On mechanism of NO2 detection by ZnO excitonic luminescence

Orabona, Emanuele; Pallotti, Deborah Katia; Fioravanti, Ambra; Gherardi, S.; Sacerdoti, M.; Carotta, M.C.; Maddalena, P.; Lettieri, S.

doi:10.1016/j.snb.2015.01.022

Cited by 12 publications

(16 citation statements)

References 30 publications

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“…[13][14][15][16][17][18][19][20][21][22][23] Unfortunately, approaches based on intensity measurement of the PL emission are also prone to errors. In particular, fluctuations in the excitation light intensity can hinder the understanding of the experimental data when real-time monitoring is performed and small integration times in the PL measurement have to be used.…”

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confidence: 99%

Unconventional ratiometric-enhanced optical sensing of oxygen by mixed-phase TiO2

Lettieri

Pallotti

Gesuele

et al. 2016

Applied Physics Letters

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Abstract. We show that mixed-phase titanium dioxide (TiO2) can be effectively employed as an unconventional, inorganic, dual-emitting and ratiometric optical sensor of O2. Simultaneous availability of rutile and anatase TiO2 PL and their peculiar "anti-correlated" PL responses to O2 allow using their ratio as measurement parameter associated to O2 concentration, leading to an experimental responsivity being by construction larger than the one obtainable for single-phase PL detection. A proof of this concept in given, showing a two-fold enhancement of the optical responsivity provided by the ratiometric approach. Besides the peculiar ratiometric-enhanced responsivity, other characteristics of mixed phase TiO2 can be envisaged as favorable for O2 optical probing, namely: a) low production costs, b) absence of heterogeneous components, c) self-supporting properties. These characteristics encourage experimenting its use for applications requiring high indicator quantities at competitive price, possibly also tackling the need to develop supporting matrixes that carry the luminescent probes and avoiding issues related to the use of different components for ratiometric sensing.Determining the content of molecular oxygen (O2) in gas mixtures and/or aqueous environments is important in many different fields. For example, monitoring the O2 concentration in the exhaust stream of an internal combustion engine provides information on the air-fuel ratio of the combustion process, whose control is relevant for reducing harmful emission [1][2][3] . Knowing the concentration of O2 dissolved in water (also "dissolved oxygen", DO) is also crucial in many applications. DO level is intimately related to the state of health of marine habitats, to the concentration of organic pollutants in water 4 and is of great importance for biological studies. In fact, DO content in cell culture media affects cell growth rate, metabolism and protein synthesis, exerting a decisive influence on the cellular functions and behaviors. To mention a few examples, hypoxia/re-oxygenation induce stem cell like

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confidence: 99%

Unconventional ratiometric-enhanced optical sensing of oxygen by mixed-phase TiO2

Lettieri

Pallotti

Gesuele

et al. 2016

Applied Physics Letters

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“…Zinc oxide (ZnO) has already been utilized in gas sensors for detecting toxic or hazardous gases [54][55][56][57]. To enhance the sensitivity and response time of NOx sensors, ZnO was always combined with other materials.…”

Section: Semiconductor Oxides Based Gas Sensormentioning

confidence: 99%

Development of NO<sub>x</sub> Emission and Electrochemical Detection in Atmosphere

Sun

Wei

2016

Preprint

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Reactive NOx is one of the major air pollutants, which also plays a key role as greenhouse gas. Many research efforts have been devoted to not only detection of NOx in air but also abatement of NOx emission. The aim of this mini review is to provide a panoramic snapshot of the electrochemical analysis methods for the emission and detection of NOx in atmosphere, with special emphasis on NOx sensor. The electrochemical detecting mechanism and materials for fabricating electrochemical gas sensors are discussed and the prospects and challenges in this area are also evaluated. This work will serve as a useful source to inform the interested audience of the latest developments and applications in the field of NOx emission and electrochemical detection.

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“…To prepare the set of MOX gas sensors, suitable to detect the analytes’ concentrations in the oil headspace, materials typically used in the fabrication of gas sensors [ 26 , 27 , 28 , 29 , 30 , 31 ] were initially considered, including TiO 2 , SnO 2 , WO 3 , and ZnO. Concerning ZnO, three different morphologies (nanoparticles aggregates in the form of leaves, long needles, and hexagonal prisms) were considered because the control of the morphology of nanosized metal oxide semiconductors can improve the selectivity toward various gases [ 32 , 33 ]. In addition, a mixed oxide (LaFeO 3 ) and (Ti,Sn) solid solutions were synthesized because of their wide potential of combining the advantages and weakening the disadvantages of the single component [ 34 ].…”

Section: Introductionmentioning

confidence: 99%

(Ti,Sn) Solid Solution Based Gas Sensors for New Monitoring of Hydraulic Oil Degradation

Fioravanti¹,

Marani²,

Massarotti

et al. 2021

Materials

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The proper operation of a fluid power system in terms of efficiency and reliability is directly related to the fluid state; therefore, the monitoring of fluid ageing in real time is fundamental to prevent machine failures. For this aim, an innovative methodology based on fluid vapor analysis through metal oxide (shortened: MOX) gas sensors has been developed. Two apparatuses were designed and realized: (i) a dedicated test bench to fast-age the fluid under controlled conditions; (ii) a laboratory MOX sensor system to test the headspace of the aged fluid samples. To prepare the set of MOX gas sensors suitable to detect the analytes’ concentrations in the fluid headspace, different functional materials were synthesized in the form of nanopowders, characterizing them by electron microscopy and X-ray diffraction. The powders were deposited through screen-printing technology, realizing thick-film gas sensors on which dynamical responses in the presence of the fluid headspace were obtained. It resulted that gas sensors based on solid solution TixSn1–xO2 with x = 0.9 and 0.5 offered the best responses toward the fluid headspace with lower response and recovery times. Furthermore, a decrease in the responses (for all sensors) with fluid ageing was observed.

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On mechanism of NO2 detection by ZnO excitonic luminescence

Cited by 12 publications

References 30 publications

Unconventional ratiometric-enhanced optical sensing of oxygen by mixed-phase TiO2

Unconventional ratiometric-enhanced optical sensing of oxygen by mixed-phase TiO2

Development of NO<sub>x</sub> Emission and Electrochemical Detection in Atmosphere

(Ti,Sn) Solid Solution Based Gas Sensors for New Monitoring of Hydraulic Oil Degradation

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