Study of the correlation between sensing performance and surface morphology of inkjet-printed aqueous graphene-based chemiresistors for NO₂ detection

• F. Villani,
• C. Schiattarella,
• T. Polichetti,
• R. Di Capua,
• F. Loffredo,
• B. Alfano,
• M. L. Miglietta,
• E. Massera,
• L. Verdoliva and
• G. Di Francia

Beilstein J. Nanotechnol. 2017, 8, 1023–1031, doi:10.3762/bjnano.8.103

• comparing the response of different chemiresistors fabricated by dispensing the same suspension also onto Al2O3 and Si/SiO2 substrates and carrying out a supportive atomic force microscopy analysis. The results prove the possibility to produce sensor devices by means of a wholly environmentally friendly

• , the I–V curve of the device D-P17 is reported in Figure 3. The sensing properties of the chemiresistors have been tested by exposing the devices to NO2, the analyte towards which LPE graphene is more specific [16]. In Figure 4a, the dynamic responses toward 1 ppm of NO2 for paper-based devices are

• substrate surface, so envisaging an indirect effect of the substrate onto the sensing layer morphology. Typical for graphene-based chemiresistors operating at room temperature, the sensing curves show slow recovery behavior. This implies several hours for reaching the initial conductance values or the

CVD transfer-free graphene for sensing applications

• Chiara Schiattarella,
• Sten Vollebregt,
• Tiziana Polichetti,
• Brigida Alfano,
• Ettore Massera,
• Maria Lucia Miglietta,
• Girolamo Di Francia and
• Pasqualina Maria Sarro

Beilstein J. Nanotechnol. 2017, 8, 1015–1022, doi:10.3762/bjnano.8.102

• straightforward integration in electronic devices. Keywords: ammonia; chemiresistors; CMOS-compatible process; graphene; nitrogen dioxide; transfer-free growth; Introduction Due to its extraordinary electronic, chemical, mechanical, thermal and optical properties, graphene has been defined as the “wonder

• extent. Figure 3 displays the dynamic response of the conductance of the devices towards 1 ppm of NO2. As can be observed, the base conductance values are comparable (GA ≈ GB ≈ 22 µS). During exposure, both chemiresistors exhibit an identical percentage variation of the conductance without reaching a

• have been exposed to NH3. Even in this case both chemiresistors exhibit a comparable percentage variation of the conductance, as well as similar kinetics (Figure 4). Because ammonia is an electron-donor analyte, the conductance show a decrease, further confirming the p-type nature of the synthesized

BTEX detection with composites of ethylenevinyl acetate and nanostructured carbon

• Santa Stepina,
• Astrida Berzina,
• Gita Sakale and
• Maris Knite

Beilstein J. Nanotechnol. 2017, 8, 982–988, doi:10.3762/bjnano.8.100

• use of nanocarbons increases the detection range as well as the electrical conductivity of the chemiresistors and decreases the temperature dependence. Hybrid composites were made of poly(dimethyl siloxane) (PDMS) with nanocarbon black (NCB) and carbon nanotubes (CNT) as fillers and these composites

Gas sensing properties of MWCNT layers electrochemically decorated with Au and Pd nanoparticles

• Elena Dilonardo,
• Michele Penza,
• Marco Alvisi,
• Riccardo Rossi,
• Gennaro Cassano,
• Cinzia Di Franco,
• Francesco Palmisano,
• Luisa Torsi and
• Nicola Cioffi

Beilstein J. Nanotechnol. 2017, 8, 592–603, doi:10.3762/bjnano.8.64

• (MWCNT)-based chemiresistors were electrochemically decorated with Au and Pd nanoparticles (NPs), resulting in an improvement in the detection of gaseous pollutants as compared to sensors based on pristine MWCNTs. Electrophoresis was used to decorate MWCNTs with preformed Au or Pd NPs, thus preserving

• large surface area and hollow structure, that make them potentially applicable as a sensing layer in gas sensors [7][8]. Semiconducting MWCNTs are frequently used in chemiresistors, since they are extremely sensitive to charge transfer and chemical doping effects in the presence of oxidizing or reducing

• total surface amount of deposited Au NPs, and therefore, on the surface chemical composition. In this contribution, we compare the sensing performance of Pd-modified MWCNT-based chemiresistors to that of Au-modified MWCNT-based chemiresistors (already investigated in previous study [19]) towards the

Sensitive detection of hydrocarbon gases using electrochemically Pd-modified ZnO chemiresistors

• Elena Dilonardo,
• Michele Penza,
• Marco Alvisi,
• Gennaro Cassano,
• Cinzia Di Franco,
• Francesco Palmisano,
• Luisa Torsi and
• Nicola Cioffi

Beilstein J. Nanotechnol. 2017, 8, 82–90, doi:10.3762/bjnano.8.9

• interfering gaseous pollutants (e.g., NO2) revealed that the presence of Pd NPs on the surface of ZnO improves the selectivity in the detection of specific gaseous molecules. Specifically Pd@ZnO chemiresistors showed a high selectivity towards HCs compared to the pristine ZnO-based gas sensors. On the

• contrary, high selectivity towards NO2 gas detection was obtained by using pristine ZnO chemiresistors. Experimental Sol–gel synthesis of ZnO ZnO nanostructures were prepared via a sol–gel process following the procedure reported in [45]. The subsequent washing of the obtained gel led to the complete

• . The presence of Pd NPs on ZnO NRs strongly affects gas adsorption and reactivity and, hence, the gas sensing as discussed in the following section. Gas-sensing performance Figure 4A shows the time responses of the electrical resistance of chemiresistors based on pristine and Pd-modified ZnO NRs to

Evaluation of gas-sensing properties of ZnO nanostructures electrochemically doped with Au nanophases

• Elena Dilonardo,
• Michele Penza,
• Marco Alvisi,
• Cinzia Di Franco,
• Francesco Palmisano,
• Luisa Torsi and
• Nicola Cioffi

Beilstein J. Nanotechnol. 2016, 7, 22–31, doi:10.3762/bjnano.7.3

• and C) 550 °C, and of Au@ZnO hybrid systems annealed at D) 300 °C and E) 550 °C. A) Time response of chemiresistors based on pristine and Au-doped ZnO annealed at 300 °C, exposured to different NO2 concentrations [0.5–10 ppm] at operating temperature of 300 °C; B) enlarged parts of the dynamic

• response curve shown in a at a NO2 concentration of 10 ppm drawn to reveal the moments of gas input and gas stop. C) time response of chemiresistors based on pristine and Au-doped ZnO annealed at 550 °C, exposed to different NO2 concentrations [0.2–10 ppm] at an operating temperature of 300 °C; D) enlarged

Chemiresistive/SERS dual sensor based on densely packed gold nanoparticles

• Sanda Boca,
• Cosmin Leordean,
• Simion Astilean and
• Cosmin Farcau

Beilstein J. Nanotechnol. 2015, 6, 2498–2503, doi:10.3762/bjnano.6.259

• , 400084 Cluj-Napoca, Romania 10.3762/bjnano.6.259 Abstract Chemiresistors are a class of sensitive electrical devices capable of detecting (bio)chemicals by simply monitoring electrical resistance. Sensing based on surface enhanced Raman scattering (SERS) represents a radically different approach, in

• share a common principle: nanometric interparticle gaps are needed, for electron tunneling in chemiresistors, and for enhancing electromagnetic fields by plasmon coupling in SERS-based sensors. By exploiting such nano-gaps in self-assembled films of gold nanoparticles, we demonstrate the proof of

• sensors are chemiresistors, which are sensitive electrical devices capable of detecting (bio)chemicals by simply monitoring electrical resistance. They require simple DC circuitry, and are therefore ideal for developing wearable/portable devices for protection from chemical exposure, or for environmental