Chemosensors

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9 pages, 1631 KiB

Open AccessCommunication

Polymer-Based High Diffraction Efficiency and High Resolution Volume Holographic Transmission Gratings

by Riccardo Castagna, Andrea Di Donato, Oriano Francescangeli and Daniele Eugenio Lucchetta

Chemosensors 2022, 10(9), 356; https://doi.org/10.3390/chemosensors10090356 - 1 Sep 2022

Cited by 1 | Viewed by 2003

Abstract

We report on the optical characterization of very high-efficiency and high-resolution holographic volume phase transmission gratings. The gratings are recorded in a new photo-polymerizable mixture made by epoxy-resin and multi-acrylate. The epoxy-resin used is known to make tenacious acrylate-based films. The holographic mixture [...] Read more.

We report on the optical characterization of very high-efficiency and high-resolution holographic volume phase transmission gratings. The gratings are recorded in a new photo-polymerizable mixture made by epoxy-resin and multi-acrylate. The epoxy-resin used is known to make tenacious acrylate-based films. The holographic mixture contains two photo-initiators, the synergic effect of which enables a reliable photo-polymerization process in the visible region of the electromagnetic spectrum. The recorded holograms are mechanically stable, show long-term temporal stability and very high values of diffraction efficiency, coupled with good angular selectivity due to a relatively narrow band of wavelengths. We measured the intensity of the transmitted beam and calculated the intensity of the diffracted beam at different wavelengths, deriving the refractive index modulation and the grating pitch by fitting the experimental data with a slightly modified theoretical approach. These kind of mixtures can be used in several fields of application, such as chemical or bio-sensors, high resolution optical sensors, high-density optical data storage, encryption and security. Full article

(This article belongs to the Special Issue Nanomaterials Based on Bio/Chemical Sensors)

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13 pages, 7230 KiB

Open AccessArticle

Effects of Thermal Oxidation on Sensing Properties of Porous Silicon

by Nikola Baran, Sanja Renka, Matea Raić, Davor Ristić and Mile Ivanda

Chemosensors 2022, 10(9), 349; https://doi.org/10.3390/chemosensors10090349 - 25 Aug 2022

Cited by 2 | Viewed by 1786

Abstract

We report the effects of thermal oxidation on the sensing properties of porous silicon. Porous silicon substrates were prepared by electrochemical etching and thermally oxidized at different temperatures. A comparative EDS analysis shows that porous surfaces oxidized at higher temperatures have higher oxygen-to-silicon [...] Read more.

We report the effects of thermal oxidation on the sensing properties of porous silicon. Porous silicon substrates were prepared by electrochemical etching and thermally oxidized at different temperatures. A comparative EDS analysis shows that porous surfaces oxidized at higher temperatures have higher oxygen-to-silicon ratios. Our results indicate that the chemoresistive response due to the presence of isopropanol vapors at room temperature also increases with an increasing oxidation temperature. The presence of oxygen atoms in the PS layer could both protect the sensor from further atmospheric oxidation and increase its sensitivity. Full article

(This article belongs to the Special Issue Nanomaterials Based on Bio/Chemical Sensors)

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11 pages, 2259 KiB

Open AccessArticle

Nanowire Gas Sensor to Support Optical and Volatile Changes in the Production Chain of Fruit Jams

by Estefanía Núñez-Carmona, Giuseppe Greco, Dario Genzardi, Pierpaolo Piccoli, Ivano Zottele, Armando Tamanini, Giorgio Sberveglieri and Veronica Sberveglieri

Chemosensors 2022, 10(9), 345; https://doi.org/10.3390/chemosensors10090345 - 23 Aug 2022

Viewed by 1748

Abstract

The marmalade and jam market is growing worldwide, with the European countries being the main producers in this sector. The market has ancient origins and the production is aimed at conserving the surplus fruits during some period of the year. Nowadays, the automatic [...] Read more.

The marmalade and jam market is growing worldwide, with the European countries being the main producers in this sector. The market has ancient origins and the production is aimed at conserving the surplus fruits during some period of the year. Nowadays, the automatic production processes are wide-ranging but start with high-quality raw materials and follow an appropriate cooking process to conserve the main features of the final product. On the other hand, cases of overcooking may occur which lead to the production of hydroxy-methyl-furfural and derivatives with consequent browning and poor organoleptic characteristics of the final product. This study aimed to use chemical oxide nanowire gas sensors device S3 coupled with optical techniques and recognizing algorithms to create a multi-actor platform able to control the production process of jams and marmalades with a fast response time, to assist the production process and avoid economical losses in the sector. PCA shows that this innovative technology can recognize changes in the volatile fingerprint, distinguishing when the positive and more natural organoleptic characteristics of the fruit are still present from the appearance of the organoleptic defects due to a faulty production process. Full article

(This article belongs to the Special Issue Nanomaterials Based on Bio/Chemical Sensors)

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13 pages, 3537 KiB

Open AccessArticle

A Novel Voltammetric Electronic Tongue Based on Nanocomposites Modified Electrodes for the Discrimination of Red Wines from Different Geographical Origins

by Ziwei Zheng, Shanshan Qiu and Zhenbo Wei

Chemosensors 2022, 10(8), 332; https://doi.org/10.3390/chemosensors10080332 - 13 Aug 2022

Cited by 7 | Viewed by 2116

Abstract

A novel voltammetric electronic tongue (VE-tongue) system based on three nanocomposites modified working electrodes was used for the discrimination of red wine from different geographical origins. The three types of modified working electrodes were fabricated to detect glucose (Glu), tartaric acid (TA), and [...] Read more.

A novel voltammetric electronic tongue (VE-tongue) system based on three nanocomposites modified working electrodes was used for the discrimination of red wine from different geographical origins. The three types of modified working electrodes were fabricated to detect glucose (Glu), tartaric acid (TA), and non-specific flavor information in a red wine sample, respectively. The electrochemical properties of three electrodes were tested by cyclic voltammetric method, and pH, accumulation time, and scan rates were optimized for Glu and TA sensors. Scanning electron microscopy (SEM), X-ray proton spectrum (XPS), and X-ray diffraction (XRD) were used for the characterization of modified materials. This sensor array was then applied to identify four kinds of red wines from different geographical origins, and the multi-frequency and potential steps (STEP) method was used to obtain flavor information regarding rice wines. The classification ability of this VE-tongue system was evaluated by using partial least squares (PLS) regression and principal component analysis (PCA), while back propagation neural network (BPNN), random forest (RF), support vector machines (SVM), deep neural network (DNN), and K-nearest neighbor (KNN) were used for the prediction. The results showed that PCA could explain about the 95.7% of the total variance, and BPNN performed best in the prediction work (the prediction accuracy was 95.8%). Therefore, the VE-tongue system with BPNN was chosen to effectively discriminate red wines from different geographical origins, and the novel VE-tongue aiming at red wine discrimination with high accuracy and lower cost was established. Full article

(This article belongs to the Special Issue Nanomaterials Based on Bio/Chemical Sensors)

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7 pages, 2049 KiB

Open AccessCommunication

HKUST-1-Doped High-Resolution Volume Holographic Gratings

by Riccardo Castagna, Alessia Tombesi, Cristiano Riminesi, Andrea Di Donato, Oriano Francescangeli and Daniele Eugenio Lucchetta

Chemosensors 2022, 10(8), 310; https://doi.org/10.3390/chemosensors10080310 - 5 Aug 2022

Cited by 3 | Viewed by 2080

Abstract

We report on transmission holographic gratings doped with metal organic frameworks (MOFs). As a first attempt, we focused on MOF-199, also known as HKUST-1, which is an efficient adsorbent of VOCs. HKUST-1 is not soluble in the pre-polymerized holographic mixture. For this reason, [...] Read more.

We report on transmission holographic gratings doped with metal organic frameworks (MOFs). As a first attempt, we focused on MOF-199, also known as HKUST-1, which is an efficient adsorbent of VOCs. HKUST-1 is not soluble in the pre-polymerized holographic mixture. For this reason, samples containing HKUST-1 show high light scattering. In this work, the recording of HKUST-1-doped one-dimensional transmission phase gratings is demonstrated. The optical properties of the recorded structures, such as diffraction efficiency and average refractive index changes, are reported by using angular analysis measurements. A first attempt to demonstrate the possibility of using the doped gratings as sensors is also reported. Full article

(This article belongs to the Special Issue Nanomaterials Based on Bio/Chemical Sensors)

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16 pages, 20697 KiB

Open AccessArticle

Design and Evaluation of Low-Power Co₃O₄ Gas Sensing Element as a Part of Cyber Physical Systems

by Marilena Moschogiannaki, George Vardakis, Emmanouil Gagaoudakis, Stefanos Papadakis and Vassilios Binas

Chemosensors 2022, 10(7), 266; https://doi.org/10.3390/chemosensors10070266 - 8 Jul 2022

Viewed by 1689

Abstract

Physical processes working in parallel with digital ones have transformed the way we view systems and have led to the creation of applications that boost the quality of people’s lives, increase security as well as decrease production costs of goods. Critical to this [...] Read more.

Physical processes working in parallel with digital ones have transformed the way we view systems and have led to the creation of applications that boost the quality of people’s lives, increase security as well as decrease production costs of goods. Critical to this evolution is the cost decrease in the components of such systems, among which are gas sensors. In this work, a custom-made Co₃O₄ gas sensing element is presented, which can potentially be used as part of a cyber-physical system (CPS) for O₃ monitoring. To investigate its performance, a CPS is developed using low-cost, low-power micro-controller units (MCUs) and comparisons both with the laboratory equipment and commercial off-the-shelf (COTS) ozone sensors are provided. The experiments show that the Co₃O₄ sensor works at room temperature with low input voltage and low power consumption when used with the proposed MCUs. Moreover, an enhanced gas sensing performance against ozone is observed under low-pressure conditions due to the detection of low ozone concentrations (85.90 ppb) and good sensor response (113.1%) towards 1100 ppb O₃. However, the drawbacks that need improvement relate to the kinetics of the charge carriers, which affect the response time and recovery behavior. The effect of humidity needs to be clarified in further works. Full article

(This article belongs to the Special Issue Nanomaterials Based on Bio/Chemical Sensors)

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9 pages, 1568 KiB

Open AccessArticle

Kinetics of Odorant Recognition with a Graphene-Based Olfactory Receptor Mimicry

by Caroline Bonazza and Klaus Bonazza

Chemosensors 2022, 10(6), 203; https://doi.org/10.3390/chemosensors10060203 - 27 May 2022

Viewed by 1931

Abstract

Malaria vector mosquito species rely on a handful of specific pheromones for mating; one of them, sulcatone (6-methyl-5-hepten-2-one), is also found in human exudation. Therefore, a complete understanding of the insect’s olfaction, and rapid real-time methods for odorant detection, are required. Here, we [...] Read more.

Malaria vector mosquito species rely on a handful of specific pheromones for mating; one of them, sulcatone (6-methyl-5-hepten-2-one), is also found in human exudation. Therefore, a complete understanding of the insect’s olfaction, and rapid real-time methods for odorant detection, are required. Here, we mimic the odorant recognition of the nerve cells of an insect’s antenna with a synthetic graphene-based bio-electro-interfacial odorant receptor. By this means, we obtain the kinetics of the genuine odorant recognition reaction and compare them to electro-antennogram data that represent the more complex scenario of a living insect. The odorant-binding proteins OBP 9A and 9B only associate with their ligands weakly, showing K_Ds of between 2.1 mM and 3 mM, while the binding kinetics of OBP proteins depend on the structural feature of a cystine knot and are modulated by the local milieu within a protein-aided enhancement zone. Full article

(This article belongs to the Special Issue Nanomaterials Based on Bio/Chemical Sensors)

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13 pages, 2844 KiB

Open AccessArticle

Measurement of Pulsating Flow Using a Self-Attachable Flexible Strain Sensor Based on Adhesive PDMS and CNT

by Chaehyun Ryu, Jeonhyeong Park, Soon In Jung, Il Ryu Jang and Hoe Joon Kim

Chemosensors 2022, 10(5), 187; https://doi.org/10.3390/chemosensors10050187 - 16 May 2022

Cited by 6 | Viewed by 3039

Abstract

Accurate monitoring is needed for pulsating flow in many healthcare and bio applications. Specifically, real-time monitoring of pulsating blood flow provides rich information regarding a patient’s health conditions. This paper proposes a flexible strain sensor capable of detecting the pulsating fluid flow by [...] Read more.

Accurate monitoring is needed for pulsating flow in many healthcare and bio applications. Specifically, real-time monitoring of pulsating blood flow provides rich information regarding a patient’s health conditions. This paper proposes a flexible strain sensor capable of detecting the pulsating fluid flow by directly measuring the circumferential strain induced by a rapid change in the flow rate. The thin and flexible strain sensor consists of a polydimethylsiloxane (PDMS) with a Triton-X treatment to enhance the adhesive property and multi-walled carbon nanotubes (MWCNT) as the piezoresistive sensing layer. MWCNT integration implements a simple spray-coating method. The adhesive PDMS/CNT strain sensor exhibits a highly adhesive nature and can be attached to a silicone tube’s curved surface. By analyzing the theoretical modeling based on fluid energy equation and solid mechanics, strains induced on the soft tube by the change in flow rate, viscosity, and fluid density can be predicted. We performed the flow rate measurement at varying fluid-flow rates and liquid viscosities, and the results match our prediction. The sensitivity and limit of detection of the presented strain sensor are about 0.55 %min/L and 0.4 L/min, respectively. Both the calculation and experiment confirm that the sensor resistance is most sensitive to the fluid-flow rate, thus, enabling the accurate tracking of pulsating fluids’ flow rate, regardless of the viscosity or density. Full article

(This article belongs to the Special Issue Nanomaterials Based on Bio/Chemical Sensors)

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12 pages, 3421 KiB

Open AccessArticle

Electrodes for Paracetamol Sensing Modified with Bismuth Oxide and Oxynitrate Heterostructures: An Experimental and Computational Study

by Filippo Franceschini, Mattia Bartoli, Alberto Tagliaferro and Sandro Carrara

Chemosensors 2021, 9(12), 361; https://doi.org/10.3390/chemosensors9120361 - 17 Dec 2021

Cited by 7 | Viewed by 3097

Abstract

In this work, novel platforms for paracetamol sensing were developed by the deposition of Bi₂O₃, Bi₅O₇NO₃ and their heterostructures onto screen-printed carbon-paste electrodes. An easy and scalable solid state synthesis route was employed, and [...] Read more.

In this work, novel platforms for paracetamol sensing were developed by the deposition of Bi₂O₃, Bi₅O₇NO₃ and their heterostructures onto screen-printed carbon-paste electrodes. An easy and scalable solid state synthesis route was employed, and by setting the calcination temperatures at 500 °C and 525 °C we induced the formation of heterostructures of Bi₂O₃ and Bi₅O₇NO₃. Cyclic voltammetry measurements highlighted that the heterostructure produced at 500 °C provided a significant enhancement in performance compared to the monophases of Bi₂O and Bi₅O₇NO₃, respectively. That heterostructure showed a mean peak-to-peak separation

E_{p}

of 411 mV and a sensitivity increment of up to 70% compared to bare electrodes. A computational study was also performed in order to evaluate the geometrical and kinetic parameters of representative clusters of bismuth oxide and subnitrate when they interact with paracetamol. Full article

(This article belongs to the Special Issue Nanomaterials Based on Bio/Chemical Sensors)

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10 pages, 12459 KiB

Open AccessCommunication

Enhanced Capacitive Humidity Sensing Performance at Room Temperature via Hydrogen Bonding of Cyanopyridone-Based Oligothiophene Donor

by Salman Ali, Mohammed A. Jameel, Christopher J. Harrison, Akhil Gupta, Richard A. Evans, Mahnaz Shafiei and Steven J. Langford

Chemosensors 2021, 9(11), 320; https://doi.org/10.3390/chemosensors9110320 - 15 Nov 2021

Cited by 13 | Viewed by 2487

Abstract

Cyanopyridone-based oligothiophene donors with both hydrophobic and hydrophilic characters have been evaluated as active layers within simple capacitive devices for humidity sensing at room temperature. Surface studies using atomic force microscopy revealed a self-assembled nanofibrous network with a thin needle-like structure for the [...] Read more.

Cyanopyridone-based oligothiophene donors with both hydrophobic and hydrophilic characters have been evaluated as active layers within simple capacitive devices for humidity sensing at room temperature. Surface studies using atomic force microscopy revealed a self-assembled nanofibrous network with a thin needle-like structure for the terminal hydroxy example (CP6), devoid in the methyl example (CP1). The sensing performance of each sensor was investigated over a broad range of relative humidity levels as a function of capacitance at room temperature. The sensor CP6 demonstrated favourable features such as high sensitivity (12.2 pF/%RH), quick response/recovery (13 s/20.7 s), wide working range of relative humidity (10%–95% RH), low hysteresis (0.57%), outstanding recyclability, and excellent long-term stability. From the results obtained, hydrophilicity and hydrogen bonding appear to play a vital role in enhancing humidity sensing performance, leading to possible new design directions for simple organic semiconductor-based sensors. Full article

(This article belongs to the Special Issue Nanomaterials Based on Bio/Chemical Sensors)

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12 pages, 3341 KiB

Open AccessArticle

Flexible Wearable Sensors Based in Carbon Nanotubes Reinforced Poly(Ethylene Glycol) Diglycidyl Ether (PEGDGE): Analysis of Strain Sensitivity and Proof of Concept

by Antonio del Bosque, Xoan F. Sánchez-Romate, María Sánchez and Alejandro Ureña

Chemosensors 2021, 9(7), 158; https://doi.org/10.3390/chemosensors9070158 - 25 Jun 2021

Cited by 13 | Viewed by 3215

Abstract

The electromechanical capabilities of carbon nanotube (CNT) doped poly(ethylene glycol) diglycidyl ether (PEGDGE) have been explored. In this regard, the effect of both CNT content and curing conditions were analyzed. The electrical conductivity increased both with CNT content and curing temperature due to [...] Read more.

The electromechanical capabilities of carbon nanotube (CNT) doped poly(ethylene glycol) diglycidyl ether (PEGDGE) have been explored. In this regard, the effect of both CNT content and curing conditions were analyzed. The electrical conductivity increased both with CNT content and curing temperature due to the lower gel time that leads to a lower reaggregation during curing. More specifically, the percolation threshold at 160 and 180 °C curing temperatures is below 0.01 wt.%, and this limit increases up to 0.1 wt.% at 140 °C for an 8 h curing cycle. Moreover, the strain monitoring capabilities were investigated, and the effect of contact resistance was also analyzed. The electrical contacts made with silver ink led to higher values of gauge factor (GF) but presented some issues at very high strains due to their possible detachment during testing. In every case, GF values were far above conventional metallic gauges with a very significant exponential behavior, especially at low CNT content due to a prevalence of tunneling mechanisms. Finally, a proof of concept of fingers and knee motion monitoring was carried out, showing a high sensitivity for human motion sensing. Full article

(This article belongs to the Special Issue Nanomaterials Based on Bio/Chemical Sensors)

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16 pages, 3239 KiB

Open AccessArticle

Thermal and Structural Properties of High Density Polyethylene/Carbon Nanotube Nanocomposites: A Comparison Study

by Ayat Bozeya, Yahia F. Makableh, Rund Abu-Zurayk, Aya Khalaf and Abeer Al Bawab

Chemosensors 2021, 9(6), 136; https://doi.org/10.3390/chemosensors9060136 - 11 Jun 2021

Cited by 16 | Viewed by 4096

Abstract

The effects of functionalization of carbon nanotubes on the properties of nanocomposite sheets prepared from high-density polyethylene (HDPE) and carbon nanotubes (CNTs) were investigated. Carbon nanotubes were first oxidized, followed by amine group functionalization. The Fourier transform-infrared (FTIR) spectroscopy results confirm the presence [...] Read more.

The effects of functionalization of carbon nanotubes on the properties of nanocomposite sheets prepared from high-density polyethylene (HDPE) and carbon nanotubes (CNTs) were investigated. Carbon nanotubes were first oxidized, followed by amine group functionalization. The Fourier transform-infrared (FTIR) spectroscopy results confirm the presence of oxygenated and amide groups at the surface of the CNTs after each treatment. The HDPE/CNT nanocomposites sheets were prepared using a melt compounding method. Six types of CNTs were used; pristine Single-walled Carbon nanotubes (SWCNT) and pristine Multi-walled Carbon nanotubes (MWCNT), oxidized (O-SWCNT and O-MWCNT) and amide (Amide-SWCNT and Amide-MWCNT). All prepared nanocomposite sheets were characterized using Thermal gravimetric analysis (TGA), Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electronic microscope (SEM). TGA results measured increased thermal stability of the polymer with the addition of CNTs, O-MWCNT showed the best enhancement. XRD measurements confirmed that the addition of CNTs did not change the crystal structure of the polymer, although the crystallinity was decreased. The maximum crystallinity decrease resulted from O-SWNTs addition to the polymer matrix. SEM imaging showed that oxidized and functionalized CNTs have more even dispersion in the polymer matrix compared with pristine CNTs. Full article

(This article belongs to the Special Issue Nanomaterials Based on Bio/Chemical Sensors)

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Review

Jump to: Research

29 pages, 9263 KiB

Open AccessReview

Nanocomposites of Carbon Quantum Dots and Graphene Quantum Dots: Environmental Applications as Sensors

by Ajaypal Kaur, Komal Pandey, Ramandeep Kaur, Nisha Vashishat and Manpreet Kaur

Chemosensors 2022, 10(9), 367; https://doi.org/10.3390/chemosensors10090367 - 15 Sep 2022

Cited by 58 | Viewed by 8714

Abstract

Carbon-based quantum dots and their nanocomposites have sparked immense interest for researchers as sensors due to their attractive physico-chemical properties caused by edge effects and quantum confinement. In this review article, we have discussed the synthesis and application of nanocomposites of graphene quantum [...] Read more.

Carbon-based quantum dots and their nanocomposites have sparked immense interest for researchers as sensors due to their attractive physico-chemical properties caused by edge effects and quantum confinement. In this review article, we have discussed the synthesis and application of nanocomposites of graphene quantum dots (GQDs) and carbon quantum dots (CQDs). Different synthetic strategies for CQDs, GQDs, and their nanocomposites, are categorized as top-down and bottom-up approaches which include laser ablation, arc-discharge, chemical oxidation, ultrasonication, oxidative cleavage, microwave synthesis, thermal decomposition, solvothermal or hydrothermal method, stepwise organic synthesis, carbonization from small molecules or polymers, and impregnation. A comparison of methodologies is presented. The environmental application of nanocomposites of CQDs/GQDs and pristine quantum dots as sensors are presented in detail. Their applications envisage important domains dealing with the sensing of pollutant molecules. Recent advances and future perspective in the use of CQDs, GQDs, and their nanocomposites as sensors are also explored. Full article

(This article belongs to the Special Issue Nanomaterials Based on Bio/Chemical Sensors)

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29 pages, 2584 KiB

Open AccessReview

A Critical Review of the Use of Graphene-Based Gas Sensors

by Aniket Chakraborthy, Suresh Nuthalapati, Anindya Nag, Nasrin Afsarimanesh, Md. Eshrat E Alahi and Mehmet Ercan Altinsoy

Chemosensors 2022, 10(9), 355; https://doi.org/10.3390/chemosensors10090355 - 1 Sep 2022

Cited by 21 | Viewed by 5104

Abstract

The employment of graphene for multifunctional uses has been a cornerstone in sensing technology. Due to its excellent electrochemical properties, graphene has been used in its pure and composite forms to detect target molecules over a wide range of surfaces. The adsorption process [...] Read more.

The employment of graphene for multifunctional uses has been a cornerstone in sensing technology. Due to its excellent electrochemical properties, graphene has been used in its pure and composite forms to detect target molecules over a wide range of surfaces. The adsorption process on the graphene-based sensors has been studied in terms of the change in resistance and capacitance values for various industrial and environmental applications. This paper highlights the performance of graphene-based sensors for detecting different kinds of domestic and industrial gases. These graphene-based gas sensors have achieved enhanced output in terms of sensitivity and working range due to specific experimental parameters, such as elevated temperature, presence of particular gas-specific layers and integration with specific nanomaterials that assist with the adsorption of gases. The presented research work has been classified based on the physical nature of graphene used in conjugation with other processed materials. The detection of five different types of gases, including carbon dioxide (CO₂), ammonia (NH₃), hydrogen sulphide (H₂S), nitrogen dioxide (NO₂) and ethanol (C₂H₅OH) has been shown in the paper. The challenges of the current graphene-based gas sensors and their possible remedies have also been showcased in the paper. Full article

(This article belongs to the Special Issue Nanomaterials Based on Bio/Chemical Sensors)

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25 pages, 2005 KiB

Open AccessReview

Recent Advances of Nanostructured Materials for Photoelectrochemical Bioanalysis

by Ling Zhang, Yuan-Cheng Zhu and Wei-Wei Zhao

Chemosensors 2022, 10(1), 14; https://doi.org/10.3390/chemosensors10010014 - 30 Dec 2021

Cited by 9 | Viewed by 3961

Abstract

Nowadays, the emerging photoelectrochemical (PEC) bioanalysis has drawn intensive interest due to its numerous merits. As one of its core elements, functional nanostructured materials play a crucial role during the construction of PEC biosensors, which can not only be employed as transducers but [...] Read more.

Nowadays, the emerging photoelectrochemical (PEC) bioanalysis has drawn intensive interest due to its numerous merits. As one of its core elements, functional nanostructured materials play a crucial role during the construction of PEC biosensors, which can not only be employed as transducers but also act as signal probes. Although both chemical composition and morphology control of nanostructured materials contribute to the excellent analytical performance of PEC bioassay, surveys addressing nanostructures with different dimensionality have rarely been reported. In this review, according to classification based on dimensionality, zero-dimensional, one-dimensional, two-dimensional, and three-dimensional nanostructures used in PEC bioanalysis are evaluated, with an emphasis on the effect of morphology on the detection performances. Furthermore, using the illustration of recent works, related novel PEC biosensing patterns with promising applications are also discussed. Finally, the current challenges and some future perspectives in this field are addressed based on our opinions. Full article

(This article belongs to the Special Issue Nanomaterials Based on Bio/Chemical Sensors)

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29 pages, 13389 KiB

Open AccessReview

Fluoro-Substituted Metal Phthalocyanines for Active Layers of Chemical Sensors

by Darya Klyamer, Dmitry Bonegardt and Tamara Basova

Chemosensors 2021, 9(6), 133; https://doi.org/10.3390/chemosensors9060133 - 8 Jun 2021

Cited by 28 | Viewed by 4097

Abstract

Metal phthalocyanines bearing electron-withdrawing fluorine substituents were synthesized a long time ago, but interest in the study of their films has emerged in recent decades. This is due to the fact that, unlike unsubstituted phthalocyanines, films of some fluorinated phthalocyanines exhibit the properties [...] Read more.

Metal phthalocyanines bearing electron-withdrawing fluorine substituents were synthesized a long time ago, but interest in the study of their films has emerged in recent decades. This is due to the fact that, unlike unsubstituted phthalocyanines, films of some fluorinated phthalocyanines exhibit the properties of n-type semiconductors, which makes them promising candidates for application in ambipolar transistors. Apart from this, it was shown that the introduction of fluorine substituents led to an increase in the sensitivity of phthalocyanine films to reducing gases. This review analyzes the state of research over the last fifteen years in the field of applications of fluoro-substituted metal phthalocyanines as active layers of gas sensors, with a primary focus on chemiresistive ones. The active layers on the basis of phthalocyanines with fluorine and fluorine-containing substituents of optical and quartz crystal microbalance sensors are also considered. Attention is paid to the analysis of the effect of molecular structure (central metal, number and type of fluorine substituent etc.) on sensor properties of fluorinated phthalocyanine films. Full article

(This article belongs to the Special Issue Nanomaterials Based on Bio/Chemical Sensors)

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