• Energy Research

Abstract The long mean free path close to a micrometer in encapsulated graphene enabled us to rectify currents ballistically at room temperature. In this study, we introduce a ballistic rectifier that resembles a diode bridge and is based on graphene encapsulated using hexagonal boron nitride. Our device’s asymmetric geometry combined with the exploitation of the ratcheting effect means that it can operate successfully and provides excellent performance. The device’s estimated responsivities at 38,000 V/W for holes and 23,000 V/W for electrons at room temperature, are among the highest values for a ballistic device reported to date. Due to the device’s zero threshold voltage, it is able to rectify Johnson noise signals converting thermal excitation to electrical energy at room temperature. The bandwidth of the device at the ballistic regime is estimated at ~ 1.1 GHz for holes and 2 GHz for electrons. The device developed in this study is an important step along an innovative pathway that will lead to harvesting electrical energy directly from thermal energy.

Oceanenergy is one of these renewable sources comprising a vast amount of the renewable energy source as it covers 70% of the earth. This paper focuses on the idea of getting benefitted by one of the largest sources of renewable energy source by absorbing its energy in the form of marine and tidal current energy, thermal energy, wave energy etc. This paper will also give us a perspective of how harvesting of the ocean energy would change the traditional energy production business with respect to economy, efficiency and its effect on nature

Semiconductor nanorods and nanowires are interesting nanomaterials and have been applied in sensor and energy applications. Tellurium is a typical p-type semiconductor having bandgap energy of 0.35 eV and has already been recognized as an interesting material for fabricating nanodevices. For examples, tellurium nanowires have shown great potential in the applications of nanogenerators, supercapacitor, lithium battery, and biosensors. In this paper, we developed a thin, light-weight, and flexible thermoelectric nanogenerator based on the nanocomposite of tellurium nanowire arrays and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The Seebeck coefficient of the nanocomposite was determined to be 235 μV/K. A linear relationship between the output voltage and the temperature difference across the thermoelectric nanogenerator was observed. We demonstrated that the thermoelectric nanogenerator can be integrated with fiber fabric and harvested the thermal energy from human body temperature. Not only for the purpose of energy harvesting, the thermoelectric nanogenerator can also function as a self-powered sensor for water temperature measurement.

This dataset holds all measurements recorded by a custom-built thermal harvesting tracking collar - including GPS-position, four temperature readings, acceleration, timestamps. Three collars, two of them supplied solely by thermal energy harvesting, were attached to cashmere-goats from 26 May to 12 July 2020.

Thermoelectric generators (TEGs) operate in the presence of a temperature gradient, where the constituent thermoelectric (TE) material converts heat into electricity via the Seebeck effect. However, TE materials are characterised by a thermoelectric figure of merit (ZT) and/or power factor (PF), which often has a strong dependence on temperature. Thus, a single TE material spanning a given temperature range is unlikely to have an optimal ZT or PF across the entire range, leading to inefficient TEG performance. Here, we demonstrate compositionally graded organic-inorganic nanocomposites, where the composition of the TE nanocomposite is systematically tuned along the length of the TEG, in order to optimise the PF along the applied temperature gradient. The nanocomposite composition can be dynamically tuned by an aerosol-jet printing method with controlled in-situ mixing capability, thus enabling the realisation of such compositionally graded thermoelectric composites (CG-TECs). We show how CG-TECs can be realised by varying the loading weight percentage of Bi2Te3 nanoparticles or Sb2Te3 nanoflakes within an organic conducting matrix using bespoke solution-processable inks. The enhanced energy harvesting capability of these CG-TECs from low-grade waste heat (<100 °C) is demonstrated, highlighting the improvement in output power over single-component TEGs.