Biodegradable adhesives, unlike their traditional counterparts, are engineered to bond to biological tissues while naturally degraded over time, thereby eliminating the need for removal procedures and reducing the risk of chronic inflammation. These unique features are particularly suitable for temporary biomedical applications such as wound closure, internal sealing, or integration with electronics for active/passive functions. The adhesive performance arises from the strategic combination of biodegradable polymers and adhesion mechanisms that dynamically interact with tissue surfaces. This review introduces recent advancements in biodegradable adhesives through a mechanism-based framework, focusing on five key adhesion strategies: physical interlocking, hydrogen bonding, catechol chemistry, amine-carboxyl coupling, and covalent bonding via diazirine or isocyanate linkages. For each strategy, representative material systems, functional properties, and biomedical implementations that enable strong, conformal adhesion under wet and physiological environments are highlighted, and with a discussion of current challenges and future directions toward intelligent, multifunctional bioadhesives for clinical uses are concluded.

Biodegradable polymers have been employed as encapsulants for transient, resorbable implantable devices due to moderate water permeability, mechanical flexibility, and biocompatibility, however most of them relatively lack inherent anti-biofouling properties. This limitation can lead to undesired protein adsorption, cell adhesion, and fibrotic encapsulation, compromising device function and biocompatibility, particularly for long-term implantation scenarios. Here, this study introduces a soft, stretchable, and anti-biofouling encapsulant engineered by integrating self-assembled organosilicon nanowire networks onto micropatterned biodegradable elastomers. The resulting hierarchical surface architecture imparts superhydrophobicity while preserving mechanical integrity, improving water barrier performance by up to 420% compared to unmodified films and retaining stability under cyclic strains. Integration into a transient, stretchable optoelectronic device enables prolonged operation in aqueous environments, and in vitro and in vivo evaluations demonstrate suppressed cell adhesion, reduced fibrotic tissue formation, and excellent biocompatibility, highlighting the potential for long-lasting, bioresorbable electronic implants.

Heavy metal poisoning, particularly Hg(II), poses severe threats to humans and disrupts ecological balance. Heavy metal detection employing electrochemical methods offers several advantages; however, due to the weak electrochemical activity of the glassy carbon electrode (GCE), modification is indispensable. In the present investigation, the GCE was modified with Pr-doped Ce0.2Gd0.2Sm0.2Y0.2Zr0.2O2-δ (HEO) nanoparticles for the electrochemical detection of Hg(II). Samples with varying dopant concentrations were prepared by solution combustion synthesis utilizing glycine as the fuel. The prepared nanoparticles were used to modify the glassy carbon electrode (GCE), and their electrochemical properties were explored towards Hg(II) sensing. The results indicate that modifying the GCE with Pr-doped HEO nanoparticles improved the electrochemical properties. Additionally, the use of such modified electrode material to detect trace amounts of Hg(II) showed a good linear range between concentrations of 1–5 nM with an limit of detection (LOD) of 0.15 nM. Moreover, the modified electrode material exhibited good reproducibility, stability, and anti-interfering properties. Finally, the use of modified sensors for real-time practical applications such as tap water, soil, coffee, and tea extracts showed consistent results, making them a suitable electrode material.

The discovery of non-toxic, bioresorbable silicon electronics is a major breakthrough in the fields of transient, dissolvable biomedical implants and environmental monitors, as it opens up the possibility of producing versatile components based on established semiconductor processes. However, given the limited lifespan of such electronics, it is essential to consider economical manufacturing and production strategies that reduce the unit price for commercialization. Here, we introduce a solution-processable and photo-patternable approach that is facile, cost-effective, and widely accessible for a monolithic 3D fabrication of soft, stretchable, and transient electronics. Optimized chemical synthesis and rational materials engineering yield biodegradable/biocompatible organic insulators, semiconductors, and conductors that can be layered/assembled in sophisticated configurations without impairing underlying components. Direct solution-casting of the materials enables the fabrication of sensors with various modalities and transistors. In vivo implantation of soft, conformable electrode arrays into the brain and heart of animal models demonstrates spatiotemporal electrophysiological monitoring (electroencephalography and electrocardiography) and therapeutic interventions (epileptic seizure suppression and cardiac pacing), highlighting the broad applicability in diverse bio-integrated electronic systems.

Although fast-paced ongoing industrial growth, on the one hand, enhances the lifestyle of the population, on the other hand, it affects human health and the environment as a result of the discharge of pollutants. To address this, designing a novel and effective photocatalyst is necessary to mitigate increasing environmental pollutants. In the present work, we aim to synthesize a single-phase high-entropy zirconate pyrochlore oxide (Ce0.2Pr0.2Zn0.2Nd0.2Tb0.2)2Zr2O7 using a modified Pechini method. The physicochemical properties of the prepared nanoparticles were investigated using X-ray diffraction, UV-visible spectroscopy, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy. The photocatalytic properties were examined using cationic dye (methylene blue), anionic dye (Congo red), and Cr(VI). Photocatalytic degradation experiments demonstrate exceptional efficiency in the removal of persistent organic pollutants. The photocatalytic results indicate that the prepared high-entropy (Ce0.2Pr0.2Zn0.2Nd0.2Tb0.2)2Zr2O7 zirconate pyrochlore oxide could effectively degrade dyes and reduce Cr(VI). Radical trapping experiments indicate that the degradation of dyes was driven by the hydroxyl radicals, superoxide radicals, and holes. Furthermore, the position of the valence band and conduction band promoted efficient photocatalytic reaction kinetics. The prepared photocatalyst remains structurally stable and can be reused three times without losing activity.

The lifespan of the transient electronic system can be determined in advance (i.e., predefined) or controlled via on-demand and programmable approaches using a diverse range of principles. However, in most cases, dissolution or disappearance requires an aqueous solution and is only possible for the entire system, not for specific or targeted components. Here, a soft, stretchable, thermally expandable system is introduced for precise, localized, on-demand deactivation or destruction of electronic systems. The incorporation of thermal expansion particles into a polymer matrix produces soft, resilient composites that generate substantial thermo-mechanical forces at a predefined temperature, enabling the direct collapse of electronic devices. Integration with multichannel microfluidics and wireless systems creates a vanishing, self-destructive optoelectronic system and bio-safe drug delivery vehicle for frequency-based selective release, demonstrating the broad potential of this approach in the fields of defense/security and biomedical devices as well as other envisioned areas.

Biocompatible and biodegradable polymer composite systems, featuring electrical and mechanical functionalities, have been studied as a means to enable biointegrated electronics, facilitating the acquisition of diverse valuable data. This involves establishing dependable connections with the pliable, irregular surfaces of human skin and organs to obtain a range of useful information. Previously, biodegradable conductive organic/inorganic materials such as conducting polymers and metal derivatives have been reviewed as a filler for polymer composites; however, there are no reviews about the utilization of conductive, semiconductive, and dielectric composites with various electrical/functional properties as electronic components for biomedical applications. These composites show considerable functions such as biodegradability, compatibility, electrochemical properties, magnetism, and photoluminescence. This review introduces the recent advances in biodegradable electronic devices using conductors, semiconductors, and dielectric-based composites besides their materials, and fabrication methods for monitoring physiological signals, therapeutic systems, energy storage, and drug delivery, as well as substrate and encapsulation materials.

Tungsten oxide (WO3) based metal oxide semiconductor material has been conventionally used for sensing inorganic gases at elevated temperatures. However, in this study, the gas sensing performance of tungsten oxide-based sensors is evaluated at room temperature. In this study, WO3 quantum dots (QDs) are synthesized via the electrochemical method, followed by a microwave treatment to dehydrate them. The newly developed process is relatively less expensive and offers the flexibility to alter the structure in terms of phase, size, shape, and vacancy concentration. It is observed that electrochemical process parameters play an important role in phase evolution and control the oxygen vacancy concentration in the powder, which are essential for enhancing its gas sensing characteristics. Results showed an enhanced gas-sensing ability of WO3 QDs at room temperature toward inorganic gases, such as CO, NO2, NH3, and H2 when subjected to microwave treatment. The enhanced gas-sensing performance of microwave-treated WO3 QDs is attributed to its smaller size and high oxygen vacancy concentration. The minimum limit of detection values for CO, NO2, NH3, and H2 at room temperature using microwave-treated hydrated tungsten oxide QDs were 4.60, 1.5, 0.35, and 10.25 ppm, respectively.

Navigation systems typically focus only on the distance from the user's origin to their destination and traffic optimization, which provides a solution for travelers to reach their destination, but adding more amenities to navigation systems can provide travelers with richer, actionable information that supports safer, healthier, and more comfortable journeys. In this regard, the current study provides a new context-aware navigation system by integrating the OpenStreetMap (OSM) application programming interfaces (APIs) with APIs of real-time environmental data such as air quality index (AQI), temperature, wind speed, rainfall forecasts, and cloudiness, as well as APIs of various important points of interest, including hotels, restaurants, cafes, fuel filling stations, bus stops, and railway stations. Incorporating these features into OSM provides travelers with key insights into the environmental conditions under which they choose to travel, visibility of other amenities close to their interests, which improves trip planning convenience, and it also provides information on other public transport modes for multimodal navigation before planning their itinerary. The current research work demonstrates the technical viability and real-world benefits of a unified navigation platform, which adjusts user needs and external factors via a multi-source, API-driven approach. In addition, this study underlines the significance of comprehensive, contextual mapping tools that enhance individualized travel experiences and promote human well-being.

Gas sensors have become vital components in recent years, with applications ranging from environmental monitoring to industrial safety and healthcare due to their ability to detect and quantify gases. This paper presents various types of gas sensors, including chemiresistive, non-dispersive infrared (NDIR), electrochemical, optical, thermal, catalytic, and surface acoustic wave-based sensors, highlighting their working principles, benefits, and limitations. A bibliometric analysis of research trends from 2013 to 2023 is conducted using data from the Scopus database, a leading source of peer-reviewed literature across scientific disciplines. The analysis explores trends in publications, author contributions, institutional affiliations, geographic distribution, subject areas, and funding sources. Additionally, recent advancements and challenges in gas sensor technologies are discussed, offering insights into innovations that may shape the future of gas sensing. This work serves as a valuable reference for researchers and industry professionals aiming to understand the current developments and future opportunities in gas sensor technology.

The rapid increase in industrialization and technological progress in recent years has led to the emission of various toxic and harmful gases, which contribute to the deterioration of air quality; Therefore, air quality monitoring has become of paramount importance. Among the various sensor technologies available, chemiresistive gas sensors (CGSs) have attracted considerable attention due to their simplicity in construction, cost-effectiveness, and ability to detect a wide range of gases. This review provides a comprehensive overview of the importance of CGSs in diverse applications, including environmental monitoring, industrial safety, and healthcare. The present review discusses bibliometric analysis highlighting publication trends, citation metrics, collaboration networks, and keyword usage, providing insights into the research field by analyzing Scopus data from 2013 to 2023. It also summarizes recent advances in CGS technology, including new sensor materials, fabrication techniques, and integration of CGS into smart devices. Despite significant progress, challenges such as excellent selectivity and sensitivity, and long-term stability still remain uncertain. We also discuss future research directions aimed at addressing these challenges, including development of novel materials, use of machine learning for improved selectivity, and miniaturization of sensors for various applications, including flexible and wearable applications.

The paper presents a Multiple-input- multiple-output (MIMO) antenna with four ports, designed on an 80 × 80 mm2 substrate. The antenna utilizes an Eighth-mode substrate integrated waveguide (EMSIW) circular cavity-backed structure, with narrow half-wavelength linear slots to suppress mutual coupling between the elements. This design provides a minimum isolation of 27 dB over the operational frequency band. The antennas are arranged at 90° angles to each other, are linearly polarized, and offer polarization diversity, further improving isolation. This orthogonal design creates overall system performance by lowering the potential of signal deterioration owing to multipath propagation. The Envelope Correlation Coefficient (ECC) is within the acceptable threshold across the operating band, confirming better diversity performance. The antenna operates at 3.5 GHz, with a gain of 1.39 dBi, making it suitable for 5G use cases, particularly in small-cell deployments for modern wireless communication systems where space and performance are major constraints.

Single sensors have been developed for specific gas detection in real-time environments, but their selectivity is limited by interference from other gases when considering mixtures of gases. Consequently, accurate detection of target gases in mixed gas environments is essential. Therefore, this study develops a sensor array approach to quantitatively estimate the concentration of carbon monoxide (CO) and nitrogen dioxide (NO2) gases in their binary mixture (CO and NO2). The sensor array consists of two different sensors, developed with zinc oxide and graphene-cobalt sulfide. The sensor array was tested in the presence of 29 different proportions of the binary mixture at room temperature. Subsequently, machine learning (ML) algorithms are applied on sensor signals to estimate the concentration of gases. The ML models unfortunately exhibited inaccurate prediction when all sensor signals were considered, therefore, to improve the prediction accuracy, the sensor signals were divided into three levels based on the mixed gas concentration regime. Interestingly, the classification and regression algorithms provided good classification accuracy (85.13 ± 3.2%) and reasonable predictions of target gas concentrations at three levels. The proposed computational framework can be extended to include additional gases in mixed gases and used in various applications, including automotive, industrial, and environmental monitoring. Graphical abstract: (Figure presented.)

Gas-sensing materials have seen significant development since the discovery of chemiresistive sensors, but the impact of electrode material and interdigitated electrode structure (IDEs) geometry on sensing performance has yet to be fully explored. To address, this study aims to investigate the effect of finger width (Wf) in IDEs on gas-sensing response. Tungsten oxide (WO3) is chosen as a sensing material to detect NO2 gas, synthesized using a simple hydrothermal method, and its material characteristics are corroborated using various analytical techniques. Next, three chemiresistive sensors with different Wf values of 50 µm (S1), 100 µm (S2), and 200 µm (S3) were fabricated. Gas-sensing properties show that S1 had a response 2.79 times higher than S2 and 3.28 times higher than S3. Accordingly, S1 is used to evaluate other sensing parameters. These parameters exhibit at least 1.61 times higher sensing response to NO2 than other gases, which might be attributed to the higher adsorption energy of NO2 on the WO3 surface. Furthermore, S1 provided a minimum detection limit of 450 ppb, quick response time and recovery time, and good repeatable response. These sensing properties ensure that the sensor has great potential for monitoring NO2 gas in various applications.

Unlike conventional rigid counterparts, soft and stretchable electronics forms crack- or defect-free conformal interfaces with biological tissues, enabling precise and reliable interventions in diagnosis and treatment of human diseases. Intrinsically soft and elastic materials, and device designs of innovative configurations and structures leads to the emergence of such features, particularly, the mechanical compliance provides seamless integration into continuous movements and deformations of dynamic organs such as the bladder and heart, without disrupting natural physiological functions. This review introduces the development of soft, implantable electronics tailored for dynamic organs, covering various materials, mechanical design strategies, and representative applications for the bladder and heart, and concludes with insights into future directions toward clinically relevant tools.

Wound healing is a complex and dynamic process, making the accurate and timely assessment of skin wounds a crucial aspect of effective wound care management, especially for chronic wounds. Unlike conventional wound dressings that simply cover the wound area once some form of medicine is administered onto the wound, recent studies have introduced versatile approaches to smart wound dressings capable of interacting with wound fluids to monitor physicochemical and pathological parameters to determine the wound healing status. Such electrochemical wound dressings can be integrated with on-demand, closed-loop drug delivery or stimulation systems and ultimately expanded into an ideal technological platform for the prevention, treatment, and management of skin wounds or illnesses. This article briefly reviews the wound healing mechanism and recent strategies for effective wound care management. Spe-cifically, this review discusses the following aspects of smart wound dressings: sensor-integrated smart bandages to detect wound bio-markers, smart bandages developed to accelerate wound healing, and wireless, closed-loop automatic (on-demand) wound healing systems. This review concludes by providing future perspectives on effective wound care management.

Improving the sensing performance of chemiresistive gas sensors is largely material-centric, but further studies are needed to optimize the performance of electrode interfaces and interdigitated electrode structures (IDEs) geometry. Hence, we systematically optimize IDEs geometry (spacing between fingers (Sf), finger width (Wf) and number of fingers (Nf)) using methane (100 ppm) selective nanomaterial. This study provides some fascinating findings: Changing the dimensions of Sf/Wf to 50–300 μm/20–75 μm in a constant device area increased sensing response by 1.2/1.54 times, possibly due to increased grain-to-grain contacts in sensing material/potential barrier between electrode and sensing material. Moreover, changing Nf from 2 to 44 and from 44 to 74 resulted in a 2.42-fold improvement and a 3.91-fold decrease in the sensing response, respectively. It can attribute to changes in the base charge density because it affects the contribution of charge carriers due to methane gas adsorption. This research opens the door for fabricating low-power highly sensitive gas sensors that can also be integrated into the Internet of Things.

Selective detection of hydrogen sulfide (H2S) gas is of great interest because of its direct impact on human health, the environment, and various industries including food, oil, construction, and medicine, which can also aid in early halitosis diagnosis. Therefore, this study presents a tin (II) sulfide (Sn S) based chemiresistive sensor for H2S gas detection, where Sn S is synthesized using a straightforward solvothermal technique, then verified using XRD and TEM analyses. The sensor is then fabricated with drop-coat technique and optimized to achieve maximum sensing performance by fine-tuning the operating temperature. The gas-sensing characteristics are then thoroughly measured at the optimized temperature of 100°C. Gas-sensing characteristics revealed that the sensor exhibits a wide dynamic range, an experimental detection limit of 0.875 ppm, good repeatability at 100 ppm and 50 ppm, and excellent selectivity to H2S gas over other gases. This performance can be attributed to higher surface-to-volume ratio of Sn S NPs, and Schottky contact at the interface between the gold electrode and Sn S NPs. Interestingly, while Sn S is known to be a p-type semiconductor, the gas-sensing results indicate an n-type semiconductor behavior, which can be explained by the Schottky contact at the interface between Au and Sn S. With its promising gas-sensing properties, the results of this study indicate that Sn S has the potential to detect various gases with high sensitivity and selectivity by exploring different nanostructures.

Chemiresistive gas sensors (CGS) are continuously being developed over other methods for detecting gas/vapor concentrations because of their simplicity of fabrication, compatibility with conventional DC circuits and high accuracy measurement convenience. However, humidity strongly influences sensing response, while the trade-off between humidity independence and gas response is one of the major barriers to limiting CGS for practical applications. In this regard, highly selective methane (CH4) gas sensor is fabricated using Gd0.2La0.2Ce0.2Hf0.2Zr0.2O2 (Ce-HEC) as a sensing material and the relative humidity (RH) effect on sensing response has been investigated. Indeed, the RH effect on the sensor response is high and can be seen in all gas concentrations at various RH levels. Therefore, humidity compensation model (HCM) is developed by fitting multivariate polynomial regression techniques to reduce the anti-interference humidity effect. HCM estimates the gas concentrations with a mean absolute percentage error of 5.81%, and a mean absolute error is 3.43 ppm. This study offers a simple and novel strategy for humidity-independent detection of gas/vapors in CGS and estimates gas concentrations with minimum error.

Surmounting the selectivity issue of gas sensors and detecting low ppm concentration of gases is highly significant for widespread deployments of sensors to build networks in applications including vehicular emission, fuel-based household appliances, and industrial emissions. Herein, a strategy is proposed to improve the selectivity and sensitivity of the cadmium sulfide (CdS) based sensor via changes in contact material by utilizing different metals. CdS was deposited via the SILAR method on three different glass substrates which have Au, ITO, and Ag contacts, respectively, through which Schottky barrier height (SBH) was adjusted between CdS and metal contact. CdS was thoroughly verified by structural and morphological characterization techniques. As-fabricated devices were tested, and gas sensing results suggest that Au and ITO contacts have significantly superior selectivity towards NO2 and CO gases over other gases. Further, experimental values reveal that sensors can detect up to 0.3 ppm and 1.25 ppm, respectively. Good selectivity can be attributed to the regulation of the SBH. Additionally, as-fabricated devices displayed good long-term stability and short response and recovery times. The present study may provide a rational design for fabricating a high-performance chemiresistive gas sensor for the detection of sub-ppm levels of hazardous gases present in the environment.

Detecting methane (CH4) with good selectivity is one of the most important safety precautions to prevent catastrophic incidents in the current industrial environment. Detection of small molecular size, inert and nonpolar characteristic gases at trace levels using chemiresistive technique at room temperature is still challenging because of weak adsorption between gas and sensing material. Therefore, we fabricated a single-phase high entropy oxide based chemiresistor and tested it towards the various gases and several hydrocarbons at room temperature, but the sensor displayed a higher selectivity to CH4 gas than other gases. Further, the sensor characteristics revealed a significant response to CH4 gas, good response and recovery time, good long-term stability, and an experimental detection limit of 25 ppm. Besides, the as-fabricated sensor is low-cost, small in size and consumes 50 nW power, much lower than the other commercialized light-based sensors. As proof of concept, the fabricated sensor was utilized to measure CH4 gas in a real-time atmosphere. The sensor reflected response characteristics similar to the controlled environment and recovered without carrier gas. This facile approach sheds light on the rational design of high-entropy oxides, paving the way for mass production and commercialization of ultra-trace gas detection sensors with superior sensing capability.

Monitoring wide-range carbon dioxide (CO2) levels with superior sensing performance is extremely important for environmental, human health, safety, and space applications. The reported chemiresistive sensors in the literature have critical drawbacks such as high-temperature operation and long response and recovery times (∼25 min), which remains a challenge for developing CO2sensors. Against these drawbacks, we report Gd0.2La0.2Y0.2Hf0.2Zr0.2O2(Y-HEC)-based sensors obtained by depositing Y-HEC on a glass substrate with different electrodes such as gold (Au), indium tin oxide (ITO), and silver (Ag) for CO2gas detection. The as-fabricated Y-HEC sensor with an ITO electrode displayed a maximum sensing response (46.7%) to 10000 ppm CO2gas at room temperature over other electrodes, which is attributed to the optimized Schottky barrier height between the ITO and Y-HEC. Furthermore, the experimental findings of the sensor with an ITO electrode revealed superior sensing characteristics such as wide-range CO2gas detection (250-10000 ppm), faster response and recovery times (49-200 s), high repeatability, strong selectivity to CO2over other gases, good long-term stability, and room temperature operation. Improvements in the CO2-sensing performance are attributed to nonagglomerated nanoparticles leading to the porous structure and high surface area, and intrinsic oxygen vacancies. We present an easy strategy to synthesize sensing materials and improve the desirable sensing performance for the development of practical applications of CO2sensors.

The metal-oxide semiconductor-based gas sensor has enthralled many researchers worldwide over past few decades. These sensors offer many advantages such as good selectivity, high sensitivity, and reliable and rapid detection of numerous pollutants. Among the pollutants, CO gas is highly toxic, and CO gas concentration of 9 ppm causes harmful effect on human health; thus, high sensitivity of CO gas detection is extremely significant. Herein, we present the room temperature detection of low concentration CO gas by utilizing cerium oxide microflowers anchored on graphene nanoplatelets (GNPs). The GNPs-CeO2 nanocomposite was synthesized using solvothermal method and followed by structural and morphological characterizations were performed using various analytical techniques. The chemiresistive gas sensor was fabricated with a nanocomposite solution drop-casted on cellulose paper as a substrate and silver paste as an electrode. The as-fabricated gas sensor explored for its applicability on CO gas detection with various concentrations and displayed good selectivity over NO2, SO2, NH3, and CO2. The gas sensing response of the device is due to large number of oxygen vacancies in the nanocomposite and the heterojunction between CeO2 and GNPs. The sensor offers a potential platform for metal oxide-based gas sensors operated at room-temperature and displayed good repeatability and stability.

Nitrogen dioxide (NO2) is one of the most harmful and highly toxic gas, and it is continuously released into the environment from automotive emissions, industrial emissions, and agriculture activities. According to the American Conference of Governmental Industrial Hygienists (ACGIH), the threshold limit value (TLV) of NO2 is up to 3 ppm for 8 h time-weighted average and 5 ppm for 15 min period. Therefore, the efficient detection of low concentration of NO2 gas is significant for monitoring human health in the near above-mentioned sources. In this aspect, transition metal dichalcogenides (TMDs) based gas sensor holds a promising potential for detecting the toxic gas due to their inherent properties such as, high surface to volume ratio and small intrinsic dimension. Among TMDs, tin disulfide (SnS2) has become a promising sensing material in gas sensing applications, owing to its physical affinity, planar crystal structure, and high specific surface area. Herein, SnS2 was synthesized by hydrothermal method and characterized by X-ray diffraction (XRD) and Raman spectroscopy. Subsequently, the chemiresistive gas sensor was fabricated by depositing SnS2 on the glass substrate which has gold (Au) interdigitated electrode pattern. The fabricated sensor was explored for detecting various gases such as CO, CO2, SO2, NH3, and NO2 at different temperatures (27°C, 60°C, 100°C, 150°C, 200°C, and 250°C) and a maximum response of 24.5% was obtained for 6 ppm NO2 gas at a temperature of 100°C, which demonstrates that the sensor is a highly selective among the other gases. Furthermore, the sensor was utilized to detect the range of NO2 concentrations from 1.5 ppm to 6 ppm at an optimum temperature of 100°C and the results revealed that the experimental detection limit is 1.5 ppm, and the response of the sensor was also observed to be a power law behavior. In addition, the plausible sensing mechanism was explored by use of surface charge transfer to NO2 gas and energy barrier modulation at the surface of SnS2.

This paper presents the power efficient and high speed novel flash analog to digital converter. The present research uses a dynamic double tail comparator and efficient low power encoding scheme intended of ultra high frequency range (GHz) for 5-bit flash analog to digital converter. The adapted comparator is having facilities of low voltages and high sampling rate frequencies. Output of comparator block i.e. thermometer code to binary conversion block is more important because it consumes more power and speed of the circuit rebates. An encoder block in this paper is converting the thermometer code into the intermediate gray code using the merged DCVSL technique and gray code to binary code using Ex-OR logic block. The conversion of thermometer code to gray code used to rebate the bubble errors in the flash ADC. To maintain the low power dissipation with high speed, the implementation of the encoder is Merged DCVSLPG logic is presented in this paper. The used comparator and encoder implemented on CADENCE tool in 65nm technology with 0.8 V power supply. The simulation results of flash analog to digital converter average power consumption and delay is 16.33 mw and 1.542 ps. The power delay product (PDP) or Figure of merit (FOM) of the flash ADC is 25.18 fJ.