Efficiency of Energy Conversion in Thermoelectric Nanojunctions

Abstract

Using first-principles approaches, this study investigated the efficiency of energy conversion in nanojunctions, described by the thermoelectric figure of merit $ZT$. We obtained the qualitative and quantitative descriptions for the dependence of $ZT$ on temperatures and lengths. A characteristic temperature: $T_0=\sqrt{\beta /\gamma (l)}$ was observed. When $T\ll T_0$, $ZT\propto T^2$. When $T\gg T_0$, $ZT$ tends to a saturation value. The dependence of $ZT$ on the wire length for the metallic atomic chains is opposite to that for the insulating molecules: for aluminum atomic (conducting) wires, the saturation value of $ZT$ increases as the length increases; while for alkanethiol (insulating) chains, the saturation value of $ZT$ decreases as the length increases. $ZT$ can also be enhanced by choosing low-elasticity bridging materials or creating poor thermal contacts in nanojunctions. The results of this study may be of interest to research attempting to increase the efficiency of energy conversion in nano thermoelectric devices.

2 figures

References in corpus (16)

• Thermoelectric effect in molecular electronics
• Giant thermopower and figure of merit in single-molecule devices
• Theory of local heating in nanoscale conductors
• Electron- and phonon transport in silicon nanowires: an atomistic approach to thermoelectric properties
• Theory of non-equilibrium thermoelectric effects in nanoscale junctions
• Length-dependent conductance and thermopower in single-molecule junctions of dithiolated oligophenylene derivatives
• Thermopower of atomic-size metallic contacts
• High-bias stability of monatomic chains
• Inelastic current-voltage characteristics of atomic and molecular junctions
• Inelastic effects in molecular junction transport: Scattering and self-consistent calculations for the Seebeck coefficient
• Role of heating and current-induced forces in the stability of atomic wires
• Conduction Mechanism in a Molecular Hydrogen Contact
• Seebeck coefficient of thermoelectric moleculat junction: First-principles calculations
• Effect of electron-phonon scattering on shot noise in nanoscale junctions
• Thermal Transport through a Mesoscopic Weak Link
• Alkanethiol-Based Single-Molecule Transistors

Cited by in corpus (17)

• Large enhancement of thermoelectric effects in a double quantum dot system due to interference and Coulomb correlation phenomena
• Giant Thermoelectric Effect from Transmission Supernodes
• Efficiency fluctuations in quantum thermoelectric devices
• Enhancement of thermoelectric efficiency and violation of the Wiedemann-Franz law due to Fano effect
• First-principles quantum transport modeling of thermoelectricity in single-molecule nanojunctions with graphene nanoribbon electrodes
• Molecular dynamics study of the thermopower of Ag, Au, and Pt nanocontacts
• Thermal transport and non-equilibrium temperature drop across a magnetic nanostructured interface
• Seebeck Coefficients in Nanoscale Junctions: Effects of Electron-vibration Scattering and Local Heating
• Molecular Heat Engines: Quantum Coherence Effects
• Effect of Thermoelectric Cooling in Nanoscale Junctions
• The effect of Coulomb interactions on thermoelectric properties of quantum dots
• Origin of thermoelectric response fluctuations in single-molecule junctions
• The effect of dephasing on thermoelectric efficiency of molecular junctions
• The effect of fluctuations - thermal and otherwise - on the temperature dependence of thermopower in aromatic chain single-molecule junctions
• Thermoelectric optimization and quantum-to-classical crossover in gate-controlled two-dimensional semiconducting nanojunctions
• Scattering theory of thermocurrent in quantum dots and molecules
• A Strongly Correlated Quantum-Dot Heat Engine with Optimal Performance: An Non-equilibrium Green's function Approach