SnO2–TiO2 solid solutions for gas sensors

Radecka, M.; Zakrzewska, K.; Rękas, M.

doi:10.1016/s0925-4005(98)00023-9

Cited by 157 publications

(100 citation statements)

References 13 publications

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“…Owing to its high sensitivity to the reducing atmosphere, SnO 2 is the most used oxide as active component of sensor devices. Relatively low thermodynamic stability manifested by its high equilibrium oxygen pressure (SnO 2 ↔ SnO + (1/2)O 2 ) is responsible for the degradation of its electrical properties upon prolonged thermal treatment in reducing gas atmosphere [1]. On the other hand, TiO 2 exhibits much lower equilibrium pressure of oxygen than that of SnO 2 , and consequently, major resistance to the reducing atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Electronic and structural properties of SnxTi1−xO2 solid solutions: a periodic DFT study

et al. 2003

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The structural and electronic properties of selected compositions of Sn x Ti 1−x O 2 solid solutions (x = 0, 1/24, 1/16, 1/12, 1/8, 1/6, 1/4, 1/2, 3/4, 5/6, 7/8, 11/12, 15/16, 23/24 and 1) were investigated by means of periodic density functional theory (DFT) calculations at B3LYP level. The calculations show that the corresponding lattice parameters vary non-linearly with composition, supporting positive deviations from Vegard's law in the Sn x Ti 1−x O 2 system. Our results also account for the fact that chemical decomposition in Sn x Ti 1−x O 2 system is dominated by composition fluctuations along [0 0 1] direction. A nearly continuous evolution of the direct band gap and the Fermi level with the growing value of x is predicted. Ti 3d states dominate the lower portion of the conduction band of Sn x Ti 1−x O 2 solid solutions. Sn substitution for Ti in TiO 2 increases the oxidation-reduction potential of the oxide as well as it renders the lowest energy transition to be indirect. These two effects can be the key factors controlling the rate for the photogenerated electron-hole recombination. These theoretical results are capable to explain the enhancement of photoactivity in Sn x Ti 1−x O 2 solid solutions.

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Section: Introductionmentioning

confidence: 99%

Electronic and structural properties of SnxTi1−xO2 solid solutions: a periodic DFT study

et al. 2003

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“…We used two types of SnO 2 TiO 2 films: (a) rf reactive ion sputtered (RIS) from Ti Sn metallic mosaic targets (see [14]), and (b) deposited by means of electron gun molecular beam (MB) sputtering from SnO 2 and TiO 2 targets. During deposition the substrates were kept at a temperature of 200°C.…”

Section: Methodsmentioning

confidence: 99%

“…The phase analysis of the RIS SnO 2 TiO 2 films performed earlier [14,15,17] show that in the as-deposited state and after annealing, the SnO 2 films display a cassiterite phase, the TiO 2 films are rutile/anatase mixtures and the intermediate compositions are predominantly mixtures of solid solutions based on SnO 2 and TiO 2 compounds as it was shown for bulk ceramic samples annealed at T 800°C [5][6][7][8][9][10]. In this study, the structure of the pure SnO 2 and TiO 2 samples was comparable to that of cassiterite and rutile/anatase, respectively.…”

Section: Xrd Analysis Of Thick ( 200 Nm) Films Deposited On Sio 2 /Simentioning

confidence: 99%

Structural evolution of SnO2TiO2 nanocrystalline films for gas sensors

Edelman

Hahn

Seifried

et al. 2000

Materials Science and Engineering: B

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Thin films (50-200 nm) of SnO 2 TiO 2 were deposited on SiO 2 /(001)Si substrates by RF-sputtering and by molecular beam before they were annealed in vacuum at 200-900°C. In-situ TEM, XRD, SEM, Raman and IR-spectroscopy were used to analyze the structure transformations in the SnO 2 TiO 2 films. In the as-deposited state, the films are amorphous. They crystallize at higher temperatures (starting at about 500°C) forming nanosized grains. The problem of the spinodal decomposition in the SnO 2 TiO 2 system observed earlier at high temperatures is discussed also for low-temperature processing. The stoichiometry of the films of both groups (reactive ion sputtered and high-vacuum e-gun sputtered) is being compared.

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“…Se han realizado recientemente estudios sobre sinterización y transporte de masa en cerámicos policristalinos de (Sn,Ti)O 2 (26), además se trabaja en su potencial uso como sensor de gas (27)(28)(29) y varistor a voltajes bajos (30); un estudio completo de este sistema fue realizado por Cassia-Santos (31). Además de ser un prometedor candidato para la detección de gases, el sistema SnO 2 /TiO 2 se considera como un potencial sensor de humedad (32,33); este sistema complejo se ve beneficiado por la combinación de las propiedades sensoras de sus componentes.…”

Section: Introductionunclassified

Uso de métodos químicos para obtener polvos cerámicos del sistema (Sn, Ti)O<sub>2</sub>

Ararat¹,

Varela²,

Páez³

2005

Bol. Soc. Esp. Ceram. Vidr.

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El sistema (Sn,Ti)O 2 , puro o dopado, tiene gran interés por las potencialidades tecnológicas que presenta como sensor de gas y varistor. A pesar del amplio estudio realizado de este sistema binario, respecto a las propiedades termodinámicas y cinéticas de la descomposición espinoidal que en él se presenta, sus propiedades y sus posibles aplicaciones no se han abordado con profundidad. Por otro lado, se ha realizado muy poco trabajo para optimizar métodos de síntesis que permitan obtener polvos cerámicos de (Sn,Ti)O 2 , puro o dopado, con características físicas y químicas pre-determinadas. En este trabajo se realizó la síntesis de polvos cerámicos de este sistema utilizando los métodos de coprecipitación y precursor polimérico (Pechini) y se discutieron los diferentes fenómenos fisicoquímicos que ocurren durante la síntesis. Los polvos obtenidos se caracterizaron con Difracción de Rayos X (DRX), análisis térmicos (ATD/TG) y Microscopia Electrónica de Barrido (MEB). La determinación de las diferentes etapas del proceso, como de los parámetros involucrados en el mismo, permitió el control de la síntesis y la obtención de partículas nanométricas del sistema (Sn,Ti)O 2 a temperaturas bajas: 450°C para coprecipitación y 600°C para el método Pechini. Además, se discutió el fenómeno de descomposición espinoidal que presentan las muestras tratadas a 900°C. Palabras Clave: Síntesis, (Sn,Ti)O 2 , Coprecipitación, Precursor Polimérico. Use of chemical methods to obtain (Sn, Ti)0 2 ceramic powdersThe (Sn,Ti)O 2 system has a great interest due to its technological applications such as gas sensor and varistor. Although the thermodynamic properties and the kinetics of spinoidal decomposition in this system have been extensively studied, the general properties and applications of SnO 2 -TiO 2 binary compositions have been not investigated yet in depth. On the other hand, little work has been done to optimize the synthesis methods to obtain (Sn,Ti)O 2 ceramic powders, with pre -determinate physical and chemical characteristics. In this work the ceramic powders has been obtained by coprecipitation and polymeric precursor (Pechini) methods. The different physical chemistry phenomena that occurred during the synthesis were discussed. The (Sn,Ti)O 2 ceramic powders were characterized with X-ray diffraction (XRD), thermal analysis (DTA/ TG) and scanning electron microscopy (SEM). The knowledge about of steps and variables of synthesis process acquired with development of this work, we permited to obtain (Sn, Ti)O 2 nanometers particles to low temperatures: to 450°C for coprecipitation method and to 600°C for Pechini method. The spinodal decomposition that ocurr to 900°C was discussed also.

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SnO2–TiO2 solid solutions for gas sensors

Cited by 157 publications

References 13 publications

Electronic and structural properties of SnxTi1−xO2 solid solutions: a periodic DFT study

Electronic and structural properties of SnxTi1−xO2 solid solutions: a periodic DFT study

Structural evolution of SnO2TiO2 nanocrystalline films for gas sensors

Uso de métodos químicos para obtener polvos cerámicos del sistema (Sn, Ti)O<sub>2</sub>

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