Thermionic-enhanced near-field thermophotovoltaics

Datas Medina, Alejandro ORCID: and Vaillon, Rodolphe (2019). Thermionic-enhanced near-field thermophotovoltaics. "Nano Energy", v. 61 ; pp. 10-17. ISSN 2211-2855.


Title: Thermionic-enhanced near-field thermophotovoltaics
Item Type: Article
Título de Revista/Publicación: Nano Energy
Date: July 2019
ISSN: 2211-2855
Volume: 61
Freetext Keywords: Nanoscale energy conversion; Thermophotovoltaics; Thermionics; Near-field radiation
Faculty: E.T.S.I. Telecomunicación (UPM)
Department: Electrónica Física
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Solid-state heat-to-electrical power converters are thermodynamic engines that use fundamental particles, such as electrons or photons, as working fluids. Virtually all commercially available devices are thermoelectric generators, in which electrons flow through a solid driven by a temperature difference. Thermophotovoltaics and thermionics are highly efficient alternatives relying on the direct emission of photons and electrons. However, the low energy flux carried by the emitted particles significantly limits their generated electrical power density potential. Creating nanoscale vacuum gaps between the emitter and the receiver in thermionic and thermophotovoltaic devices enables a significant enhancement of the electron and photon energy fluxes, respectively, which in turn results in an increase of the generated electrical power density. Here we propose a thermionic-enhanced near-field thermophotovoltaic device that exploits the simultaneous emission of photons and electrons through nanoscale vacuum gaps. We present the theoretical analysis of a device in which photons and electrons travel from a hot LaB6-coated tungsten emitter to a closely spaced BaF2-coated InGaAs photovoltaic cell. Photon tunnelling and space charge removal across the nanoscale vacuum gap produce a drastic increase in flux of electrons and photons, and subsequently, of the generated electrical power density. We show that conversion efficiencies and electrical power densities of ∼ 30% and ∼ 70 W/cm2 are achievable at 2000 K for a practicable gap distance of 100 nm, and thus greatly enhance the performances of stand-alone near-field thermophotovoltaic devices (∼10% and ∼10 W/cm2). A key practical advantage of this nanoscale energy conversion device is the use of grid-less cell designs, eliminating the issue of series resistance and shadowing losses, which are unavoidable in conventional near-field thermophotovoltaic devices.

Funding Projects

Government of Spain
Células solares de bajo GAP para aplicaciones termofotovoltaicas de alta temperatura
Horizon 2020
Next GenerAtion MateriAls and Solid State DevicEs for Ultra High Temperature Energy Storage and Conversion
Government of Spain

More information

Item ID: 63892
DC Identifier:
OAI Identifier:
DOI: 10.1016/j.nanoen.2019.04.039
Official URL:
Deposited by: Memoria Investigacion
Deposited on: 05 Dec 2020 09:03
Last Modified: 01 Aug 2021 22:30
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