Phys.org November 6, 2022 An international team of researchers (France, Japan, Germany) synthesized a series of self-doped compounds Cu2+xMn1−xGeS4 through Cu for Mn substitution. Using a combination of powder X-ray diffraction, high resolution transmission electron microscopy and precession-assisted electron diffraction tomography, they showed that the materials were composed of interconnected enargite- and stannite-type structures, via the formation of nanodomains with a high density of coherent interfaces. By combining experiments with ab initio electron and phonon calculations, they discussed the structure–thermoelectric properties relationships and clarified the interesting crystal chemistry in this system. They demonstrated that excess Cu+ substituted for Mn2+ dopes […]
Tag Archives: Power generation
A new heat engine with no moving parts is as efficient as a steam turbine
MIT News April 13. 2022 Thermophotovoltaics (TPVs) can enable approaches to energy storage and conversion that use higher temperature heat sources than the turbines. However, despite predictions that TPV efficiencies can exceed 50% the demonstrated efficiencies are still only as high as 32%. A team of researchers in the US (MIT, National Renewable Energy Laboratory) has fabricated TPV cells with efficiencies of more than 40% and experimentally demonstrated the efficiency of high-bandgap tandem TPV cells. The TPV cells comprising III–V materials with bandgaps between 1.0 and 1.4 eV are optimized for emitter temperatures of 1,900–2,400 °C. The cells exploit the concept […]
A new ‘gold standard’ compound for generating electricity from heat
Phys.org May 26, 2021 The principal challenges in current thermoelectric power generation modules are the availability of stable, diffusion-resistant, lossless electrical and thermal metal–semiconductor contacts that do not degrade at the hot end nor cause reductions in device efficiency. Transverse thermoelectrics avoid this problem by producing a current that runs perpendicular to the conducting device, requiring contacts only on the cold end of the generator. However, the materials known to create this sideways voltage are impractically inefficient. A team of researchers in the US (Ohio State University, University of Illinois) demonstrated that a layered crystal consisting of the elements rhenium […]
An optical coating like no other
Nanowerk February 5, 2021 An international team of researchers (USA – University of Rochester, Case western University, Italy) applied a 15 nanometer-thick film of germanium to a metal surface resulting in a surface capable absorbing a broad band of wavelengths. Combining it with a cavity that supports a narrowband resonance resulted in coupled cavities that exhibit Fano resonance that can reflect a very narrow band of light. The semi-transparent Fano resonance optical coationgs (FROCs) can transmit and reflect the same colour as a beam splitter filter. FROCs can spectrally and spatially separate the thermal and photovoltaic bands of the solar spectrum, […]
Development of highly sensitive diode, converts microwaves to electricity
Science Daily September 26, 2019 Researchers in Japan have developed a highly sensitive rectifying element in the form of a nanowire backward diode, which can covert low-power microwaves into electricity. Equipment they used consists of a radio wave power generating element. The technology can efficiently convert 100nW-class low-power radio waves into electricity, enabling the conversion of microwaves emitted into the environment from mobile phone base stations in an area that is over 10 times greater than was previously possible. The researchers expect that the nanowire backward diode will be applied in using plentiful ambient radio wave energy in 5G communications, […]
Underwater power generation
Science Daily May 13, 2019 Inspired by marine organisms that have switchable energy extraction modes (aerobic respiration for long‐term living or anaerobic respiration to propose instantaneously high output power for fast movement),researchers in China have designed an auto‐switchable dual‐mode seawater energy extraction system to provide high energy density and power density both by initiatively choosing different solutes in seawater as electron acceptors. The key to the discovery is a cathode made of Prussian blue, an open framework structure with cyanide ions as “struts” and iron ions as “nodes,” which can easily accept and release electrons. When combined with a metal […]
Using spin current to convert mechanical vibrations into electricity
Nanowerk July 20, 2018 Researchers in Japan have designed a nanoscale device that converts mechanical ripples into an electrical current via a spin current. They found that the spin current generated in the second layer was large enough to move magnetic domain walls, which could be used in memory devices. It is still below the spin currents needed, but they could be increased by optimizing the devices. The technology could be used in devices that permit sound waves to pass in one direction but block them in the opposite direction… read more. TECHNICAL ARTICLE