Research

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13 pages, 2872 KiB

Open AccessArticle

Characterization of Flexible Copper Selenide Films on Polyamide Substrate Obtained by SILAR Method—Towards Application in Electronic Devices

by Gediminas Jakubauskas, Martina Gilic, Edita Paluckiene, Jelena Mitric, Jovana Cirkovic, Uros Ralevic, Egle Usoviene, Egidijus Griskonis and Neringa Petrasauskiene

Chemosensors 2022, 10(8), 313; https://doi.org/10.3390/chemosensors10080313 - 05 Aug 2022

Cited by 4 | Viewed by 1695

Abstract

Thin copper selenide films were synthesized on polyamide sheets using the successive ionic layer adsorption and reaction (SILAR) method at three different temperatures. It was found that elevating the temperature of the solution led to the creation of copper selenide films with different [...] Read more.

Thin copper selenide films were synthesized on polyamide sheets using the successive ionic layer adsorption and reaction (SILAR) method at three different temperatures. It was found that elevating the temperature of the solution led to the creation of copper selenide films with different features. X-ray diffraction characterization revealed that all films crystallized into a cubic Cu_2−xSe, but with different crystallinity parameters. With elevating the temperature, grain size increased (6.61–14.33 and 15.81 for 40, 60 and 80 °C, respectively), while dislocation density and the strain decreased. Surface topology was investigated with Scanning Electron Microscopy and Atomic Force Microscopy, which revealed that the grains combined into agglomerates of up to 100 nm (80 °C) to 1 μm (40 °C). The value of the direct band gap of the copper selenide thin films, obtained with UV/VIS spectroscopy, varied in the range of 2.28–1.98 eV. The formation of Cu_2−xSe was confirmed by Raman analysis; the most prominent Raman peak is located at 260 cm⁻¹, which is attributed to binary copper selenides. The thin Cu_2−xSe films deposited on polyamide showed p-type conductivity, and the electrical resistivity varied in the range of 20–50 Ω. Our results suggest that elevated temperatures prevent large agglomeration, leading to higher resistance behavior. Full article

(This article belongs to the Special Issue Nanomaterials-Based Sensors)

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11 pages, 3095 KiB

Open AccessArticle

Real-Time Fluorescence Imaging of His-Tag-Driven Conjugation of mCherry Proteins to Silver Nanowires

by Martyna Jankowska, Karolina Sulowska, Kamil Wiwatowski, Joanna Niedziółka-Jönsson and Sebastian Mackowski

Chemosensors 2022, 10(4), 149; https://doi.org/10.3390/chemosensors10040149 - 18 Apr 2022

Cited by 1 | Viewed by 2123

Abstract

In this work, we aimed to apply fluorescence microscopy to image protein conjugation to Ni-NTA modified silver nanowires in real time via the His-tag attachment. First, a set of experiments was designed and performed for the mixtures of proteins and silver nanowires in [...] Read more.

In this work, we aimed to apply fluorescence microscopy to image protein conjugation to Ni-NTA modified silver nanowires in real time via the His-tag attachment. First, a set of experiments was designed and performed for the mixtures of proteins and silver nanowires in order to demonstrate plasmon enhancement of mCherry protein fluorescence as well as the ability to image fluorescence of single molecules. The results indicated strong enhancement of single-protein fluorescence emission upon coupling with silver nanowires. This conclusion was supported by a decrease in the fluorescence decay time of mCherry proteins. Real-time imaging was carried out for a structure created by dropping protein solution onto a glass substrate with functionalized silver nanowires. We observed specific attachment of mCherry proteins to the nanowires, with the recognition time being much longer than in the case of streptavidin–biotin conjugation. This result indicated that it is possible to design a universal and efficient real-time sensing platform with plasmonically active functionalized silver nanowires. Full article

(This article belongs to the Special Issue Nanomaterials-Based Sensors)

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13 pages, 5857 KiB

Open AccessArticle

Decoration of Ag Nanoparticle on ZnO Nanowire by Intense Pulsed Light and Enhanced UV Photodetector

by Youngwook Noh, Jaehak Shin, Horim Lee, Gyu Young Kim, Manoj Kumar and Dongjin Lee

Chemosensors 2021, 9(11), 321; https://doi.org/10.3390/chemosensors9110321 - 15 Nov 2021

Cited by 7 | Viewed by 2255

Abstract

Zinc oxide (ZnO) nanowires (NWs) are wide-bandgap semiconductors that absorb ultraviolet (UV) radiation. Various post-treatment processes have been studied to improve the optical properties of the as-grown ZnO NWs. Among them, Ag nanoparticles (NPs) effectively improved the optical properties on the surface of [...] Read more.

Zinc oxide (ZnO) nanowires (NWs) are wide-bandgap semiconductors that absorb ultraviolet (UV) radiation. Various post-treatment processes have been studied to improve the optical properties of the as-grown ZnO NWs. Among them, Ag nanoparticles (NPs) effectively improved the optical properties on the surface of the ZnO NWs. In this study, ZnO NWs were synthesized via the hydrothermal synthesis method. ZnO NWs were decorated with Ag NPs on the surface of the ZnO NWs in a silver nitrate (AgNO₃) aqueous solution by intense pulsed light (IPL) irradiation. Ag NPs were successfully decorated under the following conditions: aqueous AgNO₃ solution of 100 nM, an energy of 1 J/cm², and an exposure time of 8 ms. The responsivity and sensitivity of the ZnO NW UV photodetectors increased by 7.43 and 3.37 times, respectively. The IPL process makes it possible to decorate Ag NPs in a simple manner within an extremely short time. Full article

(This article belongs to the Special Issue Nanomaterials-Based Sensors)

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13 pages, 3668 KiB

Open AccessArticle

Optimization of ZnO Nanorods Concentration in a Micro-Structured Polymeric Composite for Nanogenerators

by Andreia dos Santos, Filipe Sabino, Ana Rovisco, Pedro Barquinha, Hugo Águas, Elvira Fortunato, Rodrigo Martins and Rui Igreja

Chemosensors 2021, 9(2), 27; https://doi.org/10.3390/chemosensors9020027 - 31 Jan 2021

Cited by 11 | Viewed by 3788

Abstract

The growing use of wearable devices has been stimulating research efforts in the development of energy harvesters as more portable and practical energy sources alternatives. The field of piezoelectric nanogenerators (PENGs) and triboelectric nanogenerators (TENGs), especially employing zinc oxide (ZnO) nanowires (NWs), has [...] Read more.

The growing use of wearable devices has been stimulating research efforts in the development of energy harvesters as more portable and practical energy sources alternatives. The field of piezoelectric nanogenerators (PENGs) and triboelectric nanogenerators (TENGs), especially employing zinc oxide (ZnO) nanowires (NWs), has greatly flourished in recent years. Despite its modest piezoelectric coefficient, ZnO is very attractive due to its sustainable raw materials and the facility to obtain distinct morphologies, which increases its multifunctionality. The integration of ZnO nanostructures into polymeric matrices to overcome their fragility has already been proven to be fruitful, nevertheless, their concentration in the composite should be optimized to maximize the harvesters’ output, an aspect that has not been properly addressed. This work studies a composite with variable concentrations of ZnO nanorods (NRs), grown by microwave radiation assisted hydrothermal synthesis, and polydimethylsiloxane (PDMS). With a 25 wt % ZnO NRs concentration in a composite that was further micro-structured through laser engraving for output enhancement, a nanogenerator (NG) was fabricated with an output of 6 V at a pushing force of 2.3 N. The energy generated by the NG could be stored and later employed to power small electronic devices, ultimately illustrating its potential as an energy harvesting device. Full article

(This article belongs to the Special Issue Nanomaterials-Based Sensors)

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12 pages, 1495 KiB

Open AccessArticle

Combining Chemical Functionalization and FinFET Geometry for Field Effect Sensors as Accessible Technology to Optimize pH Sensing

by Dipti Rani, Serena Rollo, Wouter Olthuis, Sivashankar Krishnamoorthy and César Pascual García

Chemosensors 2021, 9(2), 20; https://doi.org/10.3390/chemosensors9020020 - 21 Jan 2021

Cited by 10 | Viewed by 2692

Abstract

Field Effect Transistors (FETs) have led the progress of applications measuring the acidity in aqueous solutions thanks to their accuracy, ease of miniaturization and capacity of multiplexing. The signal-to-noise ratio and linearity of the sensors are two of the most relevant figures of [...] Read more.

Field Effect Transistors (FETs) have led the progress of applications measuring the acidity in aqueous solutions thanks to their accuracy, ease of miniaturization and capacity of multiplexing. The signal-to-noise ratio and linearity of the sensors are two of the most relevant figures of merit that can facilitate the improvements of these devices. In this work we present the functionalization with aminopropyltriethoxysilane (APTES) of a promising new FET design consisting of a high height-to-width aspect ratio with an efficient 2D gating architecture that improves both factors. We measured the transistor transfer and output characteristics before and after APTES functionalization, obtaining an improved sensitivity and linearity in both responses. We also compared the experimental results with a site-biding model of the surface buffering capacity of the APTES functionalized layers. Full article

(This article belongs to the Special Issue Nanomaterials-Based Sensors)

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10 pages, 3755 KiB

Open AccessArticle

Detection of Mackerel Fish Spoilage with a Gas Sensor Based on One Single SnO₂ Nanowire

by Matteo Tonezzer

Chemosensors 2021, 9(1), 2; https://doi.org/10.3390/chemosensors9010002 - 23 Dec 2020

Cited by 13 | Viewed by 2938

Abstract

A chemosensor consisting of one single tin oxide nanowire is used to determine the freshness status of mackerel fish (Scomber scombrus) in a quick and non-invasive way. The tiny chemoresistive sensor is first tested with pure ammonia and then used to measure the [...] Read more.

A chemosensor consisting of one single tin oxide nanowire is used to determine the freshness status of mackerel fish (Scomber scombrus) in a quick and non-invasive way. The tiny chemoresistive sensor is first tested with pure ammonia and then used to measure the total volatile basic nitrogen from different samples of fish at different degrees of freshness. The sensor has proved capable of determining the freshness of a sample in few seconds compared to traditional methods such as microbial count and chromatography, which take hours. The sensor response is well correlated with the total viable count (TVC), proving that the total volatile basic nitrogen is a good way to quickly test the bacterial population in the sample. After calibrating the sensor (following the degradation of the fish during almost two days), it has been tested with random double blind samples, proving that it can well discriminate the degree of freshness of the fish preserved at different temperatures. Full article

(This article belongs to the Special Issue Nanomaterials-Based Sensors)

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Review

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43 pages, 7826 KiB

Open AccessReview

Coupled Multiphysics Modelling of Sensors for Chemical, Biomedical, and Environmental Applications with Focus on Smart Materials and Low-Dimensional Nanostructures

by Sundeep Singh and Roderick Melnik

Chemosensors 2022, 10(5), 157; https://doi.org/10.3390/chemosensors10050157 - 25 Apr 2022

Cited by 2 | Viewed by 2642

Abstract

Low-dimensional nanostructures have many advantages when used in sensors compared to the traditional bulk materials, in particular in their sensitivity and specificity. In such nanostructures, the motion of carriers can be confined from one, two, or all three spatial dimensions, leading to their [...] Read more.

Low-dimensional nanostructures have many advantages when used in sensors compared to the traditional bulk materials, in particular in their sensitivity and specificity. In such nanostructures, the motion of carriers can be confined from one, two, or all three spatial dimensions, leading to their unique properties. New advancements in nanosensors, based on low-dimensional nanostructures, permit their functioning at scales comparable with biological processes and natural systems, allowing their efficient functionalization with chemical and biological molecules. In this article, we provide details of such sensors, focusing on their several important classes, as well as the issues of their designs based on mathematical and computational models covering a range of scales. Such multiscale models require state-of-the-art techniques for their solutions, and we provide an overview of the associated numerical methodologies and approaches in this context. We emphasize the importance of accounting for coupling between different physical fields such as thermal, electromechanical, and magnetic, as well as of additional nonlinear and nonlocal effects which can be salient features of new applications and sensor designs. Our special attention is given to nanowires and nanotubes which are well suited for nanosensor designs and applications, being able to carry a double functionality, as transducers and the media to transmit the signal. One of the key properties of these nanostructures is an enhancement in sensitivity resulting from their high surface-to-volume ratio, which leads to their geometry-dependant properties. This dependency requires careful consideration at the modelling stage, and we provide further details on this issue. Another important class of sensors analyzed here is pertinent to sensor and actuator technologies based on smart materials. The modelling of such materials in their dynamics-enabled applications represents a significant challenge as we have to deal with strongly nonlinear coupled problems, accounting for dynamic interactions between different physical fields and microstructure evolution. Among other classes, important in novel sensor applications, we have given our special attention to heterostructures and nucleic acid based nanostructures. In terms of the application areas, we have focused on chemical and biomedical fields, as well as on green energy and environmentally-friendly technologies where the efficient designs and opportune deployments of sensors are both urgent and compelling. Full article

(This article belongs to the Special Issue Nanomaterials-Based Sensors)

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41 pages, 15347 KiB

Open AccessEditor’s ChoiceReview

Metal–Oxide Nanowire Molecular Sensors and Their Promises

by Hao Zeng, Guozhu Zhang, Kazuki Nagashima, Tsunaki Takahashi, Takuro Hosomi and Takeshi Yanagida

Chemosensors 2021, 9(2), 41; https://doi.org/10.3390/chemosensors9020041 - 22 Feb 2021

Cited by 27 | Viewed by 5623

Abstract

During the past two decades, one–dimensional (1D) metal–oxide nanowire (NW)-based molecular sensors have been witnessed as promising candidates to electrically detect volatile organic compounds (VOCs) due to their high surface to volume ratio, single crystallinity, and well-defined crystal orientations. Furthermore, these unique physical/chemical [...] Read more.

During the past two decades, one–dimensional (1D) metal–oxide nanowire (NW)-based molecular sensors have been witnessed as promising candidates to electrically detect volatile organic compounds (VOCs) due to their high surface to volume ratio, single crystallinity, and well-defined crystal orientations. Furthermore, these unique physical/chemical features allow the integrated sensor electronics to work with a long-term stability, ultra-low power consumption, and miniature device size, which promote the fast development of “trillion sensor electronics” for Internet of things (IoT) applications. This review gives a comprehensive overview of the recent studies and achievements in 1D metal–oxide nanowire synthesis, sensor device fabrication, sensing material functionalization, and sensing mechanisms. In addition, some critical issues that impede the practical application of the 1D metal–oxide nanowire-based sensor electronics, including selectivity, long-term stability, and low power consumption, will be highlighted. Finally, we give a prospective account of the remaining issues toward the laboratory-to-market transformation of the 1D nanostructure-based sensor electronics. Full article

(This article belongs to the Special Issue Nanomaterials-Based Sensors)

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