SnO<sub>2</sub> Nanoribbons as NO<sub>2</sub> Sensors:  Insights from First Principles Calculations

Maiti, Amitesh; Rodríguez, José Antonio; Law, Matt; Kung, Paul; Mckinney, Juan R.; Yang, Peidong

doi:10.1021/nl034235v

Cited by 186 publications

(133 citation statements)

References 18 publications

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“…The surface species for adsorption of NO 2 on SnO 2 are consistent with the findings of Maiti et al, [23] which were extended towards their control under electric fields. We observed a strong dependence of adsorption/desorption of NO 3 species on electric field, with almost on/off characteristics.…”

Section: Discussionsupporting

confidence: 89%

“…The N 1s photoelectron signal showed peaks at binding energies of 406 and 408 eV, related to chemisorbed NO 2 and NO 3 , respectively. [23][24][25] The peaks at 400 and 399 eV are associated with SnÀ NO ad and nitrogen replacing oxygen in the crystal lattice. [26][27][28] The latter peaks around 400 eV appear after exposure of freshly prepared films to NO 2 and remain stable for days, in contrast to the peaks of NO 2 and NO 3 .…”

Section: X-ray Photoelectron Spectroscopic (Xps) Measurementsmentioning

confidence: 99%

“…[17,18] Similar reasoning suggested the use of NO 2 for test reactions. [19][20][21][22][23] During and after exposure to high electric fields, chemical analysis of adsorbates and characterization of the underlying semiconductor were performed, and both measurements are discussed on the basis of an extended Wolkenstein model.…”

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confidence: 99%

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Direct Observation of the Electroadsorptive Effect on Ultrathin Films for Microsensor and Catalytic‐Surface Control

et al. 2013

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Microchemical sensors and catalytic reactors make use of gases during adsorption in specific ways on selected materials. Fine-tuning is normally achieved by morphological control and material doping. The latter relates surface properties to the electronic structure of the bulk, and this suggests the possibility of electronic control. Although unusual for catalytic surfaces, such phenomena are sometimes reported for microsensors, but with little understanding of the underlying mechanisms. Herein, direct observation of the electroadsorptive effect by a combination of X-ray photoelectron spectroscopy and conductivity analysis on nanometre-thick semiconductor films on buried control electrodes is reported. For the SnO2/NO2 model system, NO3 surface species, which normally decay at the latest within minutes, can be kept stable for 1.5 h with a high coverage of 15% under appropriate electric fields. This includes uncharged states, too, and implies that nanoelectronic structures provide control over the predominant adsorbate conformation on exterior surfaces and thus opens the field for chemically reactive interfaces with in situ tunability.

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Section: Discussionsupporting

confidence: 89%

Section: X-ray Photoelectron Spectroscopic (Xps) Measurementsmentioning

confidence: 99%

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Direct Observation of the Electroadsorptive Effect on Ultrathin Films for Microsensor and Catalytic‐Surface Control

et al. 2013

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“…In particular, it is widely used as solid state chemical sensors to both oxidizing (e.g., CO 2 , NO 2 ) and reducing (CO, NO) gases [3][4][5][6][7][8][9][10][11][12]. In all these applications, the key for governing device functionality is the properties of SnO 2 surface or its interface with functional organic molecules.…”

Section: Introductionmentioning

confidence: 99%

Ab initio thermodynamic study of the SnO₂(110) surface in an O₂ and NO environment: a fundamental understanding of the gas sensing mechanism for NO and NO₂

Hong

Kye

et al. 2016

Phys. Chem. Chem. Phys.

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For the purpose of elucidating the gas sensing mechanism of SnO 2 for NO and NO 2 gases, we calculate the phase diagram of SnO 2 (110) surface in contact with an O 2 and NO gas environment by means of ab initio thermodynamic method. Firstly we build a range of surface slab models of oxygen pre-adsorbed SnO 2 (110) surfaces using (1×1) and (2×1) surface unit cells and calculate their Gibbs free energies considering only oxygen chemical potential. The fully reduced surface containing the bridging and in-plane oxygen vacancies in the oxygen-poor condition, while the fully oxidized surface containing the bridging oxygen and oxygen dimer in the oxygen-rich condition, and the stoichiometric surface in between, were proved to be most stable. Using the selected plausible NO-adsorbed surfaces, we then determine the surface phase diagram of SnO 2 (110) surfaces in (∆µ O , ∆µ NO ) space. In the NO-rich condition, the most stable surfaces were those formed by NO adsorption on the most stable surfaces in contact with only oxygen gas. Through the analysis of electronic charge transferring and density of states during NO x adsorption on the surface, we provide a meaningful understanding about the gas sensing mechanism.

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“…However, such conclusion is based on the assumption that the molecule has a stable adsorbed structure on the SWNT at room temperature, which would be possible if the SWNT-molecule binding is strong enough. For NO 2 one could explain such stability through the formation of NO 3 [6], a common feature observed on metal-oxide surfaces [7] and nanowires as well [8]. However, several calculations for NH 3 have yielded only very weak binding and very small charge transfer [2,[9][10][11].…”

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confidence: 99%

Nanotube-based gas sensors – Role of structural defects

Andzelm¹,

Govind²,

Maiti

2006

Chemical Physics Letters

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138

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Existing theoretical literature suggests that defect-free, pristine carbon nanotubes (CNTs) interact weakly with many gas molecules like H 2 O, CO, NH 3 , H 2 , and so on. The case of NH 3 is particularly intriguing because this is in disagreement with experimentally observed changes in electrical conductance of CNTs upon exposure to these gases. In order to explain such discrepancy, we have carried out Density Functional Theory (DFT) investigations of the role of common atomistic defects in CNT (Stone-Wales, monovacancy, and interstitial) on the chemisorption of NH 3 . Computed binding energies, charge transfer, dissociation barriers, and vibrational modes are compared with existing experimental results on electrical conductance, thermal desorption and infrared spectroscopy. PACS: 61.46.+w, 85.35 [2,[9][10][11]. This is in disagreement not only with the observed drop in electrical conductance at room temperature, but also with recent temperature-programmed-desorption (TPD) measurements [12], which shows that most of the gas desorbs only at elevated temperatures (500-700 K).A logical resolution to the above problem would be to note that SWNTs are likely to have some defects incorporated either thermally or during high-temperature growth conditions. Also, they are not in isolation, and surrounding environment (oxygen, water vapor), or the substrate, or metal contacts at the ends might directly or indirectly provide a mechanism of binding of the gas molecules. Limited 2 investigations have been made on the effect of metal contacts, especially in connection with O 2 adsorption [13,14]. However, NH 3 adsorption appears to occur along the whole length of the tube [1], which suggests either topological defects on the tube itself, or an indirect mechanism due to involvement of solvents or the substrate.In this Letter, we investigate the role of three types of topological defects commonly considered for SWNTs and graphene sheet, i.e., a Stone-Wales (SW) defect [15] (i.e. a 5775 defect formed by bondrotation), a monovacancy (i.e. missing a C-atom), and an insterstitial (i.e. an extra bridging C). The presence of such geometric defects has recently been confirmed experimentally [16]. As a concrete model of s-SWNT, we chose the (8, 0) SWNT. All the defect and chemisorbed structures were created by suitably modifying the original defect-free tube (Fig. 1a). In order to speed up our calculations the initial structures were minimized with the COMPASS forcefield [17], followed by further relaxation with the DFT code (Fig. 1d); (ii) SW2, a chiral Stone-Wales defect (Fig. 1f); (iii) a monovacancy (V) (Fig. 1b); and (iv) an interstitial (I) (Fig. 1c). It also considers the situation in which an O 2 molecule has dissociated over a SW1 (Fig. 1e) [24]. Table 1 lists the respective DMol 3 -computed formation energies of these defects for supercells of two sizes, i.e., two and four times the smallest periodic segment of the (8, Table 1, we note that SW1 is energetically more stable than SW2, and is therefore the only SW d...

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SnO₂ Nanoribbons as NO₂ Sensors: Insights from First Principles Calculations

Cited by 186 publications

References 18 publications

Direct Observation of the Electroadsorptive Effect on Ultrathin Films for Microsensor and Catalytic‐Surface Control

Direct Observation of the Electroadsorptive Effect on Ultrathin Films for Microsensor and Catalytic‐Surface Control

Ab initio thermodynamic study of the SnO₂(110) surface in an O₂ and NO environment: a fundamental understanding of the gas sensing mechanism for NO and NO₂

Nanotube-based gas sensors – Role of structural defects

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SnO2 Nanoribbons as NO2 Sensors: Insights from First Principles Calculations

Cited by 186 publications

References 18 publications

Direct Observation of the Electroadsorptive Effect on Ultrathin Films for Microsensor and Catalytic‐Surface Control

Direct Observation of the Electroadsorptive Effect on Ultrathin Films for Microsensor and Catalytic‐Surface Control

Ab initio thermodynamic study of the SnO2(110) surface in an O2 and NO environment: a fundamental understanding of the gas sensing mechanism for NO and NO2

Nanotube-based gas sensors – Role of structural defects

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Product

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SnO₂ Nanoribbons as NO₂ Sensors: Insights from First Principles Calculations

Ab initio thermodynamic study of the SnO₂(110) surface in an O₂ and NO environment: a fundamental understanding of the gas sensing mechanism for NO and NO₂