Abstract
The performance of thermoelectric energy harvesters can be improved by nanostructures that exploit inelastic transport processes. One prototype is the three-terminal hopping thermoelectric device where electron hopping between quantum-dots are driven by hot phonons. Such three-terminal hopping thermoelectric devices have potential in achieving high efficiency or power via inelastic transport and without relying on heavy-elements or toxic compounds. We show in this work how output power of the device can be optimized via tuning the number and energy configuration of the quantum-dots embedded in parallel nanowires. We find that the staircase energy configuration with constant energy-step can improve the power factor over a serial connection of a single pair of quantum-dots. Moreover, for a fixed energy-step, there is an optimal length for the nanowire. Similarly for a fixed number of quantum-dots there is an optimal energy-step for the output power. Our results are important for future developments of high-performance nanostructured thermoelectric devices.
Highlights
Thermoelectric energy harvesting has the reverse effect as opposed to the thermoelectric refrigerator[1,2], and has been studied extensively in recent decades[3,4,5,6]
In this work we focus on phonon-assisted hopping thermoelectric transport in a three-terminal thermoelectric energy harvester
We show that the power factor is largest for staircase energy configuration
Summary
Configuration in Nanowires for Optimized Thermoelectric Power received: 21 October 2015 accepted: 01 August 2016 Published: 23 August 2016. Other prototypes of three-terminal inelastic thermoelectric devices include Coulomb coupled quantum-dots (QDs)[9,10], phonon-assisted hopping in QD chains (or localized states in 1D or 2D systems)[11,12,13,14,15], and inelastic thermoelectric transport across an electronic cavity promoted by mismatched resonant tunneling at the two-sides of the cavity[16,17,18,19]. Both the inelastic and elastic conductivity decreases with increasing dE.
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