Emerging Internet of Things driven carbon nanotubes-based devices

Carbon nanotubes (CNTs) have attracted great attentions in the field of electronics, sensors, healthcare, and energy conversion. Such emerging applications have driven the carbon nanotube research in a rapid fashion. Indeed, the structure control over CNTs has inspired an intensive research vortex due to the high promises in electronic and optical device applications. Here, this in-depth review is anticipated to provide insights into the controllable synthesis and applications of high-quality CNTs. First, the general synthesis and post-purification of CNTs are briefly discussed. Then, the state-of-the-art electronic device applications are discussed, including field-effect transistors, gas sensors, DNA biosensors, and pressure gauges. Besides, the optical sensors are delivered based on the photoluminescence. In addition, energy applications of CNTs are discussed such as thermoelectric energy generators. Eventually, future opportunities are proposed for the Internet of Things (IoT) oriented sensors, data processing, and artificial intelligence.

Enhancement Thermoelectric Properties of Cux-doped Nanostructure Bi-Sb-Te Thermoelectric Materials by Spark Plasma Sintering

Nanostructure Cux-doped Bi0.5Sb1.5-xTe3 thermoelectric materials was successfully prepared by Mechanical alloys and spark plasma sintering. In the reasearch, the crystallinity, particle size, and chemical composition were characterized by XRD, EDS, respectively. Thermoelectric properties with a maximum ZT value up to 1.17 has been obtained at 407 K in prepared Cu0.04-doped Bi0.5Sb1.496Te3 sample. The achieved higher ZT value is attributed that Cu as doping at the Sb sites introduced additional holes to enhance carrier mobility and Cu dopants interrupted the periodicity of lattice vibration to decrease lattice thermal conductivity. It is suggested that the as-prepared nanostructure Cux-doped Bi0.5Sb1.5-xTe3 thermoelectric materials has high potential for thermoelectric energy conversion application.

Intercalation Electrochemistry for Thermoelectric Energy Harvesting from Temperature Fluctuations

The effective use of energy from sustainable sources is considered a crucial step on the way to a CO2-neutral economy. Low-grade waste heat (< 100°C) is widely and ubiquitously available,...

Camphor sulfonic acid incorporation on SnO2/polyaniline nanocomposites for improved thermoelectric energy conversion

To modulate carrier transport and hence thermoelectric properties a facile approach has been undertaken by incorporation of tin dioxide (SnO2) in polyaniline (PANI) and subsequent treatment with camphor sulfonic acid...

Development of a Thermal Energy Harvesting Converter with Multiple Inputs and an Isolated Output

In this paper, an isolated multi-input single-output (MISO) converter is developed and applied to a thermoelectric energy conversion system to harvest thermal energy. The thermoelectric generators have individual maximum power point tracking functions. Furthermore, such a converter has a high step-up voltage conversion ratio. In addition, the presented converter is imposed on the thermoelectric energy conversion system with the three-point weighting strategy adopted to realize the maximum power point tracking (MPPT). In this paper, the basic principles of this converter are first described and analyzed, and finally some simulated and experimental results are offered to verify the feasibility and effectiveness of such a thermal energy harvesting system.

Tuning the Anisotropic Thermal Transport in {110}-Silicon Membranes with Surface Resonances

Understanding the thermal transport in nanostructures has important applications in fields such as thermoelectric energy conversion, novel computing and heat dissipation. Using non-homogeneous equilibrium molecular dynamic simulations, we studied the thermal transport in pristine and resonant Si membranes bounded with {110} facets. The break of symmetry by surfaces led to the anisotropic thermal transport with the thermal conductivity along the [110]-direction to be 1.78 times larger than that along the [100]-direction in the pristine structure. In the pristine membranes, the mean free path of phonons along both the [100]- and [110]-directions could reach up to ∼100 µm. Such modes with ultra-long MFP could be effectively hindered by surface resonant pillars. As a result, the thermal conductivity was significantly reduced in resonant structures, with 87.0% and 80.8% reductions along the [110]- and [100]-directions, respectively. The thermal transport anisotropy was also reduced, with the ratio κ110/κ100 decreasing to 1.23. For both the pristine and resonant membranes, the thermal transport was mainly conducted by the in-plane modes. The current work could provide further insights in understanding the thermal transport in thin membranes and resonant structures.

Research on the performance of two different porphin graphene nanoribbons coupled thermoelectric devices

The effect of bonding position on the energy conversion efficiency of porphin graphene nanoribbons coupled thermoelectric devices was studied by the first-principles. The results show that the change of bonding position can greatly adjust the lattice thermal conductivity of the coupled thermoelectric devices; although the change of bonding position has no obvious effect on the transport properties of holes in the coupled structure, it can obviously adjust the transport properties of electrons, resulting in the different Seebeck coefficients and quality merit values of different coupled thermoelectric devices The results illustrate the different thermoelectric energy conversion effects in different porphin graphene nanoribbons coupled thermoelectric devices with different bonding positions, which provides an effective theoretical basis for the design of thermoelectric quantum devices based on graphene nanoribbons.

Environment-Monitoring IoT Devices Powered by a TEG Which Converts Thermal Flux between Air and Near-Surface Soil into Electrical Energy

Energy harvesting has an essential role in the development of reliable devices for environmental wireless sensor networks (EWSN) in the Internet of Things (IoT), without considering the need to replace discharged batteries. Thermoelectric energy is a renewable energy source that can be exploited in order to efficiently charge a battery. The paper presents a simulation of an environment monitoring device powered by a thermoelectric generator (TEG) that harvests energy from the temperature difference between air and soil. The simulation represents a mathematical description of an EWSN, which consists of a sensor model powered by a DC/DC boost converter via a TEG and a load, which simulates data transmission, a control algorithm and data collection. The results section provides a detailed description of the harvested energy parameters and properties and their possibilities for use. The harvested energy allows supplying the load with an average power of 129.04 μW and maximum power of 752.27 μW. The first part of the results section examines the process of temperature differences and the daily amount of harvested energy. The second part of the results section provides a comprehensive analysis of various settings for the EWSN device’s operational period and sleep consumption. The study investigates the device’s number of operational cycles, quantity of energy used, discharge time, failures and overheads.