Recent NMR Studies of Thermoelectric Materials

Sirusi, Ali A.; Ross, Joseph H.

doi:10.1016/bs.arnmr.2017.04.002

Cited by 13 publications

(9 citation statements)

References 224 publications

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“…A change in temperature affects the self-polarization over the pyroelectric material, leading to electrical currents to compensate for those changes [19][20][21] . However, pyroelectric signals are transient and quickly decay to zero after a change in temperature has taken place, which is not suitable for long-term temperature monitoring [22][23][24][25] . By contrast, recently developed ionic thermoelectric sensors 26 can provide self-generated open-circuit voltages that are stable over time.…”

Section: Introductionmentioning

confidence: 99%

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Ultrasensitive electrolyte-assisted temperature sensor

et al. 2020

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Heat sensors form an important class of devices that are used across multiple fields and sectors. For applications such as electronic skin and health monitoring, it is particularly advantageous if the output electronic signals are not only high, stable, and reproducible, but also self-generated to minimize power consumption. Here, we present an ultrasensitive heat sensing concept that fulfills these criteria while also being compatible with scalable low-cost manufacturing on flexible substrates. The concept resembles a traditional thermocouple, but with separated electrodes bridged by a gel-like electrolyte and with orders of magnitudes higher signals (around 11 mV K−1). The sensor pixels provide stable and reproducible signals upon heating, which, for example, could be used for heat mapping. Further modification to plasmonic nanohole metasurface electrodes made the sensors capable of also detecting light-induced heating. Finally, we present devices on flexible substrates and show that they can be used to detect human touch.

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Section: Introductionmentioning

confidence: 99%

“…npj Flexible Electronics (2020)23 Published in partnership with Nanjing Tech University1234567890():,;…”

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confidence: 99%

Ultrasensitive electrolyte-assisted temperature sensor

et al. 2020

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“…Note that in the highly degenerate limit (µ − E C ≫ kT ), these results can easily be shown to simplify to K = const. and 1/T 1 ∝ T , as often seen for heavily doped semiconductors [44]. Here, we consider the more general case, since µ− E C ≈ kT for much of the range considered here.…”

Section: Theoretical Modeling and Analysismentioning

confidence: 94%

Charge-carrier behavior in Ba-, Sr- and Yb-filled CoSb3 : NMR and transport studies

et al. 2019

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We report 59 Co NMR and transport measurements on n-type filled skutterudites BaxYbyCo4Sb12 and AxCo4Sb12 (A= Ba, Sr), promising thermoelectric materials. The results demonstrate consistently that a shallow defect level near the conduction band minimum dominates the electronic behavior, in contrast to the behavior of unfilled CoSb3. To analyze the results, we modeled the defect as having a single peak in the density of states, occupied at low temperatures due to donated charges from filler atoms. We fitted the NMR shifts and spin-lattice relaxation rates allowing for arbitrary carrier densities and degeneracies. The results provide a consistent picture for the Hall data, explaining the temperature dependence of the carrier concentration. Furthermore, without adjusting model parameters, we calculated Seebeck coefficient curves, which also provide good consistency. In agreement with recently reported computational results, it appears that composite native defects induced by the presence of filler atoms can explain this behavior. These results provide a better understanding of the balance of charge carriers, of crucial importance for designing improved thermoelectric materials. SbCo guest atom or unfilled site FIG. 1. Crystal structure of filled skutterudites, M zT4X12 , where M is a guest atom (0 z 1).information about the electronic behavior and the importance of defects, very close in energy to the conduction band edge in these n-type filled skutterudites. II. SAMPLE PREPARATION AND EXPERIMENTAL METHODSSkutterudites (space group Im3, shown in Fig. 1, visualized with VESTA [19]) of nominal composition Ba 0.1 Yb 0.2 Co 4 Sb 12 , Ba 0.2 Co 4 Sb 12 , and Sr 0.2 Co 4 Sb 12were prepared by a melting-annealing-spark plasma sintering method. The high-purity elements were weighed and mixed in the stoichiometric ratio, loaded into graphite-coated quartz tubes, and sealed in vacuum. These were placed in a furnace and heated to 1373 K at

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“…NMR came to provide a simultaneous solution for measuring fluid saturation of multiple phases and determining a lithologyindependent porosity [44][45][46], pore throat size and network, permeability, and capillary pressure [8,13]. However, the NMR signal amplitude suffers reduction with the increase of temperature [47]. This attenuation in signal amplitudes is due to the Transverse Overhauser Effect [48], caused by heat attribution that increases the degree of freedom for ionic motion.…”

Section: Introductionmentioning

confidence: 99%

Quantum Dipolar Coupling Thermal Correction for NMR Signal during Natural Rock Flooding by Melding Experimentation and Numerical Simulation (Th-CENS)

Alfarisi¹,

Zhang²,

Ouzzane³

et al. 2022

Preprint

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Researchers have used NMR to measure multi-phase fluid saturation and distribution inside porous media of natural rock. However, the NMR signal amplitude suffers reduction with the increase of temperature. The main reason is the Transverse Overhauser Effect, where heating increases the freedom for ionic motion, affecting spinning behavior by having two spins go in two opposite directions to form the Dipolar Coupling. We approach solving NMR thermal effects correction by melding experimentation and numerical simulation method. We use NMR for Cretaceous carbonate rock multi-phase flow research. We conduct time step in-situ temperature measurement for four different sections of the flooding system at the inlet, center, and outlet along the flooding path. In addition, we conduct a temperature measurement at the NMR device radial axis, representing the permanent magnet temperature. We build a 3D cylindrical heat transfer model for the numerical simulator that simulates thermal effect distribution on the NMR for optimally generating the correction model. The insight provided by the simulator improved the understanding of the thermal distribution at the natural rock core plug to produce a better thermal correction model that meld experimentation and simulation, a method we call Th-CENS.

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Recent NMR Studies of Thermoelectric Materials

Cited by 13 publications

References 224 publications

Ultrasensitive electrolyte-assisted temperature sensor

Ultrasensitive electrolyte-assisted temperature sensor

Charge-carrier behavior in Ba-, Sr- and Yb-filled CoSb3 : NMR and transport studies

Quantum Dipolar Coupling Thermal Correction for NMR Signal during Natural Rock Flooding by Melding Experimentation and Numerical Simulation (Th-CENS)

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