Optical chemical sensors using polythiophene derivatives as active layer for detection of volatile organic compounds

Gonçalves, Vagner; Balogh, Débora Terezia

doi:10.1016/j.snb.2011.12.084

Cited by 67 publications

(43 citation statements)

References 26 publications

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“…Lee et al [41] pointed out that there is a relation between reduction in absorption intensity and the swelling of the polymer film in presence of the gas analyte. Indeed, it is believed that the increase in the volume can promote the dilution of the chromophores (parts of a molecule responsible for its color) and consequently results in a decrease in the absorbance [42]. This is in accordance to our previous discussions suggesting Fig.…”

Section: Electronic Transport Propertiessupporting

confidence: 92%

Alcohol Sensibility of One-Dimensional Polyaniline and Polypyrrole Nanostructures

Joulazadeh

Navarchian

2015

IEEE Sensors J.

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This paper addresses the preparation of onedimensional nanostructured polyaniline (PANI) and polypyrrole (PPy). The Fourier transform infrared spectroscopy was used to characterize the chemical structure of the samples. The morphology of the samples was investigated by scanning electron microscopy and transmission electron microscopy. A nanofibrillar morphology was observed for the synthesized PANI and a nanotubular structure was obtained in the case of PPy. The alcohol sensing behaviors of PANI and PPy nanostructures were investigated for methanol, ethanol, propanol, and butanol, and the sensing mechanism of these systems has been discussed in detail. Both PANI and PPy systems were capable of detecting very low alcohols concentration (as low as 3 ppm) and demonstrated a linear behavior with a fast response/recovery performance especially in the case of ethanol vapor. The PPy-based sensor showed a better cyclability in response as compared with PANI when exposed to ethanol atmosphere. The surface characteristics of the PANI and PPy sensitive layers were investigated via atomic force microscopy. Ultraviolet-visible spectroscopy was used to study the effect of alcohol exposure on the electronic transport properties of nanostructured PANI and PPy layers.

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Section: Electronic Transport Propertiessupporting

confidence: 92%

Alcohol Sensibility of One-Dimensional Polyaniline and Polypyrrole Nanostructures

Joulazadeh

Navarchian

2015

IEEE Sensors J.

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“…Of these, Pani and PPy have been studied the most for many practical applications, such as sensors (Ansari et al, 2011;Patois et al, 2012), photocatalytic activity (Ansari et al, 2014a), environment remediation (Kumar et al, 2013) etc. Despite being the least ACCEPTED MANUSCRIPT ϴ studied, PTh has shown many promising applications comparable to both Pani and PPy, such as electrical/electrochemical applications, sensors and dye degradation (Gonçalves et al, 2012).…”

Section: Polythiophenementioning

confidence: 99%

Polythiophene nanocomposites for photodegradation applications: Past, present and future

Khan

Ansari

2015

Journal of Saudi Chemical Society

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Polythiophene (PTh) has been the subject of considerable interest because of its good environmental stability, unique redox electrical behavior, stability in doped and neutral states, ease of synthesis, and wide range of applications in many fields. Apart from its applications in the electrical or electronic field, PTh has shown promising applications in photocatalytic degradation. The fabrication of a catalyst, metal oxides with PTh, extends the absorption range of the modified composite system, thereby enhancing the photocatalytic activity under UV or visible light irradiation. Substituted PTh, such as alkyl substitution, modifies the electronic properties of the polymer, thereby enlarging the potential for industrial applications. PTh or substituted PTh when combined with metal, metal oxide or a combination of both, can exhibit tailorable photocatalytic properties. This review focuses on the chemistry of the band gap engineering of PTh or PTh based systems and the mechanism of photocatalytic degradation. The major developments in the field of UV and visible light-assisted photocatalysis are discussed in terms of the parameters that affect the photocatalytic efficiency. On the other hand, some ACCEPTED MANUSCRIPT ϯ challenges will still need to be investigated experimentally, which will be mentioned as the scope for future studies. For simplicity, the review has been classified under a major subheading depending on the type of composite system used for photocatalysis.

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“…An optical-chemical method for sensing the gases reacted with organic compounds by ultraviolet-visible spectral measurements has also been proposed in literature. 42 However, for AgAlS 2 , because its high sensitivity to moisture and speedilyphotodarkening effect on sample surface (see Fig. 1) detections of the light-intensity change by transmission or reflection measurement might be a dominant way for humidity sensing.…”

Section: Shows Temperature Dependences Of Transition Energies [E a (Tmentioning

confidence: 99%

Surface sensing behavior and band edge properties of AgAlS2: Experimental observations in optical, chemical, and thermoreflectance spectroscopy

Pan

2012

AIP Advances

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Optical examination of a chaocogenide compound AgAlS2 which can spontaneously transfer to a AgAlO2 oxide has been investigated by thermoreflectance (TR) spectroscopy herein. The single crystals of AgAlS2 were grown by chemical vapor transport (CVT) method using ICl3 as a transport agent sealed in evacuated quartz tubes. The as-grown AgAlS2 crystals essentially possess a transparent and white color in vacuum. The crystal surface of AgAlS2 becomes darkened and brownish when putting AgAlS2 into atmosphere for reacting with water vapor or hydrogen gas. Undergoing the chemical reaction process, oxygen deficient AgAlO2-2x with brownish and reddish-like color on surface of AgAlS2 forms. The transition energy of deficient AgAlO2-2x was evaluated by TR experiment. The value was determined to be ∼2.452 eV at 300 K. If the sample is kept dry and moved away from moisture, AgAlS2 crystal can stop forming more deficient AgAlO2-2x surface oxides. The experimental TR spectra for the surface-reacted sample show clearly two transition features at EW=2.452 eV for deficient AgAlO2-2x and EU=3.186 eV for AgAlS2, respectively. The EU transition belongs to direct band-edge exciton of AgAlS2. Alternatively, for surface-oxidation process of AgAlS2 lasting for a long time, a AgAlO2 crystal with yellowish color will eventually form. The TR measurements show mainly a ground-state band edge exciton of E OX 1 detected for AgAlO2. The energy was determined to be E OX 1 =2.792 eV at 300 K. The valence-band electronic structure of AgAlS2 has been detailed characterized using polarized-thermoreflectance (PTR) measurements in the temperature range between 30 and 340 K. Physical chemistry behaviors of AgAlS2 and AgAlO2 have been comprehensively studied via detailed analyses of PTR and TR spectra. Based on the experimental analyses, optical and chemical behaviors of the AgAlS2 crystals under atmosphere are realized. A possible optical-detecting scheme for using AgAlS2 as a humidity sensor has also been proposed

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Optical chemical sensors using polythiophene derivatives as active layer for detection of volatile organic compounds

Cited by 67 publications

References 26 publications

Alcohol Sensibility of One-Dimensional Polyaniline and Polypyrrole Nanostructures

Alcohol Sensibility of One-Dimensional Polyaniline and Polypyrrole Nanostructures

Polythiophene nanocomposites for photodegradation applications: Past, present and future

Surface sensing behavior and band edge properties of AgAlS2: Experimental observations in optical, chemical, and thermoreflectance spectroscopy

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