A study on the sensing of NO2 and O2 utilizing ZnO films grown by aerosol spray pyrolysis

Mhlongo, G.H.; Motaung, D.E.; Kortidis, Ioannis; Mathe, Ntombi; Ntwaeaborwa, O.M.; Swart, H.C.; Mwakikunga, Bonex W.; Ray, Sirsendu Sekhar; Kiriakidis, G.

doi:10.1016/j.matchemphys.2015.06.036

Cited by 22 publications

(7 citation statements)

References 66 publications

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“…However, despite the research progress that has been made to demonstrate the advantages of SMOs as building blocks for gas sensors, a number of challenges remain in terms of attaining high sensitivity, low detection limits, fast response and recovery times, and a cross-sensitivity to humid atmospheres since an enhancement in sensitivity alone does not fulfil all of the ideal sensor requirements. Among the various SMOs examined to date, ZnO is the most frequently utilised n-type semiconductor material for gas sensing owing to its good chemical stability, which results in an excellent sensing capability for the detection of various pollutant/hazardous gases, such as hydrogen sulpfide, carbon monoxide, methane, and ammonia (NH 3 ) 6–11 . Among these environmentally hazardous gases, NH 3 is a highly toxic gas with a characteristic pungent smell.…”

Section: Introductionmentioning

confidence: 99%

A highly responsive NH3 sensor based on Pd-loaded ZnO nanoparticles prepared via a chemical precipitation approach

Mhlongo

Motaung

Cummings

et al. 2019

Sci Rep

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The gas-detecting ability of nanostructured ZnO has led to significant attention being paid to the development of a unique and effective approach to its synthesis. However, its poor sensitivity, cross-sensitivity to humidity, long response/recovery times and poor selectivity hinder its practical use in environmental and health monitoring. In this context, the addition of noble metals, as dopants or catalysts to modify the ZnO surface has been examined to enhance its sensing performance. Herein, we report preparation of Pd-loaded ZnO nanoparticles via a chemical precipitation approach. Various Pd loadings were employed to produce surface-modified ZnO nanostructure sensors, and their resulting NH 3 sensing capabilities both in dry and humid environments were investigated. Through a comparative gas sensing study between the pure and Pd-loaded ZnO sensors upon exposure to NH 3 at an optimal operating temperature of 350 °C, the Pd-loaded ZnO sensors were found to exhibit enhanced sensor responses and fast response/recovery times. The influence of Pd loading and its successful incorporation into ZnO nanostructure was examined by X-ray diffraction, high resolution-transmission electron microscopy, and X-ray photoelectron spectroscopy. XPS studies demonstrated that in all samples, Pd existed in two chemical states, namely Pd° and Pd 2+ . The possible sensing mechanism related to NH 3 gas is also discussed in detail.

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Section: Introductionmentioning

confidence: 99%

A highly responsive NH3 sensor based on Pd-loaded ZnO nanoparticles prepared via a chemical precipitation approach

Mhlongo

Motaung

Cummings

et al. 2019

Sci Rep

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“…17 Among these material ZnO is one of the candidates for detection of NO 2 gas, because of its chemical and thermal stability in the environment of mixtures of various toxic gases. 18 Several advanced methods are available for the synthesis of thin lms used for the gas sensor application such as electron beam lithography and reactive vapor deposition. 19,20 All these techniques demands highly sophisticated instruments with various reaction conditions such as high operating temperature and pressure, hazardous chemicals etc.…”

Section: Introductionmentioning

confidence: 99%

Multifunctional zinc oxide thin films for high-performance UV photodetectors and nitrogen dioxide gas sensors

et al. 2016

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“…In the ZnO film, the peak of Zn 2p 3/2 attributed to the crystalline lattice of zinc oxide is located at 1021.51 eV. [ 69 ] In the case of the AZO‐1 and AZO‐2 films, the Zn 2p 3/2 peak is very similar to the one observed in the ZnO sample with the positions of 1021.7 and 1021.6 eV, respectively. The O 1s XPS spectrum of ZnO ETL was deconvoluted into three peaks with energy levels of 530.2, 531.4, and 532.3 eV, which can be assigned to the lattice of oxygen atom in the Wurtzite structure of ZnO (peak A), the oxygen deficiency (peak B), and the hydroxyl groups on the ZnO surface (peak C), respectively.…”

Section: Resultsmentioning

confidence: 89%

Atomic Layer Engineering of Aluminum‐Doped Zinc Oxide Films for Efficient and Stable Perovskite Solar Cells

Kruszyńska

Ozkaya

Surucu

et al. 2022

Adv Materials Inter

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promising light absorber materials, demon strating low-cost solution processing, ease of fabrication, and outstanding optoelectronic properties. [1,2] Since the first report on the perovskite solar cells (PSCs) employing methylammonium lead iodide (MAPbI 3 ), [3] their power conversion efficiency (PCE) has now exceeded 25% for small-area cells. [4,5] The high efficiency of PSCs is achieved by tuning the perovskite layer through compositional engineering, [6][7][8] surface passivation, [9][10][11][12][13] and/or by using various additives. [14][15][16] Besides component engineering of the perovskite layer, a lot of works have been devoted to the development of efficient charge transport layers. [17][18][19][20][21] Particularly, the electron transport layers (ETLs) play an important role in realizing efficient and stable PSCs. [22,23] Thus far, titanium dioxide (TiO 2 ) is a widely applied ETL in PSCs but it suffers from low conductivity and high surface defect density. [24] Among alternative ETLs, zinc oxide (ZnO) has been regarded as a convenient candidate due to its high electron mobility and well-matched energy level with perovskite material. [25,26] This Atomic layer deposition (ALD) has been considered as an efficient method to deposit high quality and uniform thin films of various electron transport materials for perovskite solar cells (PSCs). Here, the effect of deposition sequence in the ALD process of aluminum-doped zinc oxide (AZO) films on the performance and stability of PSCs is investigated. Particularly, the surface of AZO film is terminated by diethylzinc (DEZ)/H 2 O (AZO-1) or trimethylaluminum (TMA)/H 2 O pulse (AZO-2), and investigated with surface-sensitive X-ray photoelectron spectroscopy technique. It is observed that AZO-2 significantly enhances the thermal stability of the upcoming methylammonium lead iodide (MAPbI 3 ) layer and facilitates charge transport at the interface as evidenced by photoluminescence spectroscopes and favorable interfacial band alignment. Finally, planar-type PSC with AZO-2 layer exhibits a champion power conversion efficiency of 18.09% with negligible hysteresis and retains 82% of the initial efficiency after aging for 100 h under ambient conditions (relative humidity 40 ± 5%). These results highlight the importance of atomic layer engineering for developing efficient and stable PSCs.

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A study on the sensing of NO2 and O2 utilizing ZnO films grown by aerosol spray pyrolysis

Cited by 22 publications

References 66 publications

A highly responsive NH3 sensor based on Pd-loaded ZnO nanoparticles prepared via a chemical precipitation approach

A highly responsive NH3 sensor based on Pd-loaded ZnO nanoparticles prepared via a chemical precipitation approach

Multifunctional zinc oxide thin films for high-performance UV photodetectors and nitrogen dioxide gas sensors

Atomic Layer Engineering of Aluminum‐Doped Zinc Oxide Films for Efficient and Stable Perovskite Solar Cells

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