Detection of cadmium ions Byg-C3N4 functionalization on AlGaN/GaN high electron mobility transistor
05 Nov 2020-Vol. 2265, Iss: 1, pp 030216
TL;DR: In this paper, a novel, highly sensitive AlGaN/GaN high electron mobility transistor (HEMT) sensor is demonstrated for the detection of cadmium ions by the functionalization of graphitic carbon nitride (g-C3N4).
Abstract: In this study, a novel, highly sensitive AlGaN/ GaN high electron mobility transistor (HEMT) sensor is demonstrated for the detection of cadmium ions by the functionalization of graphitic carbon nitride (g-C3N4). The preparation of g-C3N4 was done using the pyrolysis process of urea. The prepared g-C3N4 was functionalized on Au gated AlGaN/ GaN HEMT and the sensing performance was observed by the measurement of electrical characteristics of the device. The sensitivity and limit of detection of the modified g-C3N4 based AlGaN/ GaN HEMT sensor was observed as 0.2606 µA/ppb and 0.533 ppb respectively. The observed limit of detection is very low than the standard guideline values of World Health Organization (WHO) for drinking water. Furthermore, using AlGaN/GaN HEMT theory, we show that the sensing response is very fast due to the availability of 2-D electron gas (2DEG) and very sensitive due to the change in gate potential. The mechanism suggests that the decrement in the drain current was due to the reduction of Cd2+ ions on the g-C3N4 surface which generates negative redox potential at the gate terminal while exposing the functionalized HEMT to Cd2+ ions. Hence, a simple, miniaturized, sensitive and real-time sensor has been developed using AlGaN/GaN HEMT functionalized by g-C3N4 to detect Cd2+ ions in an aqueous environment.
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TL;DR: In this article, the authors introduce the recent trends in heavy metal ion sensing with semiconductor devices, including ion-sensitive field effect transistors (ISFETs) and AlGaN/GaN high electron mobility transistors(HEMTs) and semiconductor materials like graphene, two-dimensional metal dichalcogenides, decorated with different nanoparticles with appropriate functionalization.
Abstract: Heavy metal ions are highly toxic, carcinogens, and non-biodegradable in nature and pollute most water resources that lead to severe health-related issues. It is essential to develop highly sensitive, selective, rapid, and accurate approaches for their detection in water. Semiconducting devices and materials with micro and nanostructures have been featured with fast response time, low power, high sensitivity, low detection limit. This review concisely introduces the recent trends in heavy metal ion sensing with semiconductor devices, including ion-sensitive field-effect transistors (ISFETs) and AlGaN/GaN high electron mobility transistors (HEMTs) and semiconductor materials like graphene, two-dimensional metal dichalcogenides, decorated with different nanoparticles with appropriate functionalization.
20 citations
TL;DR: In this article , the authors have demonstrated a highly sensitive platform for real-time detection of mercury (Hg 2+ ) ions after successfully making silver nanowires (AgNWs)-MoS.
Abstract: We have demonstrated a highly sensitive novel platform for real-time detection of mercury (Hg 2+ ) ions after successfully making silver nanowires (AgNWs)-MoS 2 nanocomposite and functionalizing it over ungated AlGaN/GaN high-electron-mobility transistor (HEMT). The AlGaN/GaN HEMT structures were grown over the sapphire substrate using molecular beam epitaxy. AgNWs-MoS 2 nanocomposites were optimized for the device functionalization and 1:4 ratio was found highly sensitive for Hg 2+ ions. The sensor exhibits high sensitivity toward Hg 2+ ions of 1.604 mA/ppb and calculated its Limit of Detection (LoD) up to the range of 20 parts per trillion. The observed sensitivity is highest among previously reported AlGaN/GaN fabricated HEMT-based sensors for mercury (Hg 2+ ) ions detection and is well below the standard permissible limits as set by World Health Organization (WHO) and Environmental Protection Agency (EPA). The enhancement in sensitivity is due to the enhanced surface to volume ratio of AgNW-MoS 2 nanocomposite and the highly conductive nature of AgNWs incorporated in MoS 2 . Moreover, we also performed sensing on real water samples of tap water and lake water. Furthermore, we showed the smart sensing capability of our developed sensor by illustrating the Internet of Things (IoT)-enabled system for next-generation heavy metal ion sensing.
3 citations
TL;DR: In this paper , the authors present a review on possible approaches including optical (absorbance, fluorescence, colorimetric, X-ray fluorescence and chemiluminescence), electrochemical (ASV, CSV, CV, EIS, and chronoamperometry), electrical, biological, and surface-sensing (SPR and SERS), as candidates for developing such platforms.
Abstract: Water quality monitoring has become more critical in recent years to ensure the availability of clean and safe water from natural aquifers and to understand the evolution of water contaminants across time and space. The conventional water monitoring techniques comprise of sample collection, preservation, preparation, tailed by laboratory testing and analysis with cumbersome wet chemical routes and expensive instrumentation. Despite the high accuracy of these methods, the high testing costs, laborious procedures, and maintenance associated with them don't make them lucrative for end end-users and field testing. As the participation of ultimate stakeholders, that is, common man for water quality and quantity can play a pivotal role in ensuring the sustainability of our aquifers, thus it is essential to develop and deploy portable and user-friendly technical systems for monitoring water sources in real-time or on-site. The present review emphasizes here on possible approaches including optical (absorbance, fluorescence, colorimetric, X-ray fluorescence, chemiluminescence), electrochemical (ASV, CSV, CV, EIS, and chronoamperometry), electrical, biological, and surface-sensing (SPR and SERS), as candidates for developing such platforms. The existing developments, their success, and bottlenecks are discussed in terms of various attributes of water to escalate the essentiality of water quality devices development meeting ASSURED criterion for societal usage. These platforms are also analyzed in terms of their market potential, advancements required from material science aspects, and possible integration with IoT solutions in alignment with Industry 4.0 for environmental application.
3 citations
References
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TL;DR: This paper aims to inspire readers to search for further new applications for this material in catalysis and in other fields by describing the methods used for synthesizing this material with different textural structures and surface morphologies.
Abstract: Graphitic carbon nitride, g-C3N4, is a polymeric material consisting of C, N, and some impurity H, connected via tris-triazine-based patterns. Compared with the majority of carbon materials, it has electron-rich properties, basic surface functionalities and H-bonding motifs due to the presence of N and H atoms. It is thus regarded as a potential candidate to complement carbon in material applications. In this review, a brief introduction to g-C3N4 is given, the methods used for synthesizing this material with different textural structures and surface morphologies are described, and its physicochemical properties are referred. In addition, four aspects of the applications of g-C3N4 in catalysis are discussed: (1) as a base metal-free catalyst for NO decomposition, (2) as a reference material in differentiating oxygen activation sites for oxidation reactions over supported catalysts, (3) as a functional material to synthesize nanosized metal particles, and (4) as a metal-free catalyst for photocatalysis. Th...
919 citations
TL;DR: A simple, label-free colorimetric method using AuNPs accompanied by GSH in a high-salt environment to detect Cd(2+) in water and digested rice samples is reported.
Abstract: A simple and label-free colorimetric method for cadmium ions (Cd2+) detection using unmodified gold nanoparticles (AuNPs) is reported. The unmodified AuNPs easily aggregate in a high concentration of NaCl solution, but the presence of glutathione (GSH) can prevent the salt-induced aggregation of AuNPs. When Cd2+ is added to the stable mixture of AuNPs, GSH, and NaCl, Cd2+ can coordinate with 4× GSH as a spherical shaped complex, which decreases the amount of free GSH on the surface of gold nanoparticles to weaken the stability of AuNPs, and AuNPs will easily aggregate in high-salt conditions. On the basis of the mechanism, we design a simple, label-free colorimetric method using AuNPs accompanied by GSH in a high-salt environment to detect Cd2+ in water and digested rice samples.
175 citations
TL;DR: A new integrated paper based cadmium (Cd(2+)) immunosensing system in lateral flow format, which integrates the sample treatment process with the analyte detection process and the detection and quantification limits found were 0.1 and 0.4 ppb, respectively, these being the lowest limits reported up to now for metal sensors based on paper.
Abstract: Nowadays, the development of systems, devices, or methods that integrate several process steps into one multifunctional step for clinical, environmental, or industrial purposes constitutes a challenge for many ongoing research projects. Here, we present a new integrated paper based cadmium (Cd(2+)) immunosensing system in lateral flow format, which integrates the sample treatment process with the analyte detection process. The principle of Cd(2+) detection is based on competitive reaction between the cadmium-ethylenediaminetetraacetic acid-bovine serum albumin-gold nanoparticles (Cd-EDTA-BSA-AuNP) conjugate deposited on the conjugation pad strip and the Cd-EDTA complex formed in the analysis sample for the same binding sites of the 2A81G5 monoclonal antibody (mAb), specific to Cd-EDTA but not Cd(2+) free, which is immobilized onto the test line. This platform operates without any sample pretreatment step for Cd(2+) detection thanks to an extra conjugation pad that ensures Cd(2+) complexation with EDTA and interference masking through ovalbumin (OVA). The detection and quantification limits found for the device were 0.1 and 0.4 ppb, respectively, these being the lowest limits reported up to now for metal sensors based on paper. The accuracy of the device was evaluated by addition of known quantities of Cd(2+) to different drinking water samples and subsequent Cd(2+) content analysis. Sample recoveries ranged from 95 to 105% and the coefficient of variation for the intermediate precision assay was less than 10%. In addition, the results obtained here were compared with those obtained with the well-established inductively coupled plasma emission spectroscopy (ICPES) and the analysis of certificate standard samples.
126 citations
TL;DR: In this paper, the authors used a combination of bare Au gated and thioglycolic acid functionalized Au-gated AlGaN∕GaN high electron mobility transistors (HEMTs) to detect mercury (II) ions.
Abstract: Bare Au gated and thioglycolic acid functionalized Au-gated AlGaN∕GaN high electron mobility transistors (HEMTs) were used to detect mercury (II) ions. Fast detection of less than 5s was achieved for thioglycolic acid functionalized sensors. This is the shortest response time ever reported for mercury detection. Thioglycolic acid functionalized Au-gated AlGaN∕GaN HEMT based sensors showed 2.5 times larger response than bare Au-gated based sensors. The sensors were able to detect mercury (II) ion concentration as low as 10−7M. The sensors showed an excellent sensing selectivity of more than 100 for detecting mercury ions over sodium or magnesium ions. The dimensions of the active area of the sensor and the entire sensor chip are 50×50μm2 and 1×5mm2, respectively. Therefore, portable, fast response, and wireless based heavy metal ion detectors can be realized with AlGaN∕GaN HEMT based sensors.
86 citations
TL;DR: An electrochemical sensor for the detection of cadmium ions is described using immobilized glutathione as a selective ligand, being stable for more than 16 repeated uses and more than two weeks if used once a day.
Abstract: An electrochemical sensor for the detection of cadmium ions is described using immobilized glutathione as a selective ligand. First, a self-assembled monolayer of 3-mercaptopropionic acid (MPA) was formed on a gold electrode. The carboxyl terminus then allowed attachment of glutathione (GSH)
via carbodiimide coupling to give the MPA–GSH modified electrode. A cadmium ion forms a complex with glutathione via the free sulfhydryl group and also to the carboxyl groups. The complexed ion is reduced by linear and Osteryoung square wave voltammetry with a detection limit of 5 nM. The effect of the kinetics of accumulation of cadmium on the measured current was investigated and modeled. Increasing the temperature of accumulation and electrochemical analysis caused an increase in the voltammetric peak of approximately 4% per °C around room temperature. The modified electrode could be regenerated, being stable for more than 16 repeated uses and more than two weeks if used once a day. Some interference from Pb2+ and Cu2+ was observed but the effects of Zn2+, Ni2+, Cr3+ and Ba2+ were insignificant.
81 citations