Smart Energy-Harvesting Coating for Moisture-Droplets Based on Ionic Diodes and Transistor-Like Structures.

Porous Si/C/reduced graphene oxide microspheres by spray drying as anode for Li-ion batteries

Asymmetric membranes derived from the stacking of graphene oxide (GO) nanosheets have attracted great attention for the fabrication of ionic diodes. Herein, we described an ionic diode based on a polypyrrole-modified GO membrane with a vertical asymmetry, which was achieved by a spontaneous oxidation polymerization of pyrrole monomers on one side of the GO membrane in vapor phase. This asymmetric modification resulted in an asymmetric geometry due to the occupation of the interlayer space of one side of the GO membrane by polypyrrole. Our ionic diode demonstrated an obvious ionic rectification behavior over a wide voltage range. A calculation based on Poisson–Nernst–Planck equations was used to theoretically investigate the role of asymmetric modification of polypyrrole.

Energy harvesting from ubiquitous natural water vapor based on moisture electric generator (MEG) technology holds great potential to power portable electronics, the Internet of Things, and wireless transmission. However, most devices still encounter challenges of low output, and a single MEG complemented with another form of energy harvesting for achieving high power has seldom been demonstrated. Herein, we report a flexible and efficient hybrid generator capable of harvesting moisture and tribo energies simultaneously, both from the source of water droplets. The moisture electric and triboelectric layers are based on a water-absorbent citric acid (CA)-mediated polyglutamic acid (PGA) hydrogel and porous electret expanded polytetrafluoroethylene (E-PTFE), respectively. Such a waterproof E-PTFE film not only enables efficient triboelectrification with water droplets' contact but also facilitates water vapor to be transferred into the hydrogel layer for moisture electricity generation. A single hybrid generator under water droplets' impact delivers a DC voltage of 0.55 V and a peak current density of 120 μA cm-2 from the MEG, together with a simultaneous AC output voltage of 300 V and a current of 400 μA from the complementary water-based triboelectric generator (TEG) side. Such a hybrid generator can work even under harsh wild environments with 5 °C cold and saltwater impacts. Significantly, an optical alarm and wireless communication system for wild, complex, and emergency scenarios is demonstrated with power from the hybrid generators. This work expands the applications of water-based electricity generation technologies and provides insight into harvesting multiple potential energies in the natural environment with high output.

Internet of Things (IoT) applications can offer a great potential of benefits to end users. We are moving towards an Internet of People, Things and Services (IoPTS) and a future world of ambient intelligence, where users can seamlessly interact with IoT devices and get information about the services they offer. Interaction can take place directly or through dedicated mobile apps that are built to acquire data from sensors or clusters of IoT devices. The article presents a user-centric cluster framework, taking into account the resource-constrained nature of the IoT devices. As part of the framework, the authors propose a Mobility Aware Clustering Scheme (MACS), which organizes the IoT devices in clusters using a fitness function for each node, and a Profile Aware Proactive Cluster Discovery (PAPCD) mechanism using Bluetooth Low Energy (BLE) beacons for service advertisement. The authors also propose an IoT service filtering and ranking algorithm to match the users' preferences and requirements

Continuous photocatalytic removal of chromium (VI) with structurally stable and porous Ag/Ag3PO4/reduced graphene oxide microspheres

Graphene oxide (GO) was used as a solid surfactant, and core–shell structured polystyrene (PS)–GO microspheres were fabricated using the Pickering emulsion polymerization method. The resulting electro-responsive ‘smart’ microspheres were dispersed in silicone oil and their electrorheological characteristics were measured using a rotational rheometer under an applied electric field and correlated with their dielectric properties. The GO was found to impart electro-responsive properties to the polymer composite suspension under an applied electric field.

This study investigates hybrid energy harvesting(EH) as a sustainable and efficient power solution for Internet of Things (IoT) devices. Traditional battery-powered and single-source energy systems have limitations, such as limited lifetime and unreliable power availability. To address these issues, a hybrid energy harvesting system is proposed that combines photovoltaic energy (solar), radio frequency energy(RF) , and vibration energy sources. These sources capture energy from the surrounding environment, allowing the system to operate under different conditions. By using multiple energy sources together, the proposed model provides more reliable and continuously power in both urban and remote environments. The system performance is evaluated using simulated environmental data for different deployment scenarios. The results shows that the harvested energy is sufficient to support low-power IoT devices. Unlike, conventional systems, the proposed approach reduces the need for frequent battery replacement, which increases device lifespan and lowers maintenance requirements. The study demonstrates that hybrid energy harvesting is a practical and effective solution for autonomous Internet of things (IoT) applications. This work supports the development of self-powered, scalable, and environmentally friendly IoT networks, especially in locations that are difficult to access. Keywords Wireless Energy Harvesting(WSN), Internet of Things(IoT), Hybrid Energy Harvesting, Solar Energy, Vibration, Radio Frequency Energy, Self-Powered Iot, Energy Management.

Internet of Things (IoT) has become one of the trending technologies in recent years. With the wide applications and rapid development of wireless communication and IoT, there are growing number of requirements on novel device design, such as flexible antennas and tunable antennas. The demand of transparent and flexible wireless communicational devices is ever-increasing for a wide range of scenarios, such as noninvasive healthcare, real-time wearable electronics, etc. Besides, a highly integrated antenna with tunable bandwidth and low energy consumption is in pressing demands in order to reduce the number of antennas and achieve better signal strength and higher speed signal transmission. Graphene materials have drawn much attention due to its extraordinary optical properties, high electrical and thermal conductivity, and excellent mechanical properties. All of these properties underline that graphene can be considered as a highly competitive material for wearable communication devices. Moreover, the electrical resistance of graphene and graphene oxide could be simply changed by external electric fields, applied strain and environment, which alters the electrical characteristics of the graphene-based microwave devices. Accordingly, graphene materials have a great potential in various reconfigurable or tunable devices. Our group fabricated the first graphene-based flexible and transparent wireless antenna with 2D large single-crystalline graphene and 1D AgNW hybrid material based on the features of graphene, such as high carrier mobility, transparency and flexibility, etc. The antenna exhibited a 75% light transmittance and an ultrawide bandwidth ranging from 5.6 to 12.8 GHz, combining with outstanding durability and stability with an almost negligible variation of reflection coefficients over 1000 bending cycles. Further research confirmed that the existence of graphene harmonized the compatibility between antenna and integrated chips, hence improved the total performance of the radio frequency identification (RFID) tags. Graphene/AgNW-based RFID tag was fabricated with an operating UHF band of 850–960 MHz and a reading distance of 130 cm, showing a great commercial potential. The excellent performance and unique properties of graphene/AgNW-based antenna and RFID tag came from the synergistic effect between 1D and 2D nanomaterials, providing a new vision for the design of next generation wireless electronics. Meanwhile, a slot antenna with tunable bandwidth was proposed. The antenna consisted of a planar slot antenna with graphene ink printed at the gap between the ground and a small patch. The graphene ink was made from the mixture of graphene powder and graphene oxide aqueous dispersion. Graphene oxide sheets functioned as effective surfactants rendering assistance to form uniform printable inks, displayed alterable electrical resistance by optimization of mixing proportions between graphene and graphene oxide. Dried graphene inks displayed tunable electrical resistance under applied DC voltages. The variation in the resistance of graphene ink affected radiation of the slot antenna, resulting in a shift of operating bandwidth. The proposed antenna achieved a shifting bandwidth of 0.54 from 6 to 5.46 GHz after applying DC voltage less than 15 V. Such cost-effective, easily acquired, and printable graphene inks integrated the dual advantages of graphene and graphene oxide. It could be further applied in many other fields of printable electronic devices.

This review paper explores the pivotal role of telecommunications in enabling Internet of Things (IoT) connectivity and applications, providing a comprehensive overview of the current landscape and future prospects. The primary objective is to synthesize existing research and industry insights to highlight how advancements in telecommunications infrastructure and technology have catalyzed the adoption and expansion of IoT. The review systematically examines the evolution of telecommunications technologies, including 4G, 5G, and emerging network protocols such as Narrowband IoT (NB-IoT) and Long-Term Evolution for Machines (LTE-M). It assesses how these technologies enhance IoT connectivity by providing the necessary bandwidth, low latency, and reliability for real-time data exchange and device interoperability. Key findings from the literature reveal that the deployment of 5G networks has been a game-changer for IoT, offering unprecedented speeds and connectivity capabilities that support a wide range of applications in smart cities, healthcare, agriculture, and industrial automation. Additionally, the paper discusses the role of telecommunications in addressing challenges related to security, scalability, and energy efficiency in IoT deployments. The review concludes that telecommunications are integral to the growth and sustainability of IoT ecosystems. As telecommunications technology continues to advance, its ability to support increasingly complex and ubiquitous IoT applications will drive innovation and enhance efficiency across various sectors. The paper emphasizes the necessity for ongoing investment in telecommunications infrastructure and research to fully exploit the transformative potential of IoT connectivity and applications.

The concept of the Internet of Industrial Things (IIoT), which emerged when the Internet of Things (IoT) applications started to be used in the industry, has provided the efficiency, flexibility, traceability and security to the end users in their workspaces. Indoor monitoring and control systems, which are the leading applications of the Internet of industrial things, play a major role in providing these elements. Over the years, these systems have evolved from wired alarm systems to data loggers, wireless sensor networks, and then to with cloud computing based smart gateways. In the face of this evolution of systems, the expectations of end users such as being able to control at tens of thousands of points, high quality of service or achieving commercial targets have increased at the same rate. In order to meet all these expectations, a modular and compact platform based on Fog Computing and single board computer, which provides optimum performance and cost, has been designed and developed in this study. When the results obtained from the test processes implemented under real scenarios are examined, it is seen that the hardware used and the software infrastructure, all open source, are sufficient and usable for indoor monitoring and control applications.

As the world seeks sustainable energy solutions, Internet of Things (IoT) applications demand consistent and efficient power sources. This paper presents an innovative hybrid renewable energy system, seamlessly integrating solar photovoltaic panels, wind turbines, and hydrogen fuel cells, tailored for IoT applications. Through machine learning algorithms, our proposed system not only optimizes energy generation in real-time but also ensures uninterrupted energy supply to IoT devices and consumers, even in fluctuating environmental conditions. This universal approach markedly diminishes the dependence on non-renewable energy sources, promoting a greener and more resilient energy infrastructure. The incorporation of hydrogen fuel cells uniquely positions our system as a reservoir for excess energy, ensuring consistent power even when solar or wind outputs diminish. Moreover, by synchronizing IoT devices with our energy system, we have procured real-time data on energy dynamics, facilitating unparalleled optimization and reduced wastage. The presented system shows the way for a sustainable future through the efficient green energy generation with the ever-evolving landscape of IoT applications and machine learning techniques.

The concept of Internet-of-Things (IoT) emerged around two decades ago but has gained momentum during the last few years. The modern technology has infused this innovative paradigm on several scales but still lacks shadowing many aspects of our daily life. Several businesses have attempted its interjection in their processes, however, some of the features of IoT have been avoided by most of them due to its cryptic nature and requiring technical skills prior to its replete use. The development of IoT is well ahead of its need to be and linked to an inability of adopting its fast-paced changes along with the lack of strong business operational models. This paper contributes to the developing of a smart home where electrical appliances would react according to the environment while users would be able to control them through smart gadgets. The conventional setup of arranging and organising the electrical appliances is compared to the newly-developed, several patterns have been observed through which carbon footprints and electricity consumption could be reduced. The collected data has been analysed and it proves that IoT does not only helps save energy consumption but also to save the environment. This paper also highlights the challenges faced by consumers who are affected by the penetration of IoT into their lives along with benefits of infusing IoT applications. The overall theme of this paper is, therefore, to make the consumer understand the benefits of IoT applications into their lives using Arduino setup to control electrical home appliances as a benchmark.

A microfiber interferometer based on a single-mode tapered-no-core single-mode (STNCS) fiber structure coated with a thin layer of graphene oxide (GO) was proposed and demonstrated as a relative humidity (RH) sensor. The STNCS fiber structure has a strong evanescent field, which can sensitively response to changes in the surrounding refractive index. The moisture-sensitive material GO was used to form the film on the no-core fiber by a dip impregnation method. The effects of GO concentration and the tapered waist diameter on RH sensitivity were studied experimentally. The experimental results showed that a thinner waist diameter provides higher RH sensitivity. When the concentration of GO solution is 0.01 mg/mL, the STNCS fiber structure with a waist diameter of 2.9 μm performs better in RH sensing; a high sensitivity of 0.461 nm/%RH in the range of 40-98% was achieved. The sensor has good stability with wavelength fluctuations of ±0.009 nm and ±0.008 nm over 60 mins at RHs of 50% and 80%, respectively. The proposed fiber optic humidity sensor has a high sensitivity over a wide measurement range and offers good stability showing promising potential application in the field of RH sensing.

Small wearables to large industrial systems—the Internet of Things (IoT) is radically altering modern living. Infrastructure and amenities that are ubiquitous, dependable, high performing, efficient, and scalable are needed for the Internet of Things. IoT services work with a wide range of devices, from simple to complicated technologies, and communication occurs through a variety of networks. Cloud computing is the most significant aspect of the Internet of Things since it not only connects servers, but it also analyzes critical data acquired from sensors while also providing sufficient storage space. Further organisation and resale data will be required in the near future to finish this attribution. Certain Internet of Things (IoT) applications facilitate process automation and allow non-living physical things to function without the need for human interaction. Internet of Things (IoT) applications in the industrial sector could boost productivity and enable more extensive networks of communication between workers and equipment. Ultimately, this would enable a greater number of competitive businesses to enter the market, which would improve quality control and reduce losses. This article discusses many technologies risks as well as their advantages and the many uses of IoT, including smart towns and cities, medical care, and industry.

Graphene oxide (GO) exhibits relatively high proton conduction even at low relative humidity (RH) and temperatures. Thus, multi-layered GO film (GO paper) is a promising electrolyte in various cells and batteries. We report the in-plane and through-plane proton conductivities of GO paper at low RH and room temperature. The conductivities were 10−5-10−4 S/cm at RH of 10–20%. We examined the performance of a graphene oxide fuel cell (GOFC) with GO paper as the electrolyte at low RH (<20%) and room temperature. We demonstrated that a simple membrane electrode assembly (MEA) based on Pt/GO/Pt system functioned as a H2/O2 fuel cell. The GOFC with Pt/C electrodes afforded better fuel cell performance than a MEA composed of Pt/C electrodes and Nafion electrolyte. GO paper composed of nano-sized GO (nanoGO) flakes enhanced the performance of the GOFC, particularly the current density. Furthermore, a composite of Fe phthalocyanine (PcFe) /reduced GO (rGO)/TiO2 could act as the Pt-free oxygen electrode in GOFC, although the fuel cell performance should be improved for practical applications. Our study suggests that a low cost GOFC without a Nafion electrolyte and noble metal electrodes could be fabricated in the near future.