Din punct de vedere al principiului de detecție, rezistența stratului conductiv variază cu nivelul umidității relative.The technical problem solved by the present invention consists in obtaining new sensitive layers to the variation of the relative humidity value, used in the design of resistive type sensors. The sensitive layers described in this invention, which can be used to obtain resistive sensors of relative humidity, are nanocomposite matrices of the type oxidized carbon nanohorns / SnO2 / polyvinylpyrrolidone and, respectively, oxidized nanocarbons of the onion / SnO2 / polyvinylpyrrolidone type. From the point of view of the detection principle, the resistance of the conductive layer varies with the level of relative humidity.

Utilizarea nanocompozitelor ternare ca strat senzitiv în monitorizarea umidității relative prezintă câteva avantaje semnificative:The use of ternary nanocomposites as a sensitive layer in monitoring relative humidity has several significant advantages:

• nanohornurile carbonice oxidate, precum și materialele nanocarbonice oxidate de tip ceapă conferă un raport mare suprafață specifică / volum, afinitate pentru moleculele de apă, precum și o variație a rezistenței stratului senzitiv la contactul cu acestea pe tot domeniul de RH;• oxidized carbon nanocorns, as well as onion-type oxidized nanocarbon materials provide a high specific area / volume ratio, affinity for water molecules, as well as a variation of the resistance of the sensitive layer to contact with them throughout the RH domain;

• detecție la temperatura camerei;• room temperature detection;

Polivinilpirolidonă este un polimer hidrofil, cu excelente proprietăți de binder;Polyvinylpyrrolidone is a hydrophilic polymer with excellent binder properties;

• SnO2 este un oxid semiconductor foarte sensibil la schimbarea nivelului umidității relative.• SnO2 is a semiconductor oxide that is very sensitive to changes in relative humidity.

Substratul senzorului este realizat din siliciu (470 microni) acoperit cu SiO? (1 micron). Electrozii au fost conectați prin depunerea succesivă de Cr (10 nm) și Au (100 nm). Lățimea electrozilor este de aproximativ 200 microni, cu o separare de 6 mm între ele. Ei pot fi liniariIs the sensor substrate made of silicon (470 microns) coated with SiO? (1 micron). The electrodes were connected by successive deposition of Cr (10 nm) and Au (100 nm). The width of the electrodes is about 200 microns, with a separation of 6 mm between them. They can be linear

(Fig. 3) sau pot avea o configurație interdigitată (Fig. 4). Capacitatea de monitorizare a umidității relative a fost investigată prin aplicarea unui curent constant între cei doi electrozi și măsurarea tensiunii la diferite valori ale nivelului de umiditate relativă la care a fost expus stratul senzitiv de tipul nanohomuri carbonice oxidate/SnCh/ polivinilpirolidonă și materiale nanocarbonice oxidate de tip ceapă /SnO2/ polivinilpirolidonă.(Fig. 3) or may have an interdigitated configuration (Fig. 4). The ability to monitor relative humidity was investigated by applying a constant current between the two electrodes and measuring the voltage at different values of the relative humidity level to which the sensitive layer such as oxidized carbon nanowires / SnCh / polyvinylpyrrolidone and oxidized nanocarbon materials were exposed. onion type / SnO2 / polyvinylpyrrolidone.

în cele ce urmează se prezintă etapele necesare pentru obținerea straturilor senzitive la umiditate relativă,precum și pentru obținerea senzorilor rezistivi de umiditate relativă.The following are the steps required to obtain the relative humidity sensitive layers as well as to obtain the relative humidity resistive sensors.

Exemplul 1Example 1

Materiile prime necesare sintezei stratului senzitiv sunt, în primul caz, polivinilpirolidonă (M= 1.300.000 Da), nanohornurile carbonice oxidate și SnO2 (nanopudră, dimensiunea particulelor < de 100 nanometri), alcoolul etilic. Toate materialele sunt achiziționate de la Sigma Aldrich.The raw materials necessary for the synthesis of the sensitive layer are, in the first case, polyvinylpyrrolidone (M = 1,300,000 Da), oxidized carbon nanohorns and SnO2 (nanopowder, particle size <100 nanometers), ethyl alcohol. All materials are purchased from Sigma Aldrich.

1) Soluția de polivinilpirolidonă se prepară prin dizolvarea a 1 mg polimer în 10 mL alcool etilic, sub agitare magnetică timp de trei ore, la temperatura camerei.1) The solution of polyvinylpyrrolidone is prepared by dissolving 1 mg of polymer in 10 mL of ethyl alcohol, under magnetic stirring for three hours, at room temperature.

2) Se adaugă soluției preparate anterior 2 mg nanohomuri carbonice oxidate și se continuă agitarea magnetică timp de trei ore, la temperatura camerei.2) Add to the previously prepared solution 2 mg of oxidized carbon nanowires and continue stirring magnetically for three hours at room temperature.

3) Soluției preparate anterior i se adaugă 1 mg SnO2 și se continuă agitarea magnetică timp de 12 ore, la temperatura camerei.3) Add 1 mg SnO2 to the previously prepared solution and continue stirring magnetically for 12 hours at room temperature.

4) Dispersia obținută se depune prin metodadrop casting utilizând un substrat de Si/SiO₂ cu electrozi liniari sau cu electrozi interdigitați (după ce în prealabil s-a realizat mascarea zonei de contacte).4) The dispersion obtained is deposited by metadrop casting using a Si / SiO ₂ substrate with linear electrodes or interdigitated electrodes (after previously masking the contact area).

5) Stratul senzitiv obținut se supune unui tratament termic la 80°C, două ore,în vid. Capacitatea de monitorizare a umidității relative a fost investigată prin aplicarea unui curent între cei doi electrozi și măsurarea tensiunii la diferite valori ale nivelului de umiditate relativă la care a fost expus stratul senzitiv nanohomuri carbonice oxidate/SnO2/ polivinilpirolidonă ( PVP). Măsurătorile au fost efectuate în azot, la temperatura camerei, la diferite valori ale umidității relative. în Fig. 5 se prezintă o comparație între performanța senzorului de umiditate care utilizează stratul senzitiv obținut în exemplul 1( curba R) și a senzorului de umiditate de tip capacitiv, comercializat de firma Honeywell( curba RH).5) The sensitive layer obtained is subjected to a heat treatment at 80 ° C, two hours, in a vacuum. The ability to monitor relative humidity was investigated by applying a current between the two electrodes and measuring the voltage at different values of the relative humidity level to which the sensitive layer of oxidized carbon nanowires / SnO2 / polyvinylpyrrolidone (PVP) was exposed. Measurements were made in nitrogen at room temperature at different relative humidity values. in FIG. 5 shows a comparison between the performance of the humidity sensor using the sensitive layer obtained in Example 1 (R curve) and the capacitive type humidity sensor, marketed by Honeywell (RH curve).

Exemplul 2Example 2

Materiile prime necesare sintezei stratului senzitiv sunt, în primul caz, polivinilpirolidonă (M= 1.300.000 Da) nanodiamantul și SnO2 (nanopudră, dimensiunea particulelor < de 100 nanometri), alcoolul izopropilic. Toate materialele sunt achiziționate de la Sigma Aldrich.The raw materials necessary for the synthesis of the sensitive layer are, in the first case, polyvinylpyrrolidone (M = 1,300,000 Da) nanodiamond and SnO2 (nanopowder, particle size <100 nanometers), isopropyl alcohol. All materials are purchased from Sigma Aldrich.

1) Materialele nanocarbonice de tip ceapă (CNOs) se sintetizează din nanodiamant, prin tratament termic la 1650°C, în atmosferă de heliu.1) Onion-type nanocarbon materials (CNOs) are synthesized from nanodiamond, by heat treatment at 1650 ° C, in a helium atmosphere.

2) Sinteza materialelor nanocarbonice oxidate (hidrofile) de tip ceapă se realizează prin reacția cu acid azotic 3M, la reflux, timp de 48 h. Produsul obținut se spală cu apă deionizată, acetonă, si final, cu apă deionizată.2) The synthesis of oxidized nanocarbon materials (hydrophilic) of onion type is performed by reaction with 3M nitric acid, at reflux, for 48 hours. The product obtained is washed with deionized water, acetone, and finally with deionized water.

3) Soluția de polivinilpirolidonă se prepară prin dizolvarea a 1 mg polimer în 10 mL alcool etilic, sub agitare magnetică (timp de două ore, la temperatura camerei).3) The polyvinylpyrrolidone solution is prepared by dissolving 1 mg of polymer in 10 mL of ethyl alcohol under magnetic stirring (for two hours at room temperature).

4) Se adaugă soluției preparate anterior 2 mg materiale nanocarbonice oxidate de tip ceapă și se continuă agitarea magnetică timp de trei ore, la temperatura camerei.4) Add to the previously prepared solution 2 mg of onion-type oxidized nanocarbon materials and continue stirring magnetically for three hours at room temperature.

5) Soluției preparate anterior i se adaugă 1 mg SnO2 și se continuă agitarea magnetică timp de 12 ore, la temperatura camerei.5) Add 1 mg SnO2 to the previously prepared solution and continue stirring magnetically for 12 hours at room temperature.

6) Dispersia obținută se depune prin metodadrop casting utilizând un substrat de Si/SiO₂ cu electrozi liniari sau cu electrozi interdigitați (după ce în prealabil s-a realizat mascarea zonei de contacte).6) The dispersion obtained is deposited by metadrop casting using a Si / SiO ₂ substrate with linear electrodes or interdigitated electrodes (after previously masking the contact area).

7) Stratul senzitiv obținut se supune unui tratament termic la 80°C, doua ore,în vid.7) The sensitive layer obtained is subjected to a heat treatment at 80 ° C, two hours, in a vacuum.

Capacitatea de monitorizare a umidității relative a fost investigată prin aplicarea unui curent între cei doi electrozi și măsurarea tensiunii la diferite valori ale nivelului de umiditate relativă la care a fost expus stratul sensibil. Măsurătorile au fost efectuate în azot, la temperatura camerei, la diferite valori ale umidității relative.The relative humidity monitoring capability was investigated by applying a current between the two electrodes and measuring the voltage at different values of the relative humidity level to which the sensitive layer was exposed. Measurements were made in nitrogen at room temperature at different relative humidity values.

1. Rittersma, Z. M. (2002), Recent achievements in miniaturized humidity sensors—a review of transduction techniques. Sensors and Actuators A: Physical, 96(2-3), 196 - 210.1. Rittersma, Z. M. (2002), Recent achievements in miniaturized humidity sensors — a review of transduction techniques. Sensors and Actuators A: Physical, 96 (2-3), 196 - 210.

2. Chen, Z., Lu, C. (2005), Humidity sensors: a review of materials and mechanisms. Sensor Letters, 3(4), 274 - 295.2. Chen, Z., Lu, C. (2005), Humidity sensors: a review of materials and mechanisms. Sensor Letters, 3 (4), 274 - 295.

3. Lee, C. Y., Lee, G. B. (2005) Humidity sensors: a review. Sensor Letters, 3(1-1), 1-153. Lee, C. Y., Lee, G. B. (2005) Humidity sensors: a review. Sensor Letters, 3 (1-1), 1-15

4. Su, P. G., & Cheng, K. H. (2009). Self-assembly of polyelectrolytic multilayerthin films of polyelectrolytes on quartz crystal microbalance for detecting low humidity. Sensors and Actuators B: Chemical, 142()), 123-129.4. Su, P. G., & Cheng, K. H. (2009). Self-assembly of polyelectrolytic multilayerthin films of polyelectrolytes on quartz crystal microbalance for detecting low humidity. Sensors and Actuators B: Chemical, 142 ()), 123-129.

5. Guenther, M., Gerlach, G., & Wallmersperger, T. (2007, April). Modeling of the nonlinear effects in pH sensors based on polyelectrolytic hydrogels. In Electroactive Polymer Actuators and Devices (EAPAD) 2007 (Voi. 6524, p. 652417). International Society for Optics and Photonics.5. Guenther, M., Gerlach, G., & Wallmersperger, T. (2007, April). Modeling of the nonlinear effects in pH sensors based on polyelectrolytic hydrogels. In Electroactive Polymer Actuators and Devices (EAPAD) 2007 (Vol. 6524, p. 652417). International Society for Optics and Photonics.

6. Lv, X., Li, Y., Li, P., & Yang, M. (2009). A resistive-type humidity sensor based on crosslinked polyelectrolyte prepared by UV irradiation. Sensors and Actuators B: Chemical, /35(2), 581-586.6. Lv, X., Li, Y., Li, P., & Yang, M. (2009). A resistive-type humidity sensor based on crosslinked polyelectrolyte prepared by UV irradiation. Sensors and Actuators B: Chemical, / 35 (2), 581-586.

7. Jiang, K., Zhao, H., Dai, J., Kuang, D., Fei, T., & Zhang, T. (2016). Excellent humidity sensor based on LiCl loaded hierarchically porous polymeric microspheres. ACS applied materials & interfaces, A(38), 25529-25534.7. Jiang, K., Zhao, H., Dai, J., Kuang, D., Fei, T., & Zhang, T. (2016). Excellent humidity sensor based on LiCl loaded hierarchically porous polymeric microspheres. ACS applied materials & interfaces, A (38), 25529-25534.

8. Liang, S., He, X., Wang, F., Geng, W., Fu, X., Ren, J., & Jiang, X. (2015). Highly sensitive humidity sensors based on LiCI-Pebax 2533 composite nanofibers via electrospinning. Sensors and Actuators B: Chemical, 208, 363-368.8. Liang, S., He, X., Wang, F., Geng, W., Fu, X., Ren, J., & Jiang, X. (2015). Highly sensitive humidity sensors based on LiCI-Pebax 2533 composite nanofibers via electrospinning. Sensors and Actuators B: Chemical, 208, 363-368.

9. Liu, Y., Huang, H., Wang, L., Cai, D., Liu, B., Wang, D.,... & Wang, T. (2016). Electrospun CeO? nanoparticles/PVP nanofibers based high-frequency surface acoustic wave humidity sensor. SensorsandActuators B: Chemical, 223, 730-737.9. Liu, Y., Huang, H., Wang, L., Cai, D., Liu, B., Wang, D., ... & Wang, T. (2016). Electrospun CeO? nanoparticles / PVP nanofibers based high-frequency surface acoustic wave humidity sensor. SensorsandActuators B: Chemical, 223, 730-737.

10. De Queiroz, A. A., Soares, D. A., Trzesniak, P., & Abraham, G. A. (2001). Resistive-type humidity sensors based on PVP-Co and PVP-I2 complexes. Journal of Polymer Science Part B: Polymer Physics, 39(4), 459-469.10. De Queiroz, A. A., Soares, D. A., Trzesniak, P., & Abraham, G. A. (2001). Resistive-type humidity sensors based on PVP-Co and PVP-I2 complexes. Journal of Polymer Science Part B: Polymer Physics, 39 (4), 459-469.

ll.Azmer, M. L, Zafar, Q., Ahmad, Z., &Sulaiman, K. (2016). Humidity sensor based on electrospun MEH-PPV: PVP microstructured composite. RSC advances, 6(42), 35387-35393.ll.Azmer, M. L, Zafar, Q., Ahmad, Z., & Sulaiman, K. (2016). Humidity sensor based on electrospun MEH-PPV: PVP microstructured composite. RSC advances, 6 (42), 35387-35393.

ll.Sakai, Y., Sadaoka, Y., Matsuguchi, M., & Rao, V. L. (1989). Humidity sensor using microporous film of polyethylene-graft-poly-(2-hydroxy-3-methacryloxypropyl trimethylammonium chloride). Journal of materials Science, 24(\), 101-104ll.Sakai, Y., Sadaoka, Y., Matsuguchi, M., & Rao, V. L. (1989). Humidity sensor using microporous film of polyethylene-graft-poly- (2-hydroxy-3-methacryloxypropyl trimethylammonium chloride). Journal of Materials Science, 24 (\), 101-104

13. Kuang, Q., Lao, C., Wang, Z. L., Xie, Z., & Zheng, L. (2007). High-sensitivity humidity sensor based on a single SnO2 nanowire. Journal of the American Chemical Society, 129()9), 6070-6071.13. Kuang, Q., Lao, C., Wang, Z. L., Xie, Z., & Zheng, L. (2007). High-sensitivity humidity sensor based on a single SnO2 nanowire. Journal of the American Chemical Society, 129 () 9), 6070-6071.

14. Tai, W. P., & Oh, J. H. (2002). Fabrication and humidity sensing properties of nanostructured TiO2-SnO2 thin films. Sensors andActuators B: Chemical, 85()-2), 154-157.14. Tai, W. P., & Oh, J. H. (2002). Fabrication and humidity sensing properties of nanostructured TiO2-SnO2 thin films. Sensors and Actuators B: Chemical, 85 () - 2), 154-157.

2/2/

15. Song, X., Qi, Q., Zhang, T., & Wang, C. (2009). A humidity sensor based on KCl-doped SnO₂ nanofibers. Sensors andActuators B: Chemical, 138(1), 368-373.15. Song, X., Qi, Q., Zhang, T., & Wang, C. (2009). A humidity sensor based on KCl-doped SnO ₂ nanofibers. Sensors and Actuators B: Chemical, 138 (1), 368-373.

16. Parthibavarman, M., Hariharan, V., & Sekar, C. J. M. S. (2011). High-sensitivity humidity sensor based on SnO₂ nanoparticles synthesized by microwave irradiation method. Materials Science and Engineering: C, 31(5), 840-844.16. Parthibavarman, M., Hariharan, V., & Sekar, CJMS (2011). High-sensitivity humidity sensor based on SnO ₂ nanoparticles synthesized by microwave irradiation method. Materials Science and Engineering: C, 31 (5), 840-844.

17. Pascariu, P., Airinei, A., Olaru, N., Petrila, I., Nica, V., Sacarescu, L., & Tudorache, F. (2016). Microstructure, electrica! and humidity sensor properties of electrospun NiO-SnO₂nanofibers. Sensors and Actuators B: Chemical, 222, 1024-1031.17. Pascariu, P., Airinei, A., Olaru, N., Petrila, I., Nica, V., Sacarescu, L., & Tudorache, F. (2016). Microstructure, electrical! and humidity sensor properties of electrospun NiO-SnO ₂ nanofibers. Sensors and Actuators B: Chemical, 222, 1024-1031.

18. Tai, W. P., & Oh, J. H. (2002). Preparation and humidity sensing behaviors of nanocrystalline SnO₂/TiO₂ bilayered films. Thin solidfilms, 422(1-2), 220-224.18. Tai, WP, & Oh, JH (2002). Preparation and humidity sensing behaviors of nanocrystalline SnO ₂ / TiO ₂ bilayered films. Thin solid films, 422 (1-2), 220-224.

19. Zhu, Y., Chen, J., Li, H., Zhu, Y., & Xu, J. (2014). Synthesis of mesoporous SnO₂-SiO₂composites and their application as quartz crystal microbalance humidity sensor. Sensors and Actuators B: Chemical, 193, 320-325.19. Zhu, Y., Chen, J., Li, H., Zhu, Y., & Xu, J. (2014). Synthesis of mesoporous SnO ₂ -SiO ₂ composites and their application as quartz crystal microbalance humidity sensor. Sensors and Actuators B: Chemical, 193, 320-325.

20. Toloman, D., Popa, A., Stan, M., Socaci, C., Biris, A. R., Katona, G., ... & lacomi, F. (2017). Reduced graphene oxide decorated with Fe doped SnO₂ nanoparticles for humidity sensor. Applied Surface Science, 402, 410-417.20. Toloman, D., Popa, A., Stan, M., Socaci, C., Biris, AR, Katona, G., ... & lacomi, F. (2017). Reduced graphene oxide decorated with Fe doped SnO ₂ nanoparticles for humidity sensor. Applied Surface Science, 402, 410-417.

21. Zhang, D., Sun, Y. E., Li, P., & Zhang, Y. (2016). Facile fabrication of MoS₂-modified SnO₂ hybrid nanocomposite for ultrasensitive humidity sensing. ACS Applied Materials & Interfaces, 8(22), 14142-14149.21. Zhang, D., Sun, YE, Li, P., & Zhang, Y. (2016). Easy fabrication of MoS ₂ -modified SnO ₂ hybrid nanocomposite for ultrasensitive humidity sensing. ACS Applied Materials & Interfaces, 8 (22), 14142-14149.

22. Li, L., Yu, K., Wu, J., Wang, Y., & Zhu, Z. (2010). Structure and humidity sensing properties of SnO₂ zigzag belts. Crystal Research and Technology, 45(5), 539-544.22. Li, L., Yu, K., Wu, J., Wang, Y., & Zhu, Z. (2010). Structure and humidity sensing properties of SnO ₂ zigzag belts. Crystal Research and Technology, 45 (5), 539-544.

23. Ansari, S. G., Ansari, Z. A., Kadam, M. R., Karekar, R. N., & Aiyer, R. C. (1994). The effect of humidity on an SnO₂ thick-film planar resistor. Sensors and Actuators B: Chemical, 21(3), 159-163.23. Ansari, SG, Ansari, ZA, Kadam, MR, Karekar, RN, & Aiyer, RC (1994). The effect of humidity on an SnO ₂ thick-film planar resistor. Sensors and Actuators B: Chemical, 21 (3), 159-163.

24. Tomer, V. K., & Duhan, S. (2015). In-situ synthesis of SnO₂/SBA-15 hybrid nanocomposite as highly efficient humidity sensor. Sensors and Actuators B: Chemical, 212, 517-525.24. Tomer, VK, & Duhan, S. (2015). In-situ synthesis of SnO ₂ / SBA-15 hybrid nanocomposite as highly efficient humidity sensor. Sensors and Actuators B: Chemical, 212, 517-525.

25. Yadav, B. C., Verma, N., & Singh, S. (2012). Nanocrystalline SnO₂-TiO₂ thin film deposited on base of equilateral prism as an opto-electronic humidity sensor. Optics & Laser Technology, 44(6), 1681-1688.25. Yadav, BC, Verma, N., & Singh, S. (2012). Nanocrystalline SnO ₂ -TiO ₂ thin film deposited on the basis of equilateral prism as an opto-electronic humidity sensor. Optics & Laser Technology, 44 (6), 1681-1688.

26. Anbia, M., & Fard, S. E. M. (2011). Improving humidity sensing properties of nanoporous TiO₂-10 mol% SnO₂ thin film by co-doping with La³⁺ and K⁺. Sensors and Actuators B: Chemical, 160(1), 215-221.26. Anbia, M., & Fard, SEM (2011). Improving humidity sensing properties of nanoporous TiO ₂ -10 mol% SnO ₂ thin film by co-doping with La ³⁺ and K ⁺ . Sensors and Actuators B: Chemical, 160 (1), 215-221.

27. Karthick, S., Lee, H. S., Kwon, S. J., Natarajan, R., & Saraswathy, V. (2016). Standardization, calibration, and evaluation of tantalum-nano rGO-SnO₂ composite as a possible candidate material in humidity sensors. Sensors, 16(12), 2079.27. Karthick, S., Lee, HS, Kwon, SJ, Natarajan, R., & Saraswathy, V. (2016). Standardization, calibration, and evaluation of tantalum-nano rGO-SnO ₂ composite as a possible candidate material in humidity sensors. Sensors, 16 (12), 2079.

28. lijima, S., &Ichihashi, T. (1993). Single-shell carbon nanotubes of 1-nm diameter. Nature, 363(6430), 603.28. lijima, S., & Ichihashi, T. (1993). Single-shell carbon nanotubes of 1-nm diameter. Nature, 363 (6430), 603.

29. Serban, B. C., Bumbac, M., Buiu, O., Cobianu, C., Brezeanu, M., &Nicolescu, C. (2018). Carbon nanohoms and their nanocomposites: Synthesis, properties and applications. A concise review. Ann. Acad. Rom. Sci. Ser. Math. Appl, 11, 5-18.29. Serban, B. C., Bumbac, M., Buiu, O., Cobianu, C., Brezeanu, M., & Nicolescu, C. (2018). Carbon nanohoms and their nanocomposites: Synthesis, properties and applications. A concise review. Ann. Acad. Rom. Ski. Ser. Math. Appl, 11, 5-18.

30. Zhu, S., & Xu, G. (2010). Single-walled carbon nanohorns and their applications. Nanoscale, 2(12), 2538-2549.30. Zhu, S., & Xu, G. (2010). Single-walled carbon nanohorns and their applications. Nanoscale, 2 (12), 2538-2549.

31. Pagona, G., Tagmatarchis, N., Fan, J., Yudasaka, M., &Iijima, S. (2006). Cone-end functionalization of carbon nanohoms. Chemistry of Materials, 18()1), 3918-3920.31. Pagona, G., Tagmatarchis, N., Fan, J., Yudasaka, M., & Iijima, S. (2006). Cone-end functionalization of carbon nanohoms. Chemistry of Materials, 18 (1), 3918-3920.

32. Șerban, B. C., Buiu, O., Cobianu, C., Avramescu, V., Dumbrăvescu, N., Brezeanu, M., ... & Marinescu, R. (2019). Temary Carbon-Based Nanocomposite as Sensing Layer for Resistive Humidity Sensor. Multidisciplinary Digital Publishing Institute Proceedings, 29(1), 114.32. Șerban, B. C., Buiu, O., Cobianu, C., Avramescu, V., Dumbrăvescu, N., Brezeanu, M., ... & Marinescu, R. (2019). Temary Carbon-Based Nanocomposite as Sensing Layer for Resistive Humidity Sensor. Multidisciplinary Digital Publishing Institute Proceedings, 29 (1), 114.

33. Serban, B. C., Buiu, O., Dumbrăvescu, N., Cobianu, C., Avramescu, V., Brezeanu, M., ... & Nicolescu, C. M. (2020). Oxidized Carbon Nanohoms as Novei Sensing Layer for Resistive Humidity Sensor. Acta Chimica Slovenica.33. Serban, B. C., Buiu, O., Dumbrăvescu, N., Cobianu, C., Avramescu, V., Brezeanu, M., ... & Nicolescu, C. M. (2020). Oxidized Carbon Nanohoms as New Sensing Layer for Resistive Humidity Sensor. Slovenian Chemical Act.

34. Ugarte, D. (1992). Curling and closure of graphitic networks under electron-beam irradiation. Nature, 359 (6397), 707 - 709.34. Ugarte, D. (1992). Curling and closure of graphitic networks under electron-beam irradiation. Nature, 359 (6397), 707-709.

35. Bartelmess J, Giordani S. Carbon nano-onions (multilayer fullerenes): Chemistry and applications. BeilsteinJ Nanotechnol. 2014;5:1980-8.35. Bartelmess J, Giordani S. Carbon nano-onions (multilayer fullerenes): Chemistry and applications. BeilsteinJ Nanotechnol. 2014; 5: 1980-8.

36. Mohapatra, J., Ananthoju, B., Nair, V., Mitra, A., Bahadur, D., Medhekar, N. V., & Aslam, M. (2018). Enzymatic and non-enzymatic electrochemical glucose sensor based on carbon nano-onions. AppliedSurface Science, 442, 332-341.36. Mohapatra, J., Ananthoju, B., Nair, V., Mitra, A., Bahadur, D., Medhekar, N. V., & Aslam, M. (2018). Enzymatic and non-enzymatic electrochemical glucose sensor based on carbon nano-onions. AppliedSurface Science, 442, 332-341.

37. Breczko, J., Plonska-Brzezinska, Μ. E., & Echegoyen, L. (2012). Electrochemical oxidation and determination of dopamine in the presence of uric and ascorbic acids using a carbon nano-onion and poly (diallyldimethylammonium chloride) composite. Electrochimica Acta, 72, 61 -67.37. Breczko, J., Plonska-Brzezinska,. E., & Echegoyen, L. (2012). Electrochemical oxidation and determination of dopamine in the presence of uric and ascorbic acids using a carbon nano-onion and poly (diallyldimethylammonium chloride) composite. Electrochemistry Act, 72, 61 -67.

38. Bartolome, J. P., Echegoyen, L., & Fragoso, A. (2015). Reactive carbon nano-onion modified glassy carbon surfaces as DNA sensors for human papiilomavirus oncogene detection with enhanced sensitivity. Analytical Chemistry, 87(13), 6744-6751.38. Bartolome, J. P., Echegoyen, L., & Fragoso, A. (2015). Reactive carbon nano-onion modified glassy carbon surfaces as DNA sensors for human papiilomavirus oncogene detection with enhanced sensitivity. Analytical Chemistry, 87 (13), 6744-6751.

Claims

demand

1. Resistive relative humidity monitoring sensor, characterized in that it consists of a dielectric substrate, metal electrodes and a sensitive layer consisting of a thin film of ternary nanocomposite such as oxidized carbon nanowires / SnO ₂ / polyvinylpyrrolidone or oxidized nanocarbon materials onion / SnO2 / polyvinylpyrrolidone type.

The ternary mixture consisting of oxidized carbon nanoworms / SnO2 / polyvinylpyrrolidone, used under the conditions of claim 1, is characterized in that it contains oxidized carbon nanoworms in a mass percentage of 50%, SnO2 and polyvinylpyrrolidone being in equimal proportions.

The ternary mixture of oxidized nanocarbon materials such as onion SnO2 / polyvinylpyrrolidone, used under the conditions of claim 1, is characterized in that it contains oxidized nanocarbon materials of onion type in a mass percentage of 50%, SnO2 and polyvinylpyrrolidone being in eccentric proportions.

4. The dielectric substrate is characterized in that it can be constructed of Si / SiO ₂ , glass, polyimide and can have a thickness between 50 microns and 5 millimeters.

5. The electrodes used are characterized in that they are deposited on the surface of the dielectric substrate by direct printing, sputtering or evaporation.

6. The electrodes used are characterized in that they can be made of the same material (aluminum, chromium, copper, gold) or of different materials.

7. The electrodes used are characterized in that they can be linear or have an interdigitated configuration.

8. The deposition of the sensitive layer consisting of oxidized carbon nanowires / SnO ₂ / polyvinylpyrrolidone, is characterized by the fact that it is made of ethyl alcohol solution by the "drop casting" method on the Si / SiO ₂ substrate with linear electrodes.

9. The deposition of the sensitive layer consisting of oxidized carbon nanoworms / SnO ₂ / polyvinylpyrrolidone is characterized by the fact that it is made of isopropyl alcohol solution by the "drop casting" method on the Si / SiO ₂ substrate with interdigitated electrodes.

10. The deposition of the sensitive layer consisting of oxidized nanocarbon materials such as onion / SnO ₂ / polyvinylpyrrolidone, is characterized by the fact that it is made of ethyl alcohol solution by the "drop casting" method on the Si / SiO ₂ substrate with linear electrodes.

11. The deposition of the sensitive layer consisting of oxidized nanocarbon materials such as onion / SnO2 / polyvinylpyrrolidone is characterized by the fact that it is made of isopropyl alcohol solution by the "drop casting" method on the Si / SiO2 substrate with interdigitated electrodes.

The use of resistive sensors obtained under the conditions of claims 8-11 for humidity monitoring is characterized by the application of a constant current between two electrodes and the measurement of the electrical voltage passing through the sensitive layer at various values of relative humidity.