Toward Planar Atomic-Gold Decorated Polyaniline Gas Sensors for Enhanced Electrochemical Sensing

Chakraborty, Parthojit; Faricha, Anifatul; Okamoto, Keisuke; Kawakami, Hiroki; Chang, Tso-Fu Mark; Sone, Masato; Nakamoto, Takamichi

doi:10.1109/jsen.2023.3242318

Cited by 8 publications

(11 citation statements)

References 28 publications

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“…PANI and PANI doped with ZnO have affinity towards various volatile substances, such as methanol, isopropanol, and benzyl alcohol 36 – 38 . Isopropanol was chosen as the test vapor due to its widespread use in pharmaceuticals, cosmetics, and cleaning products, making it readily available and good representative of volatile organic gases.…”

Section: Methodsmentioning

confidence: 99%

Unraveling the nature of sensing in electrostatic MEMS gas sensors

Shama,

Rahmanian,

Mouharrar

et al. 2024

Microsyst Nanoeng

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This paper investigates the fundamental sensing mechanism of electrostatic MEMS gas sensors. It compares among the responsivities of a set of MEMS isopropanol sensors before and after functionalization, and in the presence and absence of electrostatic fields when operated in static and dynamic detection modes. In the static mode, we found that the sensors do not exhibit a measurable change in displacement due to added mass. On the other hand, bare sensors showed a clear change in displacement in response to isopropanol vapor. In the dynamic mode, functionalized sensors showed a measurable frequency shift due to the added mass of isopropanol vapor. In the presence of strong electrostatic fields, the measured frequency shift was found to be threefold larger than that in their absence in response to the same concentration of isopropanol vapor. The enhanced responsivity of dynamic detection allows the sensors to measure the vapor mass captured by the functional material, which is not the case for static detection. The detection of isopropanol by bare sensors in static mode shows that change in the medium permittivity is the primary sensing mechanism. The enhanced responsivity of dynamic mode sensors when operated in strong electrostatic fields shows that their sensing mechanism is a combination of a weaker added mass effect and a stronger permittivity effect. These findings show that electrostatic MEMS gas sensors are independent of the direction of the gravitational field and are, thus, robust to changes in alignment. It is erroneous to refer to them as ‘gravimetric’ sensors.

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Section: Methodsmentioning

confidence: 99%

Unraveling the nature of sensing in electrostatic MEMS gas sensors

Shama,

Rahmanian,

Mouharrar

et al. 2024

Microsyst Nanoeng

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Section: Atomic Gold Depositionmentioning

confidence: 99%

“…Afterward, the modified Pt/PANI electrode was installed in the chamber where its two WEs and CE were connected to the line of WE and CE at potentiostat, respectively (the potentiostat was based on IC TL074, Texas Instruments, Dallas, TX, USA); since the RE from IDA made of Pt, hence, external Ag/AgCl was used as RE to maintain the stable EC reaction during the gold deposition process which connected to the RE line at potentiostat. Furthermore, the timing diagram of the deposition process to fabricate the Au 2 clusters is shown in Figure 2b [32][33][34][35], and modified Pt/PANI/Au 2 using IDA electrode is described in Figure 2c. Since the current commercial SEM technology is not able to be used to confirm the presence of atomic gold in PANI due to the resolution limits, the alternative way to confirm the Au 2 clusters, which have also been massively reported and applied, has been using the information of oxidation from propanol isomers in the alkaline medium [15,19,26,[32][33][34].…”

Section: Atomic Gold Depositionmentioning

confidence: 99%

“…In our previous research, in a bulky EC system, it was successfully demonstrated and verified that modifying platinum (Pt) WE with PANI and atomic gold clusters (Au n where n = 1 to 4) showed the electrocatalytic activity and exhibited an odd-even pattern for isomer compounds, particularly for the Au 2 clusters [32][33][34]. Afterward, a tiny planar IDA electrode modified with PANI decorated Au 2 clusters was successfully conducted and first reported by our research group; however, it used only one RTIL (1-ethyl-3-methylimidazolium trifluoromethanesulfonate) and one fixed EC potential (i.e., +1 V) [35,36]. In this study, we developed the miniaturized EC sensor array using the Au 2 clusters decorated Pt/PANI in three RTILs with different physical-chemical properties.…”

Section: Introductionmentioning

confidence: 99%

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Array of Miniaturized Amperometric Gas Sensors Using Atomic Gold Decorated Pt/PANI Electrodes in Room Temperature Ionic Liquid Films

Faricha

Yoshida

Chakraborty

et al. 2023

Sensors

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Miniaturized sensors possess many advantages, such as rapid response, easy chip integration, a possible lower concentration of target compound detection, etc. However, a major issue reported is a low signal response. In this study, a catalyst, the atomic gold clusters of Aun where n = 2, was decorated at a platinum/polyaniline (Pt/PANI) working electrode to enhance the sensitivity of butanol isomers gas measurement. Isomer quantification is challenging because this compound has the same chemical formula and molar mass. Furthermore, to create a tiny sensor, a microliter of room-temperature ionic liquid was used as an electrolyte. The combination of the Au2 clusters decorated Pt/PANI and room temperature ionic liquid with several fixed electrochemical potentials was explored to obtain a high solubility of each analyte. According to the results, the presence of Au2 clusters increased the current density due to electrocatalytic activity compared to the electrode without Au2 clusters. In addition, the Au2 clusters on the modified electrode had a more linear concentration dependency trend than the modified electrode without atomic gold clusters. Finally, the separation among butanol isomers was enhanced using different combination of room-temperature ionic liquids and fixed potentials.

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“…Currently, the common detection methods for gas contain chemical methods and spectroscopic methods. Chemical methods include electrochemical sensors, − chemiluminescent detectors (CLD), − gas chromatography (GC), − and chemiresistive gas sensors. − Among these, the electrochemical sensor is susceptible to other substances in exhaled breath (EB) with a short service life and high maintenance costs. While the CLD is highly sensitive to trace NO gas, it usually requires the use of excessive amounts of a toxic reagent (O 3 ), thereby causing frequent maintenance and calibration.…”

mentioning

confidence: 99%

Ultrasensitive Online NO Sensor Based on a Distributed Parallel Self-Regulating Neural Network and Ultraviolet Differential Optical Absorption Spectroscopy for Exhaled Breath Diagnosis

Zhu,

Gao,

et al. 2024

ACS Sens.

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The concentration of fractional exhaled nitric oxide (FeNO) is closely related to human respiratory inflammation, and the detection of its concentration plays a key role in aiding diagnosing inflammatory airway diseases. In this paper, we report a gas sensor system based on a distributed parallel self-regulating neural network (DPSRNN) model combined with ultraviolet differential optical absorption spectroscopy for detecting ppb-level FeNO concentrations. The noise signals in the spectrum are eliminated by discrete wavelet transform. The DPSRNN model is then built based on the separated multipeak characteristic absorption structure of the UV absorption spectrum of NO. Furthermore, a distributed parallel network structure is built based on each absorption feature region, which is given self-regulating weights and finally trained by a unified model structure. The final self-regulating weights obtained by the model indicate that each absorption feature region contributes a different weight to the concentration prediction. Compared with the regular convolutional neural network model structure, the proposed model has better performance by considering the effect of separated characteristic absorptions in the spectrum on the concentration and breaking the habit of bringing the spectrum as a whole into the model training in previous related studies. Lab-based results show that the sensor system can stably achieve high-precision detection of NO (2.59−750.66 ppb) with a mean absolute error of 0.17 ppb and a measurement accuracy of 0.84%, which is the best result to date. More interestingly, the proposed sensor system is capable of achieving high-precision online detection of FeNO, as confirmed by the exhaled breath analysis.

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Toward Planar Atomic-Gold Decorated Polyaniline Gas Sensors for Enhanced Electrochemical Sensing

Cited by 8 publications

References 28 publications

Unraveling the nature of sensing in electrostatic MEMS gas sensors

Unraveling the nature of sensing in electrostatic MEMS gas sensors

Array of Miniaturized Amperometric Gas Sensors Using Atomic Gold Decorated Pt/PANI Electrodes in Room Temperature Ionic Liquid Films

Ultrasensitive Online NO Sensor Based on a Distributed Parallel Self-Regulating Neural Network and Ultraviolet Differential Optical Absorption Spectroscopy for Exhaled Breath Diagnosis

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