- Quantum Interference Enhanced Thermoelectricity in Ferrocene Based Molecular Junctions. [Journal Article]
- JNJ Nanosci Nanotechnol 2019 Nov 01; 19(11):7452-7455
- Recent experimental indications of room-temperature quantum interference in the sub-nanometer single molecules suggest that such effects could be utilized to engineer thermoelectric properties of org…
Recent experimental indications of room-temperature quantum interference in the sub-nanometer single molecules suggest that such effects could be utilized to engineer thermoelectric properties of organic single molecule junctions. In this paper, we show that the thermoelectric power factor is significantly enhanced in double path ferrocene cycles compared to the single path counterpart. Due to quantum interference in the double path structure, the Seebeck coefficient is significantly enhanced while the conductance is less affected compared to single path structure. The power factor of the ferrocene cycles are 1-2 orders of magnitude higher than the best organic material reported today. This opens new avenues for future molecular scale organometallic thermoelectricity.
- Measuring Device and Material ZT in a Thin-Film Si-Based Thermoelectric Microgenerator. [Journal Article]
- NNanomaterials (Basel) 2019 Apr 24; 9(4)
- Thermoelectricity (TE) is proving to be a promising way to harvest energy for small applications and to produce a new range of thermal sensors. Recently, several thermoelectric generators (TEGs) base…
Thermoelectricity (TE) is proving to be a promising way to harvest energy for small applications and to produce a new range of thermal sensors. Recently, several thermoelectric generators (TEGs) based on nanomaterials have been developed, outperforming the efficiencies of many previous bulk generators. Here, we presented the thermoelectric characterization at different temperatures (from 50 to 350 K) of the Si thin-film based on Phosphorous (n) and Boron (p) doped thermocouples that conform to a planar micro TEG. The thermocouples were defined through selective doping by ion implantation, using boron and phosphorous, on a 100 nm thin Si film. The thermal conductivity, the Seebeck coefficient, and the electrical resistivity of each Si thermocouple was experimentally determined using the in-built heater/sensor probes and the resulting values were refined with the aid of finite element modeling (FEM). The results showed a thermoelectric figure of merit for the Si thin films of z T = 0.0093, at room temperature, which was about 12% higher than the bulk Si. In addition, we tested the thermoelectric performance of the TEG by measuring its own figure of merit, yielding a result of ZT = 0.0046 at room temperature.
- On Behind the Physics of the Thermoelectricity of Topological Insulators. [Journal Article]
- SRSci Rep 2019 Apr 19; 9(1):6324
- Topological Insulators are the best thermoelectric materials involving a sophisticated physics beyond their solid state and electronic structure. We show that exists a topological contribution to the…
Topological Insulators are the best thermoelectric materials involving a sophisticated physics beyond their solid state and electronic structure. We show that exists a topological contribution to the thermoelectric effect that arises between topological and thermal quantum field theories applied at very low energies. This formalism provides us with a quantized topological mass proportional to the temperature T leading, through an electric potential V, to a Seebeck coefficient where we identify an anomalous contribution that can be associated to the creation of real electron-hole Schwinger's pairs close to the topological bands. Finally, we find a general expression for the dimensionless figure of merit of these topological materials, considering only the electronic contribution, getting a value of 2.73 that is applicable to the Bi2Te3, for which it was reported a value of 2.4 after reducing its phononic contribution, using only the most basic topological numbers (0 or 1).
- Farming thermoelectric paper. [Journal Article]
- EEEnergy Environ Sci 2019 Feb 01; 12(2):716-726
- Waste heat to electricity conversion using thermoelectric generators is emerging as a key technology in the forthcoming energy scenario. Carbon-based composites could unleash the as yet untapped pote…
Waste heat to electricity conversion using thermoelectric generators is emerging as a key technology in the forthcoming energy scenario. Carbon-based composites could unleash the as yet untapped potential of thermoelectricity by combining the low cost, easy processability, and low thermal conductivity of biopolymers with the mechanical strength and good electrical properties of carbon nanotubes (CNTs). Here we use bacteria in environmentally friendly aqueous media to grow large area bacterial nanocellulose (BC) films with an embedded highly dispersed CNT network. The thick films (≈10 μm) exhibit tuneable transparency and colour, as well as low thermal and high electrical conductivity. Moreover, they are fully bendable, can conformally wrap around heat sources and are stable above 500 K, which expands the range of potential uses compared to typical conducting polymers and composites. The high porosity of the material facilitates effective n-type doping, enabling the fabrication of a thermoelectric module from farmed thermoelectric paper. Because of vertical phase separation of the CNTs in the BC composite, the grown films at the same time serve as both the active layer and separating layer, insulating each thermoelectric leg from the adjacent ones. Last but not least, the BC can be enzymatically decomposed, completely reclaiming the embedded CNTs.
- Two-dimensional tellurium-polymer membrane for ultrafast photonics. [Journal Article]
- NNanoscale 2019 Mar 28; 11(13):6235-6242
- Tellurium (Te) exhibits many intriguing properties including thermoelectricity, photoelectricity, piezoelectricity, and photoconductivity, and is widely used in detectors, sensors, transistors, and e…
Tellurium (Te) exhibits many intriguing properties including thermoelectricity, photoelectricity, piezoelectricity, and photoconductivity, and is widely used in detectors, sensors, transistors, and energy devices. Herein, ultrathin two-dimensional (2D) Te nanosheets were fabricated using a facile and cost-effective liquid-phase exfoliation method. Mixing the as-prepared 2D Te nanosheets with polyvinylpyrrolidone (PVP) provided a uniform 2D Te/PVP membrane. The 2D Te/PVP membrane exhibited excellent mechanical properties, thermal properties, and stability. The nonlinear optical properties of the membrane were characterized over the spectral range of 800 to 1550 nm using open-aperture Z-scan technology. A large nonlinear absorption coefficient of about 10-1 cm GW-1 over the whole tested wavelength range demonstrated the efficient broadband saturable absorptivity of the 2D Te/PVP membrane. Using the 2D Te/PVP membrane as a saturable absorber (SA), a highly stable femtosecond laser with a pulse duration of 829 fs in the communication band was obtained. This work highlights the promise of 2D Te/PVP membranes in ultrafast photonics and Te as a new 2D material for use in photonic devices such as all-optical modulators, switches, and thresholds.
- Making flexible spin caloritronic devices with interconnected nanowire networks. [Journal Article]
- SASci Adv 2019; 5(3):eaav2782
- Spin caloritronics has recently emerged from the combination of spintronics and thermoelectricity. Here, we show that flexible, macroscopic spin caloritronic devices based on large-area interconnecte…
Spin caloritronics has recently emerged from the combination of spintronics and thermoelectricity. Here, we show that flexible, macroscopic spin caloritronic devices based on large-area interconnected magnetic nanowire networks can be used to enable controlled Peltier cooling of macroscopic electronic components with an external magnetic field. We experimentally demonstrate that three-dimensional CoNi/Cu multilayered nanowire networks exhibit an extremely high, magnetically modulated thermoelectric power factor up to 7.5 mW/K2m and large spin-dependent Seebeck and Peltier coefficients of -11.5 μV/K and -3.45 mV at room temperature, respectively. Our investigation reveals the possibility of performing efficient magnetic control of heat flux for thermal management of electronic devices and constitutes a simple and cost-effective pathway for fabrication of large-scale flexible and shapeable thermoelectric coolers exploiting the spin degree of freedom.
- Thermoelectric transport properties in magnetically ordered crystals. Corrigendum and addenda. [Journal Article]
- ACActa Crystallogr A Found Adv 2019 03 01; 75(Pt 2):409
- A correction and additions concerning the limiting point groups are made to the article by Grimmer [Acta Cryst. (2017), A73, 333-345].
A correction and additions concerning the limiting point groups are made to the article by Grimmer [Acta Cryst. (2017), A73, 333-345].
- CuPt Alloy Thin Films for Application in Spin Thermoelectrics. [Journal Article]
- SRSci Rep 2019 Feb 28; 9(1):3133
- Spin thermoelectrics represents a new paradigm of thermoelectricity that has a potential to overcome the fundamental limitation posed by the Wiedmann-Franz law on the efficiency of conventional therm…
Spin thermoelectrics represents a new paradigm of thermoelectricity that has a potential to overcome the fundamental limitation posed by the Wiedmann-Franz law on the efficiency of conventional thermoelectric devices. A typical spin thermoelectric device consists of a bilayer of a magnetic insulator and a high spin-orbit coupling (SOC) metal coated over a non-magnetic substrate. Pt is the most commonly used metal in spin thermoelectric devices due to its strong SOC. In this paper, we found that an alloy of Cu and Pt can perform much better than Pt in spin thermoelectric devices. A series of CuPt alloy films with different Pt concentrations were deposited on yttrium iron garnet (YIG) films coated gadolinium gallium garnet (GGG) substrate. Through spin Seebeck measurements, it was found that the Cu0.4Pt0.6/YIG/GGG device shows almost 3 times higher spin Seebeck voltage compared to Pt/YIG/GGG under identical conditions. The improved performance was attributed to the higher resistivity as well as enhanced spin hall angle of the CuPt layer.
- In-Plane Isotropic/Anisotropic 2D van der Waals Heterostructures for Future Devices. [Review]
- SSmall 2019; 15(11):e1804733
- Mono- to few-layers of 2D semiconducting materials have uniquely inherent optical, electronic, and magnetic properties that make them ideal for probing fundamental scientific phenomena up to the 2D q…
Mono- to few-layers of 2D semiconducting materials have uniquely inherent optical, electronic, and magnetic properties that make them ideal for probing fundamental scientific phenomena up to the 2D quantum limit and exploring their emerging technological applications. This Review focuses on the fundamental optoelectronic studies and potential applications of in-plane isotropic/anisotropic 2D semiconducting heterostructures. Strong light-matter interaction, reduced dimensionality, and dielectric screening in mono- to few-layers of 2D semiconducting materials result in strong many-body interactions, leading to the formation of robust quasiparticles such as excitons, trions, and biexcitons. An in-plane isotropic nature leads to the quasi-2D particles, whereas, an anisotropic nature leads to quasi-1D particles. Hence, in-plane isotropic/anisotropic 2D heterostructures lead to the formation of quasi-1D/2D particle systems allowing for the manipulation of high binding energy quasi-1D particle populations for use in a wide variety of applications. This Review emphasizes an exciting 1D-2D particles dynamic in such heterostructures and their potential for high-performance photoemitters and exciton-polariton lasers. Moreover, their scopes are also broadened in thermoelectricity, piezoelectricity, photostriction, energy storage, hydrogen evolution reactions, and chemical sensor fields. The unique in-plane isotropic/anisotropic 2D heterostructures may open the possibility of engineering smart devices in the nanodomain with complex opto-electromechanical functions.
New Search Next
- Possible Routes for Efficient Thermo-Electric Energy Conversion in a Molecular Junction. [Journal Article]
- CChemphyschem 2019 03 18; 20(6):848-860
- In the context of designing an efficient thermoelectric energy-conversion device at nanoscale level, we suggest several important tuning parameters to enhance the performance of thermoelectric conver…
In the context of designing an efficient thermoelectric energy-conversion device at nanoscale level, we suggest several important tuning parameters to enhance the performance of thermoelectric converters. We consider a simple molecular junction, which is always helpful to understand the basic mechanisms in a deeper way, where a benzene molecule is coupled to two external baths having unequal temperatures. The key component responsible for achieving better performance is associated with the asymmetric nature of transmission function, and in the present work, we show that it can be implemented in different ways by regulating the physical parameters involving the system. Employing a tight-binding framework we calculate electrical and thermal conductances, thermopower, and figure of merit (FOM) by using Landauer integrals, and thoroughly examine the critical roles played by molecule-to-lead (ML) interface geometry, magnetic field, chemical substituent group, ML coupling, and the direct coupling between the two leads. Our results show that a reasonably large FOM (≫1) can be obtained and lead to a possibility of regulating the efficiency by selectively tuning the physical parameters. We believe that the present analysis will enhance the understanding of designing efficient thermoelectric devices, and can be verified in a laboratory.