2,602 Works

P1MM.7 - Discrimination Among Different Lemon Juice Samples Using Chronoamperometry in a Microfluidic Channel

A. Souri, H. Sardari & F. Hossein-Babaei
Food quality control has always been an issue for both the food producer and consumer. The dominant trend in analyses of fluids is miniaturization based on microfluidics concepts. Here, we demonstrate discriminating between different lemon juice samples by performing a chronoamperometry in a microfluidic channel. A droplet of lemon juice is injected into a microfluidic channel and a voltage waveform is applied on the channel from a preprogramed power supply. The temporal variations of the...

P1MM.6 - Fabrication Concept for Biomimetic Microfluidic Systems

J. Zehetner, S. Kasemann, E. Kostal, G. Vanko & O. Babchenko
This work reports the results obtained by using a technological process combining reactive ion etching (RIE) and laser ablation in the femtosecond regime. We produce membranes, micro- and nanostructured surfaces as well as 3D structures for application oriented research. Our focus is on microfluidic devices, MEMS and pressure sensors. Primarily we use AlGaN/GaN heterostructure layers grown on 4H-SiC or Si substrates, glass and ceramics. We demonstrate a novel method of direct mask writing into a...

P1MM.5 - Optimization of Silicon and Quartz MEMS Microheater for Chemoresistive Gas Sensors

A. Gaiardo, P. Bellutti, M. Crivellari, A. Bagolini, V. Guidi, C. Malagu, B. Fabbri & M. Valt
In the last years, the research in the gas sensor field experienced a significant boost. Gas sensors represent the crucial elements in gas monitoring systems and olfactory systems for several applications: environmental monitoring, safety and security, quality control of food production, medical diagnosis and so on. From the point of view of the gas sensing design, the substrate plays a fundamental role, because acts as a heater, mechanical support and transducer of the sensor response....

P1MM.4 - MEMS-Based Conductometric Sensors for Organic Airborne Particles

R. Horiuchi, N. Jimbo, T. Yamaguchi & K. Hara
We have developed MEMS-based conductometric sensors for detection of smaller organic airborne particles such as PM2.5 and house dust which may cause a variety of diseases. A sensor is composed of two parts: a sensing element and a micro heater. Both parts were fabricated by using thin film technology, IC fabrication process and micromachining technique. The resistance of the sensor steeply decreased and then recovered to the initial value. A small increase appeared before or...

P1MM.3 - Solution-Gated Graphene FET DNA sensor for using unique coplanar gate structure integrated in the microfluidic chip

H. E. Kim, J. H. Lee, A. Schuck & Y.-S. Kim
In this work, we have developed a solution-gated graphene field effect transistors (SGGFETs) for sensing single-stranded DNA by unique coplanar gate structure design. Coplanar electrodes and graphene active layer are all exposed outside the plane to integrate with microfluidic chip. Integrating the microfluidic into the FETs, a certain amount and path of the DNA solution can be controlled optionally by microfluidic channel. [1] The probe DNA (10 μM) was injected through the microfluidic channel and...

P1MM.2 - Capillary introduction of polydimethylsiloxane precursor to microfabricated structure

A. Hibara, A. Akiyama, K. Furukawa & K. Ishikawa
Capillary introduction colored polydimethylsiloxane (PDMS) precursor liquid to microfabricated straight channels was analyzed for opto-fluidic applications. The PDMS liquid was colored by Japanese black ink. The black PDMS is potentially used for light-shielding material after introduction. PDMS-glass microfluidic chips were used. Microchannels having in/out ports at both ends (open-end channel) and those having only one in/out port (dead-end channel) were prepared. The open-end channels were used for analyzing viscosity during the capillary introduction. Viscosity decrease...

P1MM.1 - Development of a Polymer Inclusion Membrane Incorporated in a Microfluidic Paper-Based Sensor for the Determination of Cu(II)

L. N. Sibal, L. DlC. Coo, R. A. B. Camitan, D. A. O. Yabut & B. A. Rivera
A polymer inclusion membrane (PIM) incorporated in a microfluidic paper-based sensor (μPBS) was prepared for the optical determination of copper in water samples. The PIM composition needed to achieve high selectivity and sensitivity for the analytical determination of Cu(II) ions was optimized. It was composed of 8 wt% dioctyl phthalate, 51.5 wt% poly(vinyl chloride), 40 wt% di-(2-ethylhexyl) phosphoric acid and 0.5 wt% 2-(2-thiazolylazo)-p-cresol (TAC). TAC reacts with Cu(II) producing a green-colored complex. The μPBS was...

P1GS.23 - Hydrogen Sulfide Gas Sensor Based on Conducting Polyimide/Gold Nanoparticles

K. S. Santiago, L. M. G. Padua & J.-M. Yeh
This work presents the development of H2S gas sensor based on conducting polyimide/gold nanoparticles (CPI/AuNPs). The sensing membrane was prepared via a facile two-step process of polymerization and imidization to obtain CPI, followed by incorporation of AuNPs into the polymer matrix through reduction of HAuCl4. The success of synthesis was confirmed via Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy-energy dispersive X-rays (SEM-EDX). The FTIR spectra confirmed the presence of functional groups that constitute...

P1GS.22 - Tin Oxide Gas Sensor on Tin Oxide Microheater for Methane Sensing

M. Moalaghi, M. Gharesi & A. Ranjkesh
Despite the ever increasing demand for methane detection in residential and industrial locations, the common tin oxide-based methane sensors fail to satisfy the quality requirements for long-term operation in harsh environs. Particularly, the RuO2 microheaters utilized in these sensors deteriorate in reducing atmospheres and cannot provide the high temperatures required for methane detection in a long-time period. Here, we disclose a tin oxide gas sensor complete on a tin oxide microheater which can stably operate...

P1GS.21 - Dosimeter for Low-Level NOx Detection – Influence of the Deposition Method of the NOx Storage Film

D. Schönauer-Kamin, M. Schubert, Y. Jännsch, H. Kurz, I. Marr & R. Moos
The detection of low-level NOx concentrations and the dose of NOx for air-quality monitoring (AQM) is still a huge task and a widely discussed topic. Dosimeter-type NOx sensors detect directly the NOx dose and are advantageous considering mean value detection, linearity of sensor responses, and drift phenomena. The electrical properties of a NOx storage film, here potassium permanganate impregnated on alumina powder, depend linearly on the amount of sorbed NOx. The electrical resistance correlates very...

P1NM.20 - Isoprene detection with Ti-doped ZnO nanoparticles

D. Klein Cerrejon, A. T. Güntner, N. J. Pineau, D. Chie, F. Krumeich & S. E. Pratsinis
Exhaled isoprene could enable non-invasive real-time monitoring of cholesterol-lowering therapies. Here, we report an isoprene-selective sensor at high relative humidity (RH). It is made of nanostructured, chemo-resistive Ti-doped ZnO nanoparticles produced by flame spray pyrolysis (FSP) and directly deposited onto sensor substrates forming highly porous films. The constituent particles consist of stable Ti-doped ZnO solid solutions for Ti levels up to 10 mol%. Ti doping strongly enhance the isoprene sensitivity (>15 times higher than pure...

P1GS.20 - An ultrasensitive and humidity resistant NO2 gas sensor based on BP-BV composite film at room temperature

R. Hao, Z. Yong & G. Yongcai
In this paper, black phosphorus (BP) based thin film serving as a sensing layer was prepared for trace-level nitrogen dioxide (NO2) gas detection within different relative humidities (R.H.). Meanwhile, multiple characterization techniques containing TEM, XRD, XPS and Raman were employed to auxiliarily unveil the gas-sensing mechanism. Benzyl viologen (BV), owning one of the highest reduction potentials of all electron donor organic compounds, was incorporated into BP flakes, and thus resulted in a sensing response of...

P1NM.19 - Silicon Nanowire pH Sensors Fabricated Using Conventional CMOS Technologies

Z. Wang, Z. Zhao, K. Zhou & L. Pan
This paper reports a fabrication method and an integration scheme for silicon nanowire (SNW) pH sensors. By using sidewall techniques, SNW with feature size down to nanometer regime can be obtained using conventional CMOS technology. The SNWs are operated in a FET configuration as a pH sensor, and sensitivity as high as 54.5 mV/pH for pH values from 1 to 12 is achieved.

P1NM.18 - Sensing Properties of Nanocrystalline Silicon Carbide in Wet Condition

A. Gaiardo, B. Fabbri, M. Valt, C. Malagù, V. Guidi, G. Pepponi, P. Bellutti & A. Giberti
Silicon carbide is a well-known material with high thermal and chemical stability. In this work, we present an investigation on the chemoresistive properties of nanostructured Silicon Carbide (SiC). A commercially available nanopowder of silicon carbide was first purified and then its morphology, structure and thermal stability was characterized. Afterwards, the powder was mixed with suitable organic vehicles and screen-printed onto alumina substrates. SiC thick films were tested as chemoresistive gas sensors in thermo-activation mode. In...

P1GS.19 - Cobalt spinel via solution combustion synthesis as an ammonia sensing material

D. Ziegler, A. Marchisio, G. Ercolino, S. Specchia & J. M. Tulliani
Nano-crystalline cobalt oxide (Co3O4) was prepared by solution combustion synthesis (SCS) and used as ammonia sensing material. The obtained powder was characterized by laser granulometry, thermal analysis, X-ray diffraction, X-ray Photoelectron Spectroscopy, nitrogen adsorption (B.E.T -Brunnauer, Emmet, Teller- technique), Raman spectroscopy, field emission scanning electron microscopy and transmission electron microscopy. Sensors were screen-printed onto α-alumina substrates with platinum interdigitated electrodes and fired at 700°C for 1 h in air, after drying overnight. The sensor’s response...

P1NM.17 - Functional Graphene oxide and role of hydroxyl groups on humidity sensing

A. A. Haidry, Q. Fatima, L. Sun, Z. Li, L. Xie & Z. Yao
In this work we prepared Graphene oxide with modified Hummers method. We study the effect of hydroxyl groups on the humidity sensing properties at room temperature with low voltage of 0.1 V and fast response time. The functionality of the GO was intensively studied by using Fourier-transform infrared spectroscopy. We performed intensive gas sensing and electrical measurements coupled with mandatory XRD, SEM, FTIR and Raman experiment which show promising results. The analysis shows that the...

P1GS.18 - BaTi-Oxides as High-Temperature Nitrogen Oxide Sensors

B. Saruhan-Brings & R. Lontio Fomekong
NOx-detection at high temperatures is complicated due to the thermal conversion of nitrogen oxides. Moreover, multiple gas combinations in the environment where nitrogen oxides are present require high selectivity. Nobel metal incorporated BaTi-Oxides have shown good high temperature sensing ability, although the factors affecting selectivity as well as the sensing mechanism are not fully established. This work yields a systematic study using different phase and morphologies of the BaTioxide based sensing material.

P1NM.16 - A Highly Sensitive Determination of Vitamin D in Supplements Using Graphene-Nafion Nanocomposite

W. Siangproh, A. Yakoh & O. Chailapakul
In this work, we describe an antifouling strategy for highly sensitive determination of fat-soluble vitamin D based on graphene/nafion nanocomposite. Graphene based screen-printable ink was used to fabricate graphene/nafion nanocomposite with good reproducibility. Besides the sensitivity improvement, a graphene/nafion nanocomposite exhibited a lower background current in comparison with carbon and graphene screen-printed electrode (SPE), which resulted in a larger signal-tobackground (S/B) ratio. In addition, under the synergistic effect of graphene and nafion, a sensitive, reusable,...

P1GS.17 - WO3 Nanowires Decorated with Nickel Oxide Nanoparticles for H2S Detection

E. Llobet, E. Navarrete, C. Bittencourt & P. Umek
Single-step or two-step aerosol assisted chemical vapor deposition methods have been used to grow single crystalline tungsten oxide nanowires loaded with different concentrations of nickel oxide nanoparticles. Working temperatures and nickel loadings were studied and optimized to achieve the optimal working conditions for detecting hydrogen sulfide. Morphology, crystalline structure, composition, sensing properties and mechanisms will be presented and discussed in detail. The twostep method allows for controlling Ni loading in a wide range while keeping...

P1GS.16 - SnO2/TiO2 thin film n-n heterostructures for H2 and NO2 gas sensing

K. Zakrzewska, P. Nowak, W. Maziarz, A. Rydosz & K. Kowalski
Pure SnO2 and SnO2/TiO2 heterostructure based gas sensors for reducing H2 and oxidizing NO2 in the temperature range of 80 400 °C were investigated. SnO2 thin films were prepared by RF magneton sputtering, whereas TiO2 layers were deposited using a relatively less exploited Langmuir-Blodgett (LB) technique. TiO2 thin films were characterized with different spectroscopy and imaging methods (XPS, XRD, EDS, SEM, optical profilometry) which confirmed the presence of TiO2 on the SnO2 surfaces. The resistance...

P1GS.15 - Sensitive and Selective H2S Gas Detection at Low Temperature Employing In2O3 Quantum Dots

H. Liu, S. Yang, Z. Song, N. Gao, Z. Hu, Q. Liu, J. Liu & B. Zhang
Indium oxide (In2O3) has been employed for gas sensors as an important candidate. Here we demonstrated the sensitive gas sensors based on In2O3 quantum dots synthesized via solvetheramal methodology. A room-temperature films deposition was utilized for sensor fabrication, followed by the Cu salt surface ligand exchange with a moderate annealing treatment. The In2O3 CQD-based gas sensors exhibited an excellent H2S-sensing performance with the response up to 90 upon 5 ppm H2S with a fast response...

P1NM.15 - Efficient Structural, Compositional and Morphological Modifications of TiO2-based Hierarchical Multicomponent Materials for Chemical Sensing

E. Comini, V. Galstyan, G. Sberveglieri, A. Ponzoni, I. Kholmanov, M. M. Natile & I. A. Glisenti
We have synthesized pure, mixed and multicomponent structures by coupling different cost-effective techniques. Prepared TiO2-based hierarchically assembled nanostructures have been thoroughly characterized by scanning electron microscope, X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. The sensing properties of materials have been studied towards explosive and toxic gaseous compounds. Investigations have shown the material crystalline structure, the variation of mixture concentration in the material and the modification of carbon-based layers have crucial effect on the response...

P1NM.14 - Percolating metallic structures templated on laser - deposited carbon nanofoams derived from graphene oxide: Applications in humidity sensing

S. Nufer, A. B. Dalton, J. P. Salvage, A. Shmeliov & A. Brunton
Carbon nanofoam (CNF) is a low-density, high-surface-area material formed by aggregation of amorphous carbon nanoparticles into porous nanostructures. We report the use of a pulsed infrared laser to prepare CNF from a graphene oxide (GO) target material. Electron microscopy shows that the films consist of dendritic strings which form web-like three-dimensional structures. The conductivity of these structures can be modified by using the CNF as a nanostructured scaffold for gold nanoparticles deposited by sputter coating,...

P1GS.14 - Gas Sensitivity Study of Films Based on Polymeric Phthalocyanines

S. Krutovertsev, A. Tarasova, O. Ivanova, L. Krutovertseva, A. Sherle & E. Oleinik
Organic semiconductive materials are known to considerably modify their electrophysical properties on adsorption of the active gases at low temperatures. The conductivity, resistance-temperature relationship, sensor properties relative to nitric oxide, oxygen and hydrogen sulfide of films based on oligo- and polyphthalocyanines containing Co, Cu, Fe and Mn were investigated in the present work. Polymeric films were deposited on the test structures with a pair of interdigital metal electrodes formed at their surface. The investigations were...

P1NM.13 - Impedance of Metal Organic Frameworks: On the Way to in-situ Monitoring of Proton Conducting Membranes

C. Weinberger, D. Klawinski, A. Javed, T. Homburg, N. Stock, M. Tiemann & T. Wagner
The presented project aims at the development of an in-situ characterization method for the development of new proton conducting Metal-Organic Frameworks (MOFs). A novel combination of water sorption technique with impedance spectroscopy allows identification of proton conduction mechanisms in complex nanomaterials. On standard proton conducting materials (e.g. Nafion) the relative humidity determines the dominating conduction type (proton hopping, Grotthuss or vehicle mechanism). Discrimination is possible by temperature resolved studies, which can be utilized for optimization...

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