Knezevic department of electrical and computer engineering, university of wisconsinmadison, madison, wisconsin 53706, usa. Numerical study of the thermoelectric power factor in ultra. The electrical components such as meandershaped micro heaters h l, h r, resistance thermometers in fourpoint arrangement t l, t. Thermoelectric silicon material reaches recordlow thermal. Pdf thermoelectric materials interconvert thermal gradients and electric fields for power generation or for refrigeration. Scientists from the university of warwick, in collaboration with the universities of cambridge and birmingham, have demonstrated how thermoelectric materials which harvest waste heat and convert it into electricity could be an important source of renewable. Researchers at sandia national laboratories say better materials and manufacturing techniques for the nanowires could allow carmakers to harvest power from the heat wasted by exhaust systems or lead to more efficient devices to cool computer chips. Nanowire silicon as a material for thermoelectric energy.
Determining factors of thermoelectric properties of. Selective growth of ge nanowires by lowtemperature. Approximately 90 per cent of the worlds power is generated by heat engines that use fossil fuel combustion as a heat source and typically operate at 3040 percent efficiency, such that roughly 15 terawatts of heat is lost to the environment hochbaum et al. After identifying the most stable structures for gaas nws, either in wurtzite wz or zinc blende zb stacking, we present a systematic analysis on t.
According to solid state physics, semiconductor, semimetal, and some alloys are ideal thermoelectric material, and the efficiency of the thermoelectric materials depends on the thermoelectric figure of merit zt ztts 2. Design principle of telluridebased nanowire heterostructures for potential thermoelectric applications genqiang zhang. Silicon could be a good thermoelectric material offering cmos compatibility. Hoffman1,2, daniele ercolani3, francesco rossella3, alessandro pitanti3, alessandro cavalli1, stefano roddaro3, gerhard abstreiter1,2, lucia sorba3, and ilaria zardo1,4 nano res. Nanowires can make highly effective thermoelectric materials.
Optimizing thermoelectric efficiency of superlattice. Extensive studies have shown that in bulk thermoelectric materials, it is difficult to achieve a figure of merit zt larger than one at room temperature 1,2. The potential of using silicon as thermoelectric materials are introduced. L the electronic and lattice thermal conductivities, respectively. Alternatively, nanowires can be defined as structures that have a thickness or diameter constrained to tens of nanometers or less and an unconstrained length. Silicon nanowire arrays as thermoelectric material for a. This volume focuses on various aspects of nanowires for energy applications, presenting interesting sections on electrospun semiconductor metal oxide nanowires for energy and sensing applications, integration into. Researchers at sandia national laboratories say better materials and manufacturing techniques for the nanowires could allow.
A nanowire is a nanostructure, with the diameter of the order of a nanometer 10. Rational synthesis of ultrathin ntype bi te nanowires with. Oct 05, 2016 thermoelectric silicon material reaches recordlow thermal conductivity. Bi2te3 nanowire arrayepoxy composites for thermoelectric. Boukai ai, bunimovich y, tahirkheli j, yu jk, goddard wa iii, heath jr. Thermoelectric materials harvest waste heat and convert it into electricity and are much soughtafter as renewable and environmentally friendly sources of energy. Yet poor heat transport is advantageous for thermoelectric materials, which are characterized by a figure of merit zt. Thermoelectric modules could potentially convert part of this lowgrade waste heat to electricity lecher, 1905. Silver chalcogenides have received much attention in potential thermoelectric materials research because of high carrier mobility and low effective mass. Thermoelectric materials interconvert thermal gradients and electric fields for power generation or for refrigeration1,2. Zt3 or higher is required to use thermoelectric devices as an efficient alternative to mechanical heat engines.
Thermoelectric power measurement of catalystfree sidoped. Here we report efficient thermoelectric performance from the singlecomponent system of silicon nanowires for crosssectional areas of 10 nm 20 nm and 20 nm 20 nm. Thermoelectric properties of a single crystalline ag2te. Thermoelectric te materials convert heat to electricity and can improve energy efficiency by harvesting waste heat for power generation or improve refrigeration. The efficiency of thermoelectric te materials is quantified by the figure of merit z t s 2. Scientists from the university of warwick, in collaboration with the universities of cambridge and birmingham, have demonstrated how thermoelectric materials which harvest waste heat and convert it into electricity could be. All nanowire series products offer a multitude of possibilities for research and development, as well as both practical and novel usage in modern production and manufacturing. Nanowires for energy applications, volume 98, covers the latest breakthrough research and exciting developments in nanowires for energy applications. Nanowire series products supplier acs material, llc. This work provides detailed insight into charge and heat transport in disordered yet nanocrystalline materials and advances their engineering for thermoelectric.
Jan 10, 2008 thermoelectric materials, capable of converting a thermal gradient to an electric field and vice versa, could be useful in power generation and refrigeration. Numerical study of the thermoelectric power factor in. Silicon nanowires promising material for photovoltaic. Rational synthesis of ultrathin ntype bi te nanowires. Complete thermoelectric benchmarking of individual insb nanowires by combined microraman and electric transport analysis sara yazji1,2, eric a. Silicide nanowires and nanoparticles for thermoelectrics. Among the nanoscale semiconductor materials, silicongermaniumsige alloy nanowire is a promising candidate for thermoelectric materials the. Optimal thermoelectric figure of merit of sige coreshell. Using vapor liquid solid grown silicon nanowires, it was established early in this lab that their thermal conductivity can be signi. Bulk silicon is a poor thermoelectric material at room temperature, but by substantially reducing the thermal conductivity of our silicon nanowires without significantly reducing electrical conductivity, we have obtained zt values of 0.
The thermoelectric efficiency is related to the thermoelectric figure of merit, which depends on different parameters of the material. Volume 1439 symposium naa nanowires and nanotubessynthesis, properties, devices, and energy applications of onedimensional materials 2012, pp. Bi 2 te 3, nanowires, thermoelectric, spark plasma sintering t hermoelectric materials, which can generate electricity by recovering waste heat or be used as solidstate cooling. Combining density functional theory and the nonequilibrium greens function method, we investigate the thermoelectric properties of thin gaas nanowires nws.
Semiconductor nanowires promise to provide the building blocks for a new generation of nanoscale electronic and optoelectronic devices. Nanowires made of thermoelectric materials and devices that comprise arrays of such nanowires can be fabricated by electrochemical growth of the thermoelectric materials in templates that contain suitably dimensioned pores 10 to 100 nm in diameter and 1 to 100. The lead salts are chosen for our studies of superlattice nanowires because they are conventionally good thermoelectric materials. Materials, synthesis, characterization and applications covers advanced materials for nanowires, the growth and synthesis of semiconductor nanowiresincluding methods such as solution growth, movpe. The drawback of the teg is its relatively low efficiency due to the limited performance of te materials and high material costs. Templated nanowire arrays14 of thermoelectric materials have attracted attention over the last decade due to their potential application in the low cost, high yield fabrication of thermoelectric elements with lengths in the range of tens to. Nanoscale semiconduction silicides as efficient thermoelectric materials thermoelectric te materials convert heat to electricity and can improve energy efficiency by harvesting waste heat for power generation or improve refrigeration. Thermoelectric silicon material reaches recordlow thermal conductivity. Dec 17, 2011 in order to use silicon as an efficient thermoelectric te material for te energy conversion, it is necessary to reduce its relatively high thermal conductivity, while maintaining the high power factor.
Thermoelectric properties of ultrathin silicon nanowires. Evolution of thermoelectric figure of merit from 3d bulk to 1d snte behind and a collection of synthesised nanowires below. The elemental composition of assynthesized ag 2 te nanowires was examined by energy dispersive xray spectrometry eds using tem. Heath, silicon nanowires as efficient thermoelectric materials. Enhanced thermoelectric figure of merit in thin gaas. Thermoelectric efficiency in model nanowires sabuhi badalov m. In order to use silicon as an efficient thermoelectric te material for te energy conversion, it is necessary to reduce its relatively high thermal conductivity, while maintaining the high power factor. Silicon nanowires show great potential as thermoelectric materials, but prepara.
Nanowires display enhanced thermoelectric potential the engineer. With the advances of nanostructure technology, many experiments nowadays can realize zt larger than one at room temperature in lowdimensional structures 3,4. Bi 2 te 3 nanowires are promising candidates for thermoelectric applications. This is primarily due to the increasing awareness of the deleterious effect of global warming on the planets environment, a renewed requirement for longlife electrical power sources, and the increasing miniaturization of electronic circuits and sensors. Recently, thermoelectric materials have attracted extensive attention again. Nanowires display enhanced thermoelectric potential by helen knight 12th june 2018 2. Nanowires display enhanced thermoelectric potential the. L, where t is the temperature, s is the seebeck coefficient. The efficiency of bulk thermoelectric materials suffers from their inability to transport charge carriers selectively based on energy. Silicon nanowires as efficient thermoelectric materials dtic. Thermoelectric properties of a single crystalline ag2te nanowire. Thermoelectric materials, capable of converting a thermal gradient to an electric field and vice versa, could be useful in power generation and. In contrast to threedimensional material, isolated nanowires conduct less heat and more electricity at the same time, said vasylenko, first author of a paper on this work in.
This can be done by structuring silicon into 1d structures or nanowires nws. We find the optimal thickness of the ge shell to provide the largest figure of merit for the devices. Advances in the optimization of siliconbased thermoelectrics. Among the nanoscale semiconductor materials, silicon germaniumsige alloy nanowire is a promising candidate for thermoelectric materials the thermal conductivities of sige coreshell nanowires.
J r 2008 silicon nanowires as efficient thermoelectric materials nature 451. Recently, however, using lowdimensional structures, it was demonstrated that zt could be greatly increased compared to their bulk counterparts, setting the stage for highly efficient te energy conversion. The atomic ratio of ag and te elements is approximately 2. It can also be defined as the ratio of the length to width being greater than. Silicon nanowires as efficient thermoelectric materials nature. Cvt synthesis of silicide nanowires using ni2si nanowires as an example. Silicon nanowires as efficient thermoelectric materials article pdf available in nature 4517175. Some of the important criteria for material selection are the cost, whether it is environmentally friendly, and abundance. Recent studies in nanostructured thermoelectric materials have led to a sudden increase in zt300k 1 1. Materials, synthesis, characterization and applications covers advanced materials for nanowires, the growth and synthesis of semiconductor nanowiresincluding methods such as solution growth, movpe, mbe, and selforganization. Resistance along the silicon nanowire array was measured to be ca.
Complete thermoelectric benchmarking of individual insb. Figure 3c shows the silicon nw array bridging the suspended mass and the bulk. Jun 12, 2018 evolution of thermoelectric figure of merit from 3d bulk to 1d snte behind and a collection of synthesised nanowires below. A relatively simple, scalable, and single component system of silicon nanowires with figure of merit of 1 at room temperature is. Among them, in ag 2 te, it was reported that the phase transition from monoclinic to cubic phase occurs at relatively low temperatures, so that extensive research for effective application using this material has been aroused. Thermoelectric properties of silicon and recycled silicon sawing waste. The quest for efficiency in thermoelectric nanowires. Nanotechnology 19 2008 435607 e sutter et al figure 1.
Pdf thermoelectric materials interconvert thermal gradients and electric fields for power generation or for refrigeration1,2. The efficiency of thermoelectric heat engines is bounded by the same maximum efficiency as cyclic heat engines, namely, by carnot efficiency. Silicon nanowires unexpectedly efficient te materials february 2008. Figure 1b reveals the temeds spectrum taken from a single ag 2 te nanowire. Some of the best thermoelectric materials are compounds of bi, te, pb, sb, ag, and exhibit zt 1 1, 2. Pdf silicon nanowires as efficient thermoelectric materials. Therefore, there is a huge amount of research e ort to get high thermoelectric e cient materials with a fair production value. Bi2te3 nanowire arrayepoxy composites for thermoelectric power generators. In the second part, the discovery of highly efficient thermoelectric materials based on silicon nanowires is discussed. Thermal conductivity of silicon nanowires embedded on. Efficiency is big in the tiny world of thermoelectric nanowires. Vaporliquidsolid growth of these nanowires is straightforward, but the traditional aucatalyzed method is expected to lead to au contamination and subsequently crystal defects. Lack of materials which are thermoelectrically efficient and economically attractive.
Thermoelectric properties of semiconductor nanowires. Experimental determination of the thermoelectric properties of porous silicon nanowires. Nanoscale semiconduction silicides as efficient thermoelectric materials. Materials like silicon nanowires, cadmium selenide nanorods, titania and zinc oxide nanowires are currently under focus for the photovoltaic applications 1. Silicon nanowire arrays as thermoelectric material for a power microgenerator. Thermoelectric properties of superlattice nanowires. This volume focuses on various aspects of nanowires for energy applications, presenting interesting sections on electrospun semiconductor metal oxide nanowires for energy and sensing applications, integration into flexible and functional materials.
The thermoelectric nanowire characterization platform tncp was produced by silicon micromachining. O guz gu lseren august, 20 nowadays, the use of thermoelectric semiconductor devices are limited by their low e ciencies. Isolated nanowires improve heattoelectricity conversion. Silicon nanowires as efficient thermoelectric materials. Electronic supplementary information esi for efficient fibershaped perovskite photovoltaics using silver nanowires as top electrode minoh lee,a yohan ko, b and yongseok junb a department of chemical engineering, ulsan national institute of science and technology unist, ulsan 689798, republic of korea. Jun 08, 2018 thermoelectric materials harvest waste heat and convert it into electricity and are much soughtafter as renewable and environmentally friendly sources of energy. Nanowires for energy applications, volume 98 1st edition. With the advances of nanostructure technology, many experiments nowadays can realize zt larger than one at room temperature in lowdimensional structures 3, 4.
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