A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Selected papers from the latest issue:
Enhanced response characteristics of SnO2thin film based sensors loaded with Pd clusters for methane detection
29 February 2012, 02:16:20
Publication year: 2012
Source: Sensors and Actuators B: Chemical, Available online 28 February 2012
Divya Haridas, Vinay Gupta
This paper reports the response characteristics of rf-sputtered SnO2thin films (90 nm thin) loaded with nanoscale catalytic clusters for detection of methane. Ultrathin (8 nm) metal and metal-oxide catalysts (Pt, Ag, Ni, Pd, Au, NiO, Au2O3) clusters are loaded over the surface of SnO2thin film. The SnO2-Pd cluster structure is found to exhibit an enhanced response (97.2%) for 200 ppm of methane at a relatively low operating temperature (220 °C). The enhanced response is shown to be primarily due to the dominant roles played by both Fermi level energy control mechanism and spillover mechanism. Thickness of the Pd catalyst clusters in the nano-scale range (2 to 20 nm), influences significantly the sensor characteristics. Optimized performance is observed with 10 nm thick Pd catalyst clusters showing a high response (∼99.2%) at a relatively low operating temperature of 160 °C. Thickness of the Pd clusters is shown to influence the amount of adsorbed oxygen present on the uncovered SnO2film surface and also activates the spillover mechanism. The results suggest the possibility of utilizing the sensor structure having novel dispersal of Pd catalyst clusters (10 nm thickness) on the surface of SnO2thin film for efficient detection of methane gas.
Source: Sensors and Actuators B: Chemical, Available online 28 February 2012
Divya Haridas, Vinay Gupta
This paper reports the response characteristics of rf-sputtered SnO2thin films (90 nm thin) loaded with nanoscale catalytic clusters for detection of methane. Ultrathin (8 nm) metal and metal-oxide catalysts (Pt, Ag, Ni, Pd, Au, NiO, Au2O3) clusters are loaded over the surface of SnO2thin film. The SnO2-Pd cluster structure is found to exhibit an enhanced response (97.2%) for 200 ppm of methane at a relatively low operating temperature (220 °C). The enhanced response is shown to be primarily due to the dominant roles played by both Fermi level energy control mechanism and spillover mechanism. Thickness of the Pd catalyst clusters in the nano-scale range (2 to 20 nm), influences significantly the sensor characteristics. Optimized performance is observed with 10 nm thick Pd catalyst clusters showing a high response (∼99.2%) at a relatively low operating temperature of 160 °C. Thickness of the Pd clusters is shown to influence the amount of adsorbed oxygen present on the uncovered SnO2film surface and also activates the spillover mechanism. The results suggest the possibility of utilizing the sensor structure having novel dispersal of Pd catalyst clusters (10 nm thickness) on the surface of SnO2thin film for efficient detection of methane gas.
Polymer-assisted synthesis of metallopolymer nanocomposites and their applications in liquefied petroleum gas sensing at room temperature
29 February 2012, 02:16:20
Publication year: 2012
Source: Sensors and Actuators B: Chemical, Available online 28 February 2012
Satyendra Singh, B.C. Yadav, Poonam Tandon, Mridula Singh, Anuj Shukla, ...
In this paper, the synthesis of the acrylamide complex of Co (II) nitrate followed by polymerization and formation of a polymer composite with inclusions of Co nanoparticles stabilized by the polymer matrix has been reported. Cobalt polyacrylamide (Co/PAAM) was prepared by the procedure including formation of cobalt acrylamide complex, followed by frontal polymerization and pyrolysis of the polymer. Structural investigations of the materials were carried out by X-ray diffractometer. Surface morphologies were analysed using scanning electron microscope and nano-structural properties were studied by using high resolution transmission electron microscope and atomic force microscope. Phase transformation temperature was evaluated using a differential scanning calorimeter. The crystallite size of the Co/PAAM was found ∼ 6 nm and confirmed by TEM analysis. Thick films of the metallopolymers were made by screen printing technique and these were investigated with exposition of LPG for measurements of LPG sensing characteristics. Larger variations in resistance were found for Co/PAAM in comparison to Co(NO3)2.(AAM)4.2H2O. The maximum values of the sensitivities were 2.9 and 23.6 MΩ/sec for Co(NO3)2.(AAM)4.2H2O and Co/polyacrylamide respectively. The reproducibility of the sensor made of Co/PAAM film was found to be 96% after one month of observations, which shows the stability and reliability of the fabricated sensor
Source: Sensors and Actuators B: Chemical, Available online 28 February 2012
Satyendra Singh, B.C. Yadav, Poonam Tandon, Mridula Singh, Anuj Shukla, ...
In this paper, the synthesis of the acrylamide complex of Co (II) nitrate followed by polymerization and formation of a polymer composite with inclusions of Co nanoparticles stabilized by the polymer matrix has been reported. Cobalt polyacrylamide (Co/PAAM) was prepared by the procedure including formation of cobalt acrylamide complex, followed by frontal polymerization and pyrolysis of the polymer. Structural investigations of the materials were carried out by X-ray diffractometer. Surface morphologies were analysed using scanning electron microscope and nano-structural properties were studied by using high resolution transmission electron microscope and atomic force microscope. Phase transformation temperature was evaluated using a differential scanning calorimeter. The crystallite size of the Co/PAAM was found ∼ 6 nm and confirmed by TEM analysis. Thick films of the metallopolymers were made by screen printing technique and these were investigated with exposition of LPG for measurements of LPG sensing characteristics. Larger variations in resistance were found for Co/PAAM in comparison to Co(NO3)2.(AAM)4.2H2O. The maximum values of the sensitivities were 2.9 and 23.6 MΩ/sec for Co(NO3)2.(AAM)4.2H2O and Co/polyacrylamide respectively. The reproducibility of the sensor made of Co/PAAM film was found to be 96% after one month of observations, which shows the stability and reliability of the fabricated sensor
Scaling laws and performance improvements of integrated biosensor microarrays with multi-pixel per spot
29 February 2012, 02:16:20
Publication year: 2012
Source: Sensors and Actuators B: Chemical, Available online 28 February 2012
N. Couniot, A. Afzalian, D. Flandre
Multiplexed, real-time and low cost detection of bioanalytes can be achieved by building integrated biosensor microarrays. The lack of design guidelines for this kind of biochip leads to inferior results compared to individual biosensors. In this paper, we thoroughly study the impact of considering several pixels per spot on the performances of integrated biosensor microarrays. By taking into account the biological shot noise and electrical characteristics of the transducer, we theoretically calculate how dividing each spot into several pixels improves the limit of detection and the resolution of the overall biosensor microarray without degrading the signal-to-noise ratio. More particularly, we show that the improvement of the limit of detection depends on the individual biosensor performance while the resolution is enhanced proportionally to the square root of number of pixels per spot. Performance trade-offs, CMOS compatibility and numerical results for optical, field-effect and capacitive biosensor microarrays having multiple pixels per spot are finally established.
Source: Sensors and Actuators B: Chemical, Available online 28 February 2012
N. Couniot, A. Afzalian, D. Flandre
Multiplexed, real-time and low cost detection of bioanalytes can be achieved by building integrated biosensor microarrays. The lack of design guidelines for this kind of biochip leads to inferior results compared to individual biosensors. In this paper, we thoroughly study the impact of considering several pixels per spot on the performances of integrated biosensor microarrays. By taking into account the biological shot noise and electrical characteristics of the transducer, we theoretically calculate how dividing each spot into several pixels improves the limit of detection and the resolution of the overall biosensor microarray without degrading the signal-to-noise ratio. More particularly, we show that the improvement of the limit of detection depends on the individual biosensor performance while the resolution is enhanced proportionally to the square root of number of pixels per spot. Performance trade-offs, CMOS compatibility and numerical results for optical, field-effect and capacitive biosensor microarrays having multiple pixels per spot are finally established.
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