Effect of noble metal functionalization and film thickness on sensing properties of sprayed TiO2 ultra-thin films

Ababii, Nicolai; Hoppe, M.; Shree, Sindu; Vahl, Alexander; Ulfa, Maria; Pauporté, Thierry; Viana, Bruno; Creţu, Vasilii; Magariu, Nicolae; Postica, Vasile; Sontea, Victor; Terasa, Maik-Ivo; Polonskyi, Oleksandr; Faupel, Franz; Adelung, Rainer; Lupan, Oleg

doi:10.1016/j.sna.2019.04.017

Cited by 21 publications

(35 citation statements)

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“…The TiO2/CuO/Cu2O thin films were decorated with Ag and AgPt alloy nanoparticles (Ag NP and AgPt NP) using a high vacuum deposition system (custom-made) with attached Gas Aggregation Source (GAS, Haberland type [25]). Details of the deposition of noble metal alloy nanoparticles can be found in our earlier work [7,26]. For the preparation of thin film composites with Pd NPs, a similar custom-constructed chamber for deposition under high vacuum and with attached Haberland-type GAS was used [9,11,27] and a technological approach developed by Lupan et al [28].…”

Section: Methodsmentioning

confidence: 99%

“…Previous studies on the decoration of semiconducting metal oxide nanostructures with nanoparticles (NPs), have demonstrated the versatile nature of such combined systems, e.g. in gas, UV and temperature sensors or for the discrimination of volatiles [7][8][9]. For example, a significant increase in sensitivity by a factor of ~ 60 and selectivity towards 200 ppm of ethanol vapors was achieved following surface functionalization of columnar ZnO:Fe films using AgO/Ag nanoparticles [4], which was confirmed by quantum mechanical calculations showing that (AgO)5 clusters change the surface chemistry of the Fe-doped zinc oxide ZnO (10-10) surface towards ethanol detection [4].…”

Section: Introductionmentioning

confidence: 99%

“…An excellent example for the requirement of reliable gas sensors is n-butanol, which is a stimulating and narcotic volatile compound, used extensively as a solvent and extracting agent of organic synthesis intermediates [17]. However, exposure to n-butanol vapours has adverse health effects in humans, causing symptoms like dizziness, headaches, somnolence or dermatitis [7,17,18]. The traditional and most frequently used method for the detection of n-butanol is gas chromatography (GC) [17,19,20], which is a complicated, timeconsuming and costly technique.…”

Section: Introductionmentioning

confidence: 99%

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Tailoring the selectivity of ultralow-power heterojunction gas sensors by noble metal nanoparticle functionalization

et al. 2021

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Heterojunctions are used in solar cells and optoelectronics applications owing to their excellent electrical and structural properties. Recently, these energy-efficient systems have also been employed as sensors to distinguish between individual gases within mixtures. Through a simple and versatile functionalization approach using noble metal nanoparticles, the sensing properties of heterojunctions can be controlled at the nanoscopic scale. This work reports the nanoparticle surface functionalization of the TiO2/CuO/Cu2O mixed oxide heterostructures, where the gas sensing selectivity of the material is tuned to achieve versatile sensors with ultra-low power consumption. Functionalization with Ag or AgPt-nanoclusters (5-15 nm diameter), changed the selectivity from ethanol to butanol vapour. The Pdnanocluster functionalization shifts the selectivity from the alcohols to hydrogen. The fabricated sensors show excellent low power consumption below 1 nW. To gain insight into the selectivity mechanism, density functional theory (DFT) calculations were carried out to simulate the adsorption of H2, C2H5OH and n-C4H9OH at the noble metal nanoparticle decorated ternary heterostructure interface. These calculations also show a decrease in the work function by ~2.6 eV with respect to the pristine ternary heterojunctions. This work lays the foundation for the production of a very versatile array of sensors of ultra-low power consumption with applications for the detection of individual gases in a mixture.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Tailoring the selectivity of ultralow-power heterojunction gas sensors by noble metal nanoparticle functionalization

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“…Jones is higher than that (1.07 × 10 11 ) of ZnO based device, demonstrates the high performance of photodetection under a weak light condition [38][39][40][41]. Notably, our photodetector proves as superior as detectivity and responsivity of traditional UV detectors and excellent external quantum efficiency exceed 60%.…”

Section: Uv Photoresponse Measurementsmentioning

confidence: 86%

Photodetectors for weak signal conditions from Au/Cu co-doped ZnO

et al. 2021

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Here, we have used a simple method for polyol synthesis, analysis, and testing of Au/Cudoped ZnO Ultraviolet (UV) photodetectors (PD). Our results are reported and discussed by X-ray diffraction (XRD) to ensure that the manufactured samples show a hexagonal wurtzite ZnO structure. Transmission electron microscopy (TEM) confirmed the nanoparticle growth in the hexagonal sample on the surface, which is the key to improving the light response. Our prepared UV PD Au/Cu codoped ZnO showed a rapid time at a power density of 7.6 mW. the highest responsivity of R= 575 mA/W and sensitivity 10 3 obtained at 7.6 mW with an applied voltage of 1V. Our results demonstrate the obvious substitution of Au and Cu in ZnO, thereby improving the UV-sensing light response.

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“…Due to the heat treatment, it is possible that the Na diffuses to the surface. [28] The C peak originates from adsorbed atmospheric hydrocarbons. [28,29] For a detailed XPS analysis, the C-1s, Si-2p, and Zn-2p were measured with a high resolution.…”

Section: Characterization Of Sio 2 -Covered Zno Columnar Filmsmentioning

confidence: 99%

Improved Long‐Term Stability and Reduced Humidity Effect in Gas Sensing: SiO₂ Ultra‐Thin Layered ZnO Columnar Films

Postica

Lupan

Gapeeva

et al. 2021

Adv Materials Technologies

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The undoped and metal‐doped zinc oxide columnar films (ZnO:Sn, ZnO:Fe, ZnO:Ag, and ZnO:Cu) are covered with an ultra‐thin layer of SiO2 (10–20 nm). The electrical, UV, and volatile organic compounds (VOCs) sensing properties are evaluated under different ambient conditions for ≈7 months to investigate the impact of the top SiO2‐layer on the long‐term stability of samples. The obtained results show a high immunity of sensing properties of SiO2‐coated samples to humidity. Furthermore, gas sensing measurements show that the loss in response after 203 days is significantly lower for coated samples indicating higher stability of sensing performance. For ZnO:Fe the gas response is reduced by about 90% after 203 days, but for SiO2‐coated ZnO:Fe columnar films the gas response is slightly reduced by only 38%. The density functional theory (DFT) calculations show that water species bind strongly with the surface SiO2 layer atoms with a −0.129 e− charge transfer, which is, much higher compared to the interaction with ethanol and acetone. Calculations show strong binding of water species on the SiO2 layer indicating preferential absorption of water molecules on SiO2. The obtained results demonstrate an important role of the top SiO2 ultra‐thin layer in order to produce humidity‐tolerant sensitive devices.

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Effect of noble metal functionalization and film thickness on sensing properties of sprayed TiO2 ultra-thin films

Cited by 21 publications

References 83 publications

Tailoring the selectivity of ultralow-power heterojunction gas sensors by noble metal nanoparticle functionalization

Tailoring the selectivity of ultralow-power heterojunction gas sensors by noble metal nanoparticle functionalization

Photodetectors for weak signal conditions from Au/Cu co-doped ZnO

Improved Long‐Term Stability and Reduced Humidity Effect in Gas Sensing: SiO₂ Ultra‐Thin Layered ZnO Columnar Films

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Effect of noble metal functionalization and film thickness on sensing properties of sprayed TiO2 ultra-thin films

Cited by 21 publications

References 83 publications

Tailoring the selectivity of ultralow-power heterojunction gas sensors by noble metal nanoparticle functionalization

Tailoring the selectivity of ultralow-power heterojunction gas sensors by noble metal nanoparticle functionalization

Photodetectors for weak signal conditions from Au/Cu co-doped ZnO

Improved Long‐Term Stability and Reduced Humidity Effect in Gas Sensing: SiO2 Ultra‐Thin Layered ZnO Columnar Films

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Product

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Improved Long‐Term Stability and Reduced Humidity Effect in Gas Sensing: SiO₂ Ultra‐Thin Layered ZnO Columnar Films