Near-field thermal rectification devices using phase change periodic nanostructure

Abstract

We theoretically analyze two near-field thermal rectification devices: a radiative thermal diode and a thermal transistor that utilize a phase change material to achieve dynamic control over heat flow by exploiting metal-insulator transition of VO near 341 K. The thermal analogue of electronic diode allows high heat flow in one direction while it restricts the heat flow when the polarity of temperature gradient is reversed. We show that with the introduction of 1-D rectangular grating, thermal rectification is dramatically enhanced in the near-field due to reduced tunneling of surface waves across the interfaces for negative polarity. The radiative thermal transistor also works around phase transition temperature of VO and controls heat flow. We demonstrate a transistor-like behavior wherein heat flow across the source and the drain can be greatly varied by making a small change in gate temperature.

Solid‐State Thermal Control Devices

“…Ghanekar et al. [ 24 ] simulated the heat transport in a VO 2 –boron nitride (BN) diode based on near‐field radiation heat transport. In this model, VO 2 was working as the PCM and BN as the PIM.…”

“…The authors compared the calculation to a nongrating VO 2 structure, showing a much lower RR < 100% than with the grating diode. [ 24 ] The near‐field radiative heat transfer between the two blocks was theoretically obtained by using a Green's function formalism in both cases. [ 24 ] The authors claimed that in the grating structure, the phonon tunneling was strongly reduced in the reverse direction leading to an extremely low heat flux, while the heat flux in the forward direction almost stayed unchanged.…”

“…[ 24 ] The near‐field radiative heat transfer between the two blocks was theoretically obtained by using a Green's function formalism in both cases. [ 24 ] The authors claimed that in the grating structure, the phonon tunneling was strongly reduced in the reverse direction leading to an extremely low heat flux, while the heat flux in the forward direction almost stayed unchanged. [ 24 ] Hence, an extremely high thermal rectification was obtained in this particular design.…”

“…They represent new opportunities in the field, showing new material approaches [ 22,23 ] or suggestions for improving existing devices. [ 24 ] In Section 6, we discuss the future progress of thermal control devices.…”

Near-infrared optics of nanoparticles embedded silica thin films

“…The artificial thermal metamaterials which have selective high emissivity at narrowband or broadband wavelength range show promising potentials in the advanced engineering applications, such as thermophotovoltaics (TPVs), infrared thermal sensing [1][2][3][4][5][6][7][8], thermal diodes [9][10][11][12], radiation cooling [13][14][15][16], thermal rectification [17][18][19]43], biosensors, and chemical sensors [20,21]. Some materials, such as rare earth doped ceramics, possess selective high emissivity, but they do not show sufficient wavelength selectivity that are suitable for the emerging engineering applications [22].…”