Exploring packaging strategies of nano-embedded thermoelectric generators

Singha, Aniket; Mahanti, S. D.; Muralidharan, Bhaskaran

doi:10.1063/1.4933125

Cited by 14 publications

(21 citation statements)

References 41 publications

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“…Analyzing a voltage controlled SL-TE generator set up theoretically [7,[9][10][11][12], we investigate the performance in terms of output power and efficiency from an electrical engineering perspective [28,29] for various SL configurations. Using the non-equilibrium Green's function (NEGF) formalism coupled self-consistently with the Poisson's equation, we identify such an ideal structure and also demonstrate that it is almost immune to the deleterious effect of self-consistent charging and device variability.…”

Section: Introductionmentioning

confidence: 99%

Superlattice design for optimal thermoelectric generator performance

Priyadarshi¹,

Sharma²,

Mukherjee³

et al. 2018

J. Phys. D: Appl. Phys.

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We consider the design of an optimal superlattice thermoelectric generator via the energy bandpass filter approach. Various configurations of superlattice structures are explored to obtain a bandpass transmission spectrum that approaches the ideal "boxcar" form, which is now well known to manifest the largest efficiency at a given output power. Using the non-equilibrium Green's function formalism coupled self-consistently with the Poisson's equation, we identify such an ideal structure and also demonstrate that it is almost immune to the deleterious effect of self-consistent charging and device variability. Analyzing various superlattice designs, we conclude that superlattices with a Gaussian distribution of the barrier thickness offers the best thermoelectric efficiency at maximum power. It is observed that the best operating regime of this device design provides a maximum power in the range of 0.32-0.46 M W/m 2 at efficiencies between 54%-43% of Carnot efficiency. We also analyze our device designs with the conventional figure of merit approach to counter support the results so obtained. We note a high zT el = 6 value in the case of Gaussian distribution of the barrier thickness. With the existing advanced thin-film growth technology, the suggested superlattice structures can be achieved, and such optimized thermoelectric performances can be realized.

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Section: Introductionmentioning

confidence: 99%

Superlattice design for optimal thermoelectric generator performance

Priyadarshi¹,

Sharma²,

Mukherjee³

et al. 2018

J. Phys. D: Appl. Phys.

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“…where I C is the charge current, I Qe is the electronic heat current at the hot contact and V is the applied voltage assuming a voltage controlled set up described in recent literature [30][31][32][33][34][35][36] . Since thermal conductivity due to phonon doesn't vary significantly with the method employed to improve the thermoelectric performance (that is, Approach A or Approach B), we have simplified our calculations in (2) by neglecting the degradation in efficiency due to phonon heat conductivity.…”

Section: Introductionmentioning

confidence: 99%

“…where P A (η) and P B (η) are the maximum power densities obtained at efficiency η via Approach A and Approach B respectively, while P A (η) and P B (η) are taken along the operating line of our device 35 . It should be noted that although we use some specific parameters for simulation, the qualitative discussion as well as the trends noted in the simulated results are general and are valid irrespective of material specific parameters for a particular scattering mechanism.…”

Section: Introductionmentioning

confidence: 99%

Incoherent scattering can favorably influence energy filtering in nanostructured thermoelectrics

Singha

Muralidharan

2017

Sci Rep

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Investigating in detail the physics of energy filtering through a single planar energy barrier in nanostructured thermoelectric generators, we reinforce the non-trivial result that the anticipated enhancement in generated power at a given efficiency via energy filtering is a characteristic of systems dominated by incoherent scattering and is absent in ballistic devices. In such cases, assuming an energy dependent relaxation time τ(E) = kE r, we show that there exists a minimum value r min beyond which generation can be enhanced by embedding nanobarriers. For bulk generators with embedded nanobarriers, we delve into the details of inter sub-band scattering and show that it has finite contribution to the enhancement in generation. We subsequently discuss the realistic aspects, such as the effect of smooth transmission cut-off and show that for r > r min, the optimized energy barrier is just sufficiently wide enough to scatter off low energy electrons, a very wide barrier being detrimental to the performance. Analysis of the obtained results should provide general design guidelines for enhancement in thermoelectric generation via energy filtering. Our non-equilibrium approach is typically valid in the absence of local quasi-equilibrium and hence sets the stage for future advancements in thermoelectric device analysis, for example, Peltier cooling near a barrier interface.

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“…With the progress in fabrication and scaling technology, efficient heat harvesting in lower dimensional systems has gained a lot of attention [6][7][8][9][10][11][12][13][14][15][16]. One of the major issues affecting heat harvesting performance in nano-systems is the drastic lattice heat flux resulting from a small spatial separation between the heat reservoir and the heat sink.…”

Section: Introductionmentioning

confidence: 99%

A realistic non-local heat engine based on Coulomb coupled systems

Singha

2020

Preprint

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Optimal non-local heat-engines, based on Coulomb-coupled systems, demand a sharp step-like change in energy resolved system-to-reservoir coupling around the ground state of quantum-dots [1][2][3][4][5]. Such sharp step-like transition in the system-to-reservoir coupling cannot be achieved in a realistic scenario. Here, I propose realistic design for non-local heat engine based on Coulombcoupled systems. The performance of the proposed heat engine is then theoretically investigated using quantum-master-equation (QME) approach. It is demonstrated that the theoretical maximum power output for the proposed set-up is limited to about 50% of the optimal design. Despite a lower performance compared to the optimal set-up, the novelty of the proposed design is the conjunction of fabrication simplicity along with reasonable power output. At the end, the sequential transport processes leading to a performance deterioration of the proposed design strategy are analyzed and a method to alleviate such transport processes is proposed. The design proposed in this paper can be used to fabricate high-performance non-local cryogenic heat engines. FIG. 1. Schematic diagram of the proposed non-local heatengine based on Coulomb-coupled quantum dots. The entire system consists of three dots S1, S2 and G1 which are electrically coupled to the reservoirs L, R and G respectively. The dots S1 and S2 are tunnel coupled, while S1 and G1 are electrostatically coupled. The ground states of S1 and S2 form a staircase configuration with ε 2s ≈ ε 1 s +∆ε. In the proposed arrangement, current can be driven between the cold reservoirs L and R by absorbing thermal energy from the hot reservoir G.

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Exploring packaging strategies of nano-embedded thermoelectric generators

Cited by 14 publications

References 41 publications

Superlattice design for optimal thermoelectric generator performance

Superlattice design for optimal thermoelectric generator performance

Incoherent scattering can favorably influence energy filtering in nanostructured thermoelectrics

A realistic non-local heat engine based on Coulomb coupled systems

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