Influence of the doping method on the sensitivity of Pt-doped screen-printed SnO2 sensors

Bittencourt, Carla; Llobet, Eduard; Ivanov, P.; Correig, X.; Vilanova, X; Brezmes, J.; Hubálek, Jaromír; Malysz, K.; Pireaux, Jean‐Jacques; Calderer, J.

doi:10.1016/s0925-4005(03)00648-8

Cited by 52 publications

(34 citation statements)

References 16 publications

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“…The favorable neck size (i.e., below twice the Debye length) at low SiO 2 content leads to exceptionally high sensitivity, which is preserved by the high thermal stability of the Si-doped SnO 2 crystals. The response of our 2.5 wt % SiO 2 -doped sensor to 10 ppm EtOH at about 300 8C is 2-10 times higher than that of pure SnO 2 [23,[34][35][36] (even at higher EtOH concentrations) and 8-fold that of commercial sensors such as TGS 822. [34] The highest response at 300 and 400 8C of Ag-doped SnO 2 sensors [4] to 1000 ppm EtOH is 22-40, respectively, while that of the present 2.5 wt % SiO 2 -doped one to 50 ppm (1/20th of their [4] concentration) is 318, corresponding to 14-8 times improvement, respectively.…”

Section: Sensor Performancementioning

confidence: 93%

Optimal Doping for Enhanced SnO₂ Sensitivity and Thermal Stability

Tricoli

Gräf

Pratsinis

2008

Adv Funct Materials

196

179

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Tin oxide nanocrystals (5–10 nm) doped with silica (0–15 wt %) were made by flame‐spray‐pyrolysis direct deposition onto the sensing electrodes and in situ stabilization by rapid flame annealing. Although increased SiO2‐doping reduced the SnO2 crystal and grain size, its sensing performance to ethanol vapor (0.1–50 ppm) exhibited an optimum with respect to SiO2 content. The thermal stability and morphology of SiO2‐doped SnO2 nanoparticles were evaluated by sintering at 200–900 °C for 4–24 h in air. At low SiO2 content, sintering of SnO2 was prevented only partially resulting in small sinter necks (bottlenecks) between SnO2 primary particles (smaller than twice the Debye length). This morphology drastically enhanced the sensitivity toward the analyte by maintaining a thermally stable high surface area and fully depleted connections at the primary particle necks. This enhancement is attributed mostly to the decreasing neck size of the SnO2SiO2 heterojunctions rather than the decreasing SnO2 crystallite and grain sizes with increasing SiO2 doping. At high SiO2 contents, SnO2 sintering was inhibited as its grains were separated effectively by dielectric SiO2; this resulted in isolated SnO2 nanocrystals with drastically reduced sensitivity, thereby effectively being insulators.

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Section: Sensor Performancementioning

confidence: 93%

Optimal Doping for Enhanced SnO₂ Sensitivity and Thermal Stability

Tricoli

Gräf

Pratsinis

2008

Adv Funct Materials

196

179

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“…[3,26,28] Thus, the lower limit of detection and sensitivity were improved by the use of nanostructured materials with grain sizes comparable to twice their Debye length. [29][30][31][32] Finely dispersing catalyst nanoparticles, such as Pt, [33][34][35] Pd, [33,36,37] Ag, [38,39] Ru, [40] and Au [41,42] on the metal oxide surface, further increased the sensitivity, mainly by spillover effects. Nevertheless, the long-term stability at the operating temperature (typically 250-600 8C) of these highly sensitive materials composed of oxide [30,32,43] and dopant [41,44] components is still challenging.…”

Section: Introductionmentioning

confidence: 99%

Semiconductor Gas Sensors: Dry Synthesis and Application

2010

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Since the development of the first chemoresistive metal oxide based gas sensors, transducers with innovative properties have been prepared by a variety of wet- and dry-deposition methods. Among these, direct assembly of nanostructured films from the gas phase promises simple fabrication and control and with the appropriate synthesis and deposition methods nm to μm thick films, can be prepared. Dense structures are achieved by tuning chemical or vapor deposition methods whereas particulate films are obtained by deposition of airborne, mono- or polydisperse, aggregated or agglomerated nanoparticles. Innovative materials in non-equilibrium or sub-stoichiometric states are captured by rapid cooling during their synthesis. This Review presents some of the most common chemical and vapor-deposition methods for the synthesis of semiconductor metal oxide based detectors for chemical gas sensors. In addition, the synthesis of highly porous films by novel aerosol methods is discussed. A direct comparison of structural and chemical properties with sensing performance is given.

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“…Microsensors are particularly attractive for measurements in the low concentration range while higher CO concentrations may lead to a baseline drifts owing to the strong interaction between CO and Pt/doped SnO 2 . [20] The high material resistance is a consequence of the low thermal conductivity of the ''as-deposited'' layer, so that a sharp temperature drop occurs toward its outer surface. This temperature drop dramatically decreases the layer electrical conductivity.…”

mentioning

confidence: 99%